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In Italy, watermelon cultivation spans 9510 hectares, with production levels largely influenced by seasonal market demand. As a result, surplus watermelon left unsold by September often remain in the fields, where they decompose naturally and go to waste. A chemical analysis of the watermelon liquid fraction waste (WW) indicates a high carbohydrate concentration, highlighting the potential for biotechnological valorization of this waste stream, converting it into lipids or exopolysaccharides (EPSs). This study investigates the feasibility of utilizing WW as an alternative growth substrate for microalgae, aligning with circular economy principles and advancing sustainable agricultural practices. By repurposing agricultural byproducts, this research supports biorefinery objectives, aiming to convert biomass into high-value secondary products, including biofuels, pigments, and nutraceuticals. Scenedesmus and Chlorella strains demonstrated promising growth and adaptability in WW, achieving biomass yields of 0.95 ± 0.07 g L−1 and 0.37 ± 0.02 g L−1, respectively, with a significant EPS production observed as medium gelation. Although lipid accumulation was limited in this case by the WW substrate, the lipid profiles of both strains were distinctively altered, notably lacking linolenic acid. [ABSTRACT FROM AUTHOR]

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This study investigated the potential of Scenedesmus sp. (SCM) and Aurantiochytrium spp. (AUM) meals as protein and lipid sources in practical diets for juvenile Penaeus vannamei. In phase I, a reference diet (0-R) was formulated with 150.0 g kg−1 fish meal (FM). Four other diets replaced FM with SCM at 25, 50, 75, and 100%. Diets were evaluated with 2,000 shrimp of 1.99 ± 0.15 g body weight (BW) stocked in 40 indoor tanks of 0.5 m3 under 80 animals m−2 for 75 days. Subsequently, feed preference was assessed by simultaneously confronting all diets and measuring their relative apparent feed intake (RAFI). In phase II, a control diet was formulated with 120.0 g kg−1 FM and 12.0 g kg−1 fish oil. Four fish-free diets fully replaced these ingredients with 50.0, 200.0, 250.0, and 300.0 g kg−1 SCM and a fixed level of AUM at 15.0 g kg−1. A total of 3,570 shrimp of 1.78 ± 0.16 g were stocked in thirty-five 1-m3 outdoor tanks under 100 animals m−2 and fed for 71 days. In phase I, final shrimp survival (96.6 ± 3.4%), weekly growth (1.09 ± 0.05 g), gained yield (982 ± 47 g m−2), and FCR (1.56 ± 0.07) were unaffected by FM replacement (P > 0.05). RAFI significantly dropped at 75 and 100% FM replacements (P < 0.05). The highest RAFI was observed for the reference diet and the lowest when FM was completely removed (P < 0.05). In phase II, final survival (94.3 ± 3.8%), and weekly growth (0.85 ± 0.02 g) did not differ significantly. Shrimp fed 0-I diet achieved the highest BW (12.24 ± 0.93 g) and those fed diet 300-I the lowest (9.25 ± 1.00 g; P < 0.05). The highest gained yield (921 ± 70 and 828 ± 45 g m−2), and the lowest FCR (1.52 ± 0.10 and 1.61 ± 0.08) was found for shrimp raised with the reference and 200-I diets, respectively (P < 0.05). Our findings indicate that Scenedesmus sp. meal can be included in shrimp diets up to 150 g kg−1 and fully replace FM protein on a weight-to-weight basis. However, replacing all marine proteins and oils with Scenedesmus sp. and Aurantiochytrium spp. meals significantly reduced feed attractability and shrimp performance. Future research should focus on refining fish-free diet formulations containing SCM and AUM to ensure they meet all essential nutrient requirements and improve feed attractability. [ABSTRACT FROM AUTHOR]

Abstract Scenedesmus sp. is a species of the Scenedesmus genus within the phylum Chlorophyta, commonly found as a planktonic algal species in freshwater and known for its rapid growth rate. This study employs room-temperature, atmospheric-pressure plasma mutagenesis for the breeding of Scenedesmus sp., utilizing transcriptomic analysis to investigate the biosynthesis mechanism of triglycerides. Further analysis of differentially expressed genes in transcriptome by measuring the macroscopic biological indicators of mutant and original algal strains. The findings of the study suggest that the mutant strain's photosynthesis has been enhanced, leading to improved light energy utilization and CO2 fixation, thereby providing more carbon storage and energy for biomass and lipid production. The intensification of glycolysis and the TCA (tricarboxylic acid) cycle results in a greater shift in carbon flux towards lipid accumulation. An elevated expression level of related enzymes in starch and protein degradation pathways may enhance acetyl CoA accumulation, facilitating a larger substrate supply for fatty acid production and thereby increasing lipid yield.

Scenedesmus sp. is a species of the Scenedesmus genus within the phylum Chlorophyta, commonly found as a planktonic algal species in freshwater and known for its rapid growth rate. This study employs room-temperature, atmospheric-pressure plasma mutagenesis for the breeding of Scenedesmus sp., utilizing transcriptomic analysis to investigate the biosynthesis mechanism of triglycerides. Further analysis of differentially expressed genes in transcriptome by measuring the macroscopic biological indicators of mutant and original algal strains. The findings of the study suggest that the mutant strain's photosynthesis has been enhanced, leading to improved light energy utilization and CO2 fixation, thereby providing more carbon storage and energy for biomass and lipid production. The intensification of glycolysis and the TCA (tricarboxylic acid) cycle results in a greater shift in carbon flux towards lipid accumulation. An elevated expression level of related enzymes in starch and protein degradation pathways may enhance acetyl CoA accumulation, facilitating a larger substrate supply for fatty acid production and thereby increasing lipid yield. [ABSTRACT FROM AUTHOR]

Improper disposal of municipal solid waste led to the release of heavy metals into the environment through leachate accumulation, causing a range of health and environmental problems. Phycoremediation, using microalgae to remove heavy metals from contaminated water, was investigated as a promising alternative to traditional remediation methods. This study explored the potential of Scenedesmus sp. as a phycoremediation agent for heavy metal removal from landfill leachate. The study was conducted in batch, continuous, and membrane bioreactor (MBR). In the batch system, Scenedesmus sp. was added to the leachate and incubated for 15 days before the biomass was separated from the suspension. In the continuous system, Scenedesmus sp. was cultured in a flow-through system, and the leachate was continuously fed into the system with flow rates measured at 120, 150, and 180 mL/h for 27 days. The MBR system was similar to the continuous system, but it incorporated a membrane filtration step to remove suspended solids from the treated water. The peristaltic pump was calibrated to operate at five different flow rates: 0.24 L/h, 0.30 L/h, 0.36 L/h, 0.42 L/h, and 0.48 L/h for the MBR system and ran for 24 h. The results showed that Scenedesmus sp. was effective in removing heavy metals such as lead (Pb), cobalt (Co), chromium (Cr), nickel (Ni), and zinc (Zn) from landfill leachate in all three systems. The highest removal efficiency was observed for Ni, with a removal of 0.083 mg/L in the MBR and 0.068 mg/L in batch mode. The lowest removal efficiency was observed for Zn, with a removal of 0.032 mg/L in the MBR, 0.027 mg/L in continuous mode, and 0.022 mg/L in batch mode. The findings depicted that the adsorption capacity varied among the studied metal ions, with the highest capacity observed for Ni (II) and the lowest for Zn (II), reflecting differences in metal speciation, surface charge interactions, and affinity for the adsorbent material. These factors influenced the adsorption process and resulted in varying adsorption capacities for different metal ions. The study also evaluated the biomass growth of Scenedesmus sp. and found that it was significantly influenced by the initial metal concentration in the leachate. The results of this study suggest that Scenedesmus sp. can be used as an effective phycoremediation agent for removing heavy metals from landfill leachate. [ABSTRACT FROM AUTHOR]

Microalgae are vital for their photosynthetic abilities, contributing significantly to global oxygen production, serving as a key trophic level in aquatic ecosystems, aiding in biofuel production, assisting in wastewater treatment, and facilitating the synthesis of valuable biochemicals. Despite these advantages, photosynthetic microalgae are sensitive to salt stress, which alters their physiochemical and metabolic status, ultimately reducing microalgal growth. This sensitivity highlights the importance of understanding the impact of elevated salt content on the physiochemical, metabolic, and transcriptomic profiling of Scenedesmus sp., areas that are not yet fully understood. Our findings indicate that elevated salt stress decreases photosynthetic efficiency and increases non-regulated photochemical quenching of photosystem II (PSII). Moreover, PSII-driven linear electron flow (LEF) decreased, whereas photosystem I (PSI)-driven cyclic electron flow (CEF) increased in salt-stressed cells. To better understand the electron flow from PSII to PSI under elevated salt treatment, we analyzed the excitation energy flux per reaction center (RC), per cross-section (CS), energy flux ratios, and the potential index of PSII. Additionally, flow cytometry graphs depict the viability assay of Scenedesmus sp. BHU1. Our observations further revealed an increase in biochemical attributes, such as stress biomarkers, osmoprotectants, and enzymatic antioxidants, which help scavenge reactive oxygen species (ROS) under salt stress. Intracellular cations (Na + and Ca2+) were increased, while K+ levels decreased, indicating mechanisms of cellular homeostasis under salt stress. UHPLC-HRMS-based lipidome analysis confirmed that increasing salt stress induces the hyperaccumulation of several fatty acids involved in adaptation. Moreover, transcriptome analysis revealed the upregulation of genes associated with PSI, glycolysis, starch metabolism, sucrose metabolism, and lipid accumulation under salt stress. In contrast, genes related to PSII and C3 carbon fixation were downregulated to mitigate the adverse effects of salt stress.

Abstract Plastic consumption has increased globally, and environmental issues associated with it have only gotten more severe; as a result, the search for environmentally friendly alternatives has intensified. Polyhydroxyalkanoates (PHA), as biopolymers produced by microalgae, might be an excellent option; however, large-scale production is a relevant barrier that hinders their application. Recently, innovative materials such as carbon dots (CDs) have been explored to enhance PHA production sustainably. This study added green synthesized multi-doped CDs to Scenedesmus sp. microalgae cultures to improve PHA production. Prickly pear was selected as the carbon precursor for the hydrothermally synthesized CDs doped with nitrogen, phosphorous, and nitrogen–phosphorous elements. CDs were characterized by different techniques, such as FTIR, SEM, ζ potential, UV–Vis, and XRD. They exhibited a semi-crystalline structure with high concentrations of carboxylic groups on their surface and other elements, such as copper and phosphorus. A medium without nitrogen and phosphorous was used as a control to compare CDs-enriched mediums. Cultures regarding biomass growth, carbohydrates, lipids, proteins, and PHA content were analyzed. The obtained results demonstrated that CDs-enriched cultures produced higher content of biomass and PHA; CDs-enriched cultures presented an increase of 26.9% in PHA concentration and an increase of 32% in terms of cell growth compared to the standard cultures.

Plastic consumption has increased globally, and environmental issues associated with it have only gotten more severe; as a result, the search for environmentally friendly alternatives has intensified. Polyhydroxyalkanoates (PHA), as biopolymers produced by microalgae, might be an excellent option; however, large-scale production is a relevant barrier that hinders their application. Recently, innovative materials such as carbon dots (CDs) have been explored to enhance PHA production sustainably. This study added green synthesized multi-doped CDs to Scenedesmus sp. microalgae cultures to improve PHA production. Prickly pear was selected as the carbon precursor for the hydrothermally synthesized CDs doped with nitrogen, phosphorous, and nitrogen–phosphorous elements. CDs were characterized by different techniques, such as FTIR, SEM, ζ potential, UV–Vis, and XRD. They exhibited a semi-crystalline structure with high concentrations of carboxylic groups on their surface and other elements, such as copper and phosphorus. A medium without nitrogen and phosphorous was used as a control to compare CDs-enriched mediums. Cultures regarding biomass growth, carbohydrates, lipids, proteins, and PHA content were analyzed. The obtained results demonstrated that CDs-enriched cultures produced higher content of biomass and PHA; CDs-enriched cultures presented an increase of 26.9% in PHA concentration and an increase of 32% in terms of cell growth compared to the standard cultures. [ABSTRACT FROM AUTHOR]

The exploration of the biodiversity of cyanobacteria and microalgae holds great promise for obtaining pigments of industrial interest. This study focused on the bioprospecting of these organisms to obtain pigments of industrial interest together with enriched biomass. We investigated the impact of photoperiod and concentration of C/N/P nutrient sources in heterotrophic cultures, controlling specific variables such as light intensity, volume, pH, temperature, air flow and time to produce phycobiliproteins in Arthrospira platensis UTEX1926 and total carotenoids in Scenedesmus sp. using a nonfactorial Plackett‒Burman design in STATISTICA 7.0 software. The biomass concentration was determined by dry weight, while the concentrations of phycocyanin and carotenoids were determined spectrophotometrically at specific wavelengths. Heterotrophic cultures demonstrated superior productivity, with phycocyanin and carotenoids achieving percentages of 7% and 0.4% (w/w), respectively, and an R2 value of 0.99. Among the influential parameters, potassium diphosphate and sodium bicarbonate played pivotal roles in the final deposition of carotenoids and phycocyanin, respectively, yielding concentrations of 96.5 mg/L phycocyanin and 6.5 mg/L carotenoids. [ABSTRACT FROM AUTHOR]

In Italy, watermelon cultivation spans 9510 hectares, with production levels largely influenced by seasonal market demand. As a result, surplus watermelon left unsold by September often remain in the fields, where they decompose naturally and go to waste. A chemical analysis of the watermelon liquid fraction waste (WW) indicates a high carbohydrate concentration, highlighting the potential for biotechnological valorization of this waste stream, converting it into lipids or exopolysaccharides (EPSs). This study investigates the feasibility of utilizing WW as an alternative growth substrate for microalgae, aligning with circular economy principles and advancing sustainable agricultural practices. By repurposing agricultural byproducts, this research supports biorefinery objectives, aiming to convert biomass into high-value secondary products, including biofuels, pigments, and nutraceuticals. Scenedesmus and Chlorella strains demonstrated promising growth and adaptability in WW, achieving biomass yields of 0.95 ± 0.07 g L−1 and 0.37 ± 0.02 g L−1, respectively, with a significant EPS production observed as medium gelation. Although lipid accumulation was limited in this case by the WW substrate, the lipid profiles of both strains were distinctively altered, notably lacking linolenic acid.

Cold climate ecosystems hint the researchers to discover economically native cold-adapted strains, which can tolerate temperature fluctuations in outdoor large-scale cultivation for producing lipids as biofuel or for nutritional applications. Cheshmeh-Sabz Lake (Iran) was screened in winter. The lake water was sampled at 5 °C and three strains of Scenedesmus sp. (dominant in BG-11), Ankistrodesmus sp. (dominant in WC), and Chlorella sp. (dominant in BBM) were identified using molecular methods. Strains' growth parameters, lipid content, and lipid productivity were also investigated at 8 and 25 °C. Scenedesmus sp. had the most biomass productivity (~ 0.54 ± 0.001 g/L*d) with no significant difference at 8 and 25 °C and demonstrated the highest amount of lipid productivity at 25 °C (9.43 ± 1.05 g/L*d). Scenedesmus sp. produced the highest percentage of α-linolenic acid at 15 and 25 °C (10.96 ± 1.5% and 11.07 ± 0.31%, respectively) among the strains. There was no significant difference for palmitic acid content at 8, 15, and 25 °C (41.05 ± 5.2, 38.48 ± 4.25, and 39.82 ± 1.58% respectively). Biomass productivity decreased in Ankistrodesmus sp. and Chlorella sp. at 8 °C in comparison to that of 25 °C (~ 86% and ~ 34% decrease, respectively). Ankistrodesmus sp. produced the highest proportion of α-linolenic acid at 8 °C (9.98 ± 0.10%). The highest percentage of palmitic acid was observed in Chlorella at 25 °C (44.41 ± 7.56%). Based on the results, Scenedesmus sp. is the proper choice for outdoor cultivation at different seasons due to its relatively high biomass productivity and the specific growth rate in low and high temperatures (8 and 25 °C). [ABSTRACT FROM AUTHOR]

Recently, the use of microalgae in the treatment of olive mill wastewater as a safe method for reducing pollutants has gained more attention. However, the contribution of such by-product to the improvement of the pharmacological properties addressing the health benefits of Scenedesmus sp., as a cosmetic remedy or food ingredient, is not sufficiently available. To address this issue, Scenedesmus sp. was cultivated in BG11 medium enriched or not with 20% of ultra-filtrated olive mill wastewater (UFOMW) and polyphenols were then extracted, identified, and quantified by HPLC–DAD analysis. Their antioxidant capacity, enzymatic inhibition, potential in inhibiting lysozyme aggregation, B16 and HeLa cell proliferation, cytotoxic effect against healthy cells, and their intracellular anti-melanogenic effect were assessed, up to our knowledge, for the first time in this study. The addition of UFOMW enhanced the production and apparition of some phenolic compounds with low cytotoxicity on normal versus cancer cells. UFOMW improved the antioxidant capacity and promoted melanogenesis, enzyme, and lysozyme inhibition. Interestingly, Scenedesmus sp. cultured in the presence of UFOMW may provide a valuable source of safe antioxidants with an enhanced biological potential that can be commercially exploited in the food and/or pharmaceutical industries. [ABSTRACT FROM AUTHOR]

The present study aimed to isolate a bioflocculating fungal strain from wastewater collected from a local bike garage. The isolate showed maximum similarity to Aspergillus species. The fungus was identified as Aspergillus flavus species F_GTAF1 IU (accession no OP703382). The isolated fungus was evaluated in terms of biomass recovery efficiency in Scenedesmus Sp. GTAF01. The extent of algal fungal co-pelletization was evaluated as a function of the algae-to-fungi ratio, volume of fungal culture in broth, agitation rate, and pH. results showed that at fungal culture volume of 60░%v/v, fungal culture volume of 1:3░%w/w, 100 rpm, and pH 3, 93.6░% biomass was obtained during the initial 5 h. At wavenumbers 1384 and 1024 cm-1 a significant alteration in the transmission percentage was observed in co-pellet compared to algae and fungal cells. This shows the significant role of C-H–H and C-N stretches in co-pellet formation. This study provides deep insight into effective microalgal harvesting along with the simultaneous extraction of lipids that can be used for the sustainable production of biodiesel.

Nearly 57 million people depend on Yamuna's water for their daily needs and agriculture. This is the first study of assessment of the Yamuna River for five major pollutants – Nitrate, Sulfate, Phosphate, Silicon, and Chloride, and the role of inhabitant algal species for phycoremediation. Water samples were collected from 11 different locations across three different seasons and it was found that the concentration of these pollutants varies in different locations and seasons. The concentration of Nitrate 392.93 mg/L at ITO Monsoon 2021, Phosphate 86.25 mg/L at Baghpat, Silicon 257.34 mg/L at Faridabad, Sulfate 2165.949 mg/L at ITO during winter 2020, and Chloride 4400.741 mg/L at Old bridge during Monsoon 2021 are found maximum. A significant variation (p < 0.05) in the concentrations of Nitrate, Sulfate, Phosphate, Silicon, and Chloride before and after treatment with microalgae was observed in water samples. All six algae significantly remove all the pollutants, and the maximum pollutants removed are Phosphate and Nitrite. Scenedesmus sp., removes the highest 99.21% Phosphate and 86.31% Nitrate, whereas 78.50% of Sulfate was removed by Klebsormidium sp. The highest 92.77% Silicon and 86.20% Chloride were removed by Oocystis sp. This finding suggests that out of six algae, Scenedesmus sp., in the Yamuna water has grown primarily at all the sites and reduces maximum pollutants. The outcomes from this study confirms that Yamuna River is highly contaminated at all the sites from these five major pollutants and algae are still survive in highly contaminated Yamuna water where no other plants are grown and phycoremediate the water bodies even in the presence of very high-stress condition. These algae can further be utilized for biotreatment of any contaminated water body. This is the first study of assessment of five major pollutants and role of inhabitant algal species of Yamuna River for Phycoremediation. The assessment of five major pollutants and bioremediation ability of intrinsic microalgae Monoraphidium sp., Chlorococcum sp., Scenedesmus sp., Nephrocytium sp., Klebsormidium sp., and Oocystis sp., of the Yamuna River was studied for the first time. Scenedesmus sp., in the Yamuna water, has grown primarily at all the sites and reduce maximum 99.21% Phosphate and 86.31% Nitrate. Klebsormidium sp., removed 78.50% of Sulfate and the highest 92.77% Silicon and 86.20% Chloride was removed by Oocystis sp. [ABSTRACT FROM AUTHOR]

Simple Summary: Alternative feed materials in poultry production are an important tool for sustainability and also improving animal performance, health status, and product quality. Thus, our present study aimed to investigate the usage possibility of algae as an alternative feed ingredient in poultry nutrition. In these regards, this study aimed to evaluate the nutritional value and production cost of three species of algae, namely Scenedesmus sp., Ankistrodesmus sp., and Synechococcaceae, harvested with batch and continuous cultivation processes. The current results clearly showed that the nutritional composition and amino acid profile of algae biomass harvested from three different microalgae species under batch and continuous cultivation practices are relatively higher and show variations in protein and lipid content. The current findings indicate the superiority of Scenedesmus sp. for its high PUFA and lysine content, and Synechocccaceae for its high content of methionine and threonine. Furthermore, Synechococcaceae could be offered as a natural additive for the pigmentation of egg yolk and broiler meat due to its darker shade of yellowness. It is important to emphasize that the nutritional value and production cost of microalgae must be considered to choose the right one as an alternative feedstuff. Recently, the demand for new alternative feedstuffs that do not contain chemical residue and are not genetically modified has been increased for sustainability in poultry production. In this respect, the usage of algae as animal feed is very promising as an alternative feed ingredient that reduces pollutant gases from animal production facilities. The aim of the current study is to investigate the usage possibility of algae, through determining nutritional value and production cost, as a feed ingredient in poultry nutrition. Three microalgae species, including Scenedesmus sp., Ankistrodesmus sp., and Synechococcaceae, were produced with batch and continuous cultivation to determine the difference in the lipid, protein, carbohydrate, fatty acid, and amino acid profiles, as well as the color characteristics and production cost. The highest lipid content of 72.5% was observed in algae biomass produced from Synechococcaceae with batch cultivation, whereas the highest protein level was found in algae biomass produced by Synechococcaceae under continuous cultivation practice (25.6%). The highest content of PUFA was observed in Scenedesmus sp. harvested from both batch and continuous cultivation (35.6 and 36.2%), whereas the lowest content of PUFA was found in Synechococcaceae harvested with continuous cultivation (0.4%). Continuously cultivated of Scenedesmus sp. had higher carbohydrate content than batch-cultivated Scenedesmus sp. (57.2% vs. 50.1%). The algae biomass produced from Synechococcaceae was found to have a higher content of essential amino acids, except lysine and histidine, compared to Scenedesmus sp. and Ankistrodesmus sp. Cultivation practices also affected the amino acid level in each algae species. The continuous cultivation practice resulted in a higher level of essential amino acids, except glycine. Synechococcaceae had richer essential amino acid content except for proline and ornithine, whereas continuous cultivation caused an incremental increase in non-essential amino acids. The lightness value was found to be the lowest (13.9) in Scenedesmus sp. that was continuously cultivated. The current study indicated that Scenedesmus sp. could be offered for its high PUFA and lysine content, whereas Synechococcaceae could have potential due to its high content of methionine and threonine, among the investigated microalgae and Cyanobacteria. [ABSTRACT FROM AUTHOR]

Microalgae have the ability to utilize nutrients present in wastewater and generate biomass that is abundant in carbohydrates, lipids, and proteins. The ability of microalgae to integrate wastewater management and biofuel production makes them a promising solution for enhancing environmental sustainability. The objective of this study was to assess the potential of local microalgae, Scenedesmus sp., to simultaneously remediate wastewater and produce lipids. The microalgae were cultivated in anaerobically digested brewery effluent, both sterilized and non-sterilized, to evaluate their phycoremediation and lipid production capabilities. The phycoremediation study was investigated by measuring chemical oxygen demand (COD), total nitrogen (TN), ammonium–nitrogen (NH4+-N), and total phosphorus (TP) removal from brewery effluent. Lipids were extracted from microalgal biomass without and with pretreatment methods, such as microwave, autoclave, osmotic stress, oven heating, and HCl digestion in a water bath, to enhance lipid extraction. Results indicate that Scenedesmus sp. achieves higher biomass production in non-sterilized brewery effluent compared to sterilized brewery effluent. Conversely, it attains higher lipid accumulation in sterilized brewery effluent compared to non-sterilized brewery effluent. Scenedesmus sp. also attained a higher removal of TP (69.32%) and COD (77.78%) in non-sterilized effluent, but TN (96.14%) in sterilized brewery effluent. The removal of NH4+-N was nearly 100% in both effluents. The maximum lipid content obtained was 14.79%, which was enhanced by 39.06%, 23.89%, 15.81%, 11.61%, and 4.78% after microwave, HCl digestion, autoclave, osmotic, and oven heating pretreatments, respectively. The findings of this study demonstrate that local microalgae have a great potential for wastewater remediation with lipid production using appropriate pretreatment methods. [ABSTRACT FROM AUTHOR]

The demands for alternative fuel sources rapidly riring due to depleting fossil fuel sources and severe environmental impacts of using them aggressively. The current study investigates and compares the performance of the third generation Scenedesmus sp. and second generation Pongamia blended biodiesels and the impacts of mixing cerium oxide (CeO 2) nanoadditives on the performace and emission charactestics. Enriched percentage of biodiesel: thirty percent blended biodiesels of Scenedesmus sp. (A30), Pongamia (P30), 100 ppm CeO 2 nanoparticles in A30 (A30C100), and 100 ppm CeO 2 nanoparticles in P30 (P30C100) are experimentally tested in an indirect injection CI engine. Nanoparticle addition to Scenedesmus sp. and Pongamia biodiesel blends improved the engine average brake thermal efficiency (BTE) by 4.2% and 3.8% respectively. The peak pressures are found to be the highest for nanoparticle-added blends and their peak heat release rates are slightly shifted from the top dead center. The A30 and P30 NOx emissions are found to be lower than the diesel, addition of nanoparticles increased the NOx emission level by 2.17% and 6.17% respectively. The average NOx emission of P30C100 is found even higher than diesel. Smoke emissions of all biodiesel variants tested in the current study are found to be significantly lower than diesel. The addition of CeO 2 nanoparticles helped in improving the performance of blended biodiesel and reducing the smoke emissions of an engine. Scenedesmus biodiesel-nanoparticle blend (A30C100) achieved BTE close to diesel at higher loads and it is recommended as a better alternative fuel for CI engines. The findings of the current study will help in exploring the ways of shifting from B20 to B30 in many fleet and commerical vehicles. [Display omitted] • Comparison of FA profile of Scenedesmus sp. and Pongamia biodiesel. • Cerium oxide nanoparticle mixing in blends of Scenedesmus sp. and Pongamia. • Scenedesmus -nanoparticle blend had similar BTE to diesel at high loads. • NOx emission increased by addition of nanoparticles. • Tremendous smoke emission reduction by blends with and without nanoparticles. [ABSTRACT FROM AUTHOR]

In the recent past, various microalgae have been considered a renewable energy source for biofuel production, and their amount and extent can be enhanced by applying certain types of stress including salinity. Although microalgae growing under salinity stress result in a higher lipid content, they simultaneously reduce in growth and biomass output. To resolve this issue, the physiochemical changes in microalgae Scenedesmus sp. BHU1 have been assessed through two-stage cultivation. In stage-I, the maximum carbohydrate and lipid contents (39.55 and 34.10%) were found at a 0.4 M NaCl concentration, while in stage-II, the maximum carbohydrate and lipid contents (42.16 and 38.10%) were obtained in the 8-day-old culture. However, under increased salinity, Scenedesmus sp. BHU1 exhibited a decrease in photosynthetic attributes, including Chl-a, Chl-b, Fv/Fm, Y(II), Y(NPQ), NPQ, qP, qL, qN, and ETRmax but increased Y(NO) and carotenoids content. Apart from physiological attributes, osmoprotectants, stress biomarkers, and nonenzymatic antioxidants were also studied to elucidate the role of reactive oxygen species (ROS) facilitated lipid synthesis. Furthermore, elemental and mineral ion analysis of microalgal biomass was performed to evaluate the biomass quality for biofuel and cell homeostasis. Based on fluorometry analysis, we found the maximum neutral lipids in the 8-day-old grown culture at stage-II in Scenedesmus sp. BHU1. Furthermore, the use of Fourier-transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy analyses confirmed the presence of higher levels of hydrocarbons and triacylglycerides (TAGs) composed of saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) in the 8-day-old culture. Therefore, Scenedesmus sp. BHU1 can be a promising microalga for potential biodiesel feedstock. [ABSTRACT FROM AUTHOR]

Microalgae are considered natural alternatives to replace synthetic antioxidants. The extraction of polyphenols from Scenedesmus sp. and Chlorella sp. was optimized by employing a central composite design. The effect of solvent nature (ethanol, methanol, and ethyl acetate), extraction temperature (4–80 °C), and extraction time (0.1–4 h) were investigated with an ultrasound-assisted system. Total phenolic compound (TPC) extraction was higher at the combination of methanol, 4 °C, and 4 h for Scenedesmus and methanol, 80 °C, and 4 h for Chlorella. Microalgae were cultivated in BG11 and BG11 + 40% olive mill wastewater (OMUF) media. The extracts were analyzed for their total polyphenol content and antioxidant and antimicrobial activities. The estimation results of models and experimental results indicated a high consistency when cultivating microalgae in BG11 medium. Polyphenols extracted from microalgae cultured with 40% (OMUF) possess significantly high antioxidant and antimicrobial activities. Hence, Scenedesmus sp. and Chlorella sp. showed a capability to grow in the presence of ultrafiltered OMW and produce high added-value compounds. [ABSTRACT FROM AUTHOR]

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BACKGROUND: With the rapid development of modern industry and agriculture, large amounts of sewage of various types are being discharged into water bodies every year, causing huge environmental pressure and posing a threat to organisms. Amongst different solutions to this problem, microalgae can remove pollutants including pesticides and antibiotics from water. In this work, an algal strain designated as Scenedesmus sp. TXH. was isolated from the Tangxun Lake Sewage Treatment Plant (Wuhan, China) and used to remove imidacloprid (IMI) from sewage. The removal efficiency, degradation products, removal of conventional contaminants [total dissolved nitrogen (TDN) ammonia nitrogen (NH4+‐N), total dissolved phosphorus (TDP)], the biochemical response of the microalgae, and the effects of environmental factors such as light intensity and temperature were investigated. RESULTS: The results showed that: (i) the highest IMI removal efficiency of ≈60% was achieved under 80 μmol m−2 s−1 at 25 °C; (ii) the removal of NH4+‐N, TDP and TDN in the sewage reached 90%, 90% and 65%, respectively; (iii) there was a significant linear relationship between the concentration of total chlorophyll and the removal of IMI in the sewage; and (iv) finally, based on the analysis of degradation products by mass spectrometer, three potential IMI degradation pathways were proposed. CONCLUSION: In summary, our results showed that Scenedesmus sp. TXH can remove IMI and conventional nutrients efficiently from sewage, implying a potential application in sewage treatment in the near future. © 2023 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Attached cultivation system has emerged as a cost-effective approach for the cultivation of microalgae. However, few microalgae species are still restricted to grow as biofilm due to the lack of adhesive element known as extracellular polymeric substance (EPS). The main objective of our study is to develop a novel attached cultivation strategy for EPS-lacking microalgae, Scenedesmus sp. DDVG I. We also aimed to identify cost-effective substratum showing good performance for biofilm growth. The approach was experimentally studied by conditioning a variety of substrata with EPS derived on varying days from cyanobacteria, Limnothrix sp. DDVG II. The EPS-coated substrata were used for the attached cultivation system of Scenedesmus sp. Additionally, we compared the biochemical properties of the EPS matrix derived on varying days using different extraction methods, their performance on adhesion strength, and microalgal growth. As a result, rough substrata were highly prone to the colonization of the EPS matrix than the normal one. The EPS derived from 12-day-old Limnothrix sp. culture (EPS-12) showed the highest potential on adhesion strength. Rough substrata coated with EPS-12 showed the maximum growth of Scenedesmus sp. DDVG I as a biofilm. Among the rough substrata, rough polylactic acid (rPLA) sheet coated with EPS-12 was found to be the best substratum showing the highest adhesion capability of 94.60 ± 4.2% and the maximum aerial biomass productivity of 31.6 ± 1.20 g/m2/day. The results indicate that EPS-lacking Scenedesmus sp. can be cultured with the attached cultivation technique to improve its biomass productivity. [ABSTRACT FROM AUTHOR]

Recently, the demand for new alternative feedstuffs that do not contain chemical residue and are not genetically modified has been increased for sustainability in poultry production. In this respect, the usage of algae as animal feed is very promising as an alternative feed ingredient that reduces pollutant gases from animal production facilities. The aim of the current study is to investigate the usage possibility of algae, through determining nutritional value and production cost, as a feed ingredient in poultry nutrition. Three microalgae species, including Scenedesmus sp., Ankistrodesmus sp., and Synechococcaceae, were produced with batch and continuous cultivation to determine the difference in the lipid, protein, carbohydrate, fatty acid, and amino acid profiles, as well as the color characteristics and production cost. The highest lipid content of 72.5% was observed in algae biomass produced from Synechococcaceae with batch cultivation, whereas the highest protein level was found in algae biomass produced by Synechococcaceae under continuous cultivation practice (25.6%). The highest content of PUFA was observed in Scenedesmus sp. harvested from both batch and continuous cultivation (35.6 and 36.2%), whereas the lowest content of PUFA was found in Synechococcaceae harvested with continuous cultivation (0.4%). Continuously cultivated of Scenedesmus sp. had higher carbohydrate content than batch-cultivated Scenedesmus sp. (57.2% vs. 50.1%). The algae biomass produced from Synechococcaceae was found to have a higher content of essential amino acids, except lysine and histidine, compared to Scenedesmus sp. and Ankistrodesmus sp. Cultivation practices also affected the amino acid level in each algae species. The continuous cultivation practice resulted in a higher level of essential amino acids, except glycine. Synechococcaceae had richer essential amino acid content except for proline and ornithine, whereas continuous cultivation caused an incremental increase in non-essential amino acids. The lightness value was found to be the lowest (13.9) in Scenedesmus sp. that was continuously cultivated. The current study indicated that Scenedesmus sp. could be offered for its high PUFA and lysine content, whereas Synechococcaceae could have potential due to its high content of methionine and threonine, among the investigated microalgae and Cyanobacteria.

BACKGROUND: With the rapid development of society, a large amount of wastewater and pesticides enter the water bodies globally, posing a threat to both the environment and the health of people and other living things. In this paper, an algal strain Scenedesmus sp. was isolated from a municipal wastewater treatment plant (WWTP); its interaction effect with wastewater bacteria on the removal of IMI and conventional pollutants in municipal wastewater was evaluated. RESULTS: In this study, an algae‐bacteria system was constructed with municipal wastewater, with the aim of exploring the removal effects and mechanisms of the consortium system on Imidacloprid (IMI, 20 mg L−1 and 60 mg L−1) and conventional nutrients from municipal wastewater. The results showed that no IMI was removed under 20 μmol m−2 s−1. However, under 60 μmol m−2 s−1, more than 90% of IMI was removed in the algae‐wastewater group (AWG) with Scenedesmus sp.; this value is much higher than the 50.4% (20 mg L−1) and 36.1% (60 mg L−1) achieved by the wastewater group (WG) without Scenedesmus sp. Meanwhile, the removal efficiency of nitrogen was 82.3% (20 mg L−1) and 71.9% (60 mg L−1) in AWG, both of which are higher than the 73.4% and 59.1% in WG, respectively. Moreover, Scenedesmus sp. TXH has a strong resistance to IMI and 4 degradation products (including IMI‐urea, 4(5)‐hydroxy‐IMI, Nitrosimine, and a substance with m/z of 176) were found in AWG. CONCLUSION: Using consortium to treat municipal wastewater containing IMI is an effective and safe way. © 2022 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Microalgae are vital for their photosynthetic abilities, contributing significantly to global oxygen production, serving as a key trophic level in aquatic ecosystems, aiding in biofuel production, assisting in wastewater treatment, and facilitating the synthesis of valuable biochemicals. Despite these advantages, photosynthetic microalgae are sensitive to salt stress, which alters their physiochemical and metabolic status, ultimately reducing microalgal growth. This sensitivity highlights the importance of understanding the impact of elevated salt content on the physiochemical, metabolic, and transcriptomic profiling of Scenedesmus sp., areas that are not yet fully understood. Our findings indicate that elevated salt stress decreases photosynthetic efficiency and increases non-regulated photochemical quenching of photosystem II (PSII). Moreover, PSII-driven linear electron flow (LEF) decreased, whereas photosystem I (PSI)-driven cyclic electron flow (CEF) increased in salt-stressed cells. To better understand the electron flow from PSII to PSI under elevated salt treatment, we analyzed the excitation energy flux per reaction center (RC), per cross-section (CS), energy flux ratios, and the potential index of PSII. Additionally, flow cytometry graphs depict the viability assay of Scenedesmus sp. BHU1. Our observations further revealed an increase in biochemical attributes, such as stress biomarkers, osmoprotectants, and enzymatic antioxidants, which help scavenge reactive oxygen species (ROS) under salt stress. Intracellular cations (Na  +  and Ca 2+ ) were increased, while K + levels decreased, indicating mechanisms of cellular homeostasis under salt stress. UHPLC-HRMS-based lipidome analysis confirmed that increasing salt stress induces the hyperaccumulation of several fatty acids involved in adaptation. Moreover, transcriptome analysis revealed the upregulation of genes associated with PSI, glycolysis, starch metabolism, sucrose metabolism, and lipid accumulation under salt stress. In contrast, genes related to PSII and C3 carbon fixation were downregulated to mitigate the adverse effects of salt stress., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Singh, Yadav, Sharma, Kumar, Hashem, Abd_Allah and Gupta.)

In the recent past, various microalgae have been considered a renewable energy source for biofuel production, and their amount and extent can be enhanced by applying certain types of stress including salinity. Although microalgae growing under salinity stress result in a higher lipid content, they simultaneously reduce in growth and biomass output. To resolve this issue, the physiochemical changes in microalgae Scenedesmus sp. BHU1 have been assessed through two-stage cultivation. In stage-I, the maximum carbohydrate and lipid contents (39.55 and 34.10%) were found at a 0.4 M NaCl concentration, while in stage-II, the maximum carbohydrate and lipid contents (42.16 and 38.10%) were obtained in the 8-day-old culture. However, under increased salinity, Scenedesmus sp. BHU1 exhibited a decrease in photosynthetic attributes, including Chl-a, Chl-b, Fv/Fm, Y(II), Y(NPQ), NPQ, qP, qL, qN, and ETRmax but increased Y(NO) and carotenoids content. Apart from physiological attributes, osmoprotectants, stress biomarkers, and nonenzymatic antioxidants were also studied to elucidate the role of reactive oxygen species (ROS) facilitated lipid synthesis. Furthermore, elemental and mineral ion analysis of microalgal biomass was performed to evaluate the biomass quality for biofuel and cell homeostasis. Based on fluorometry analysis, we found the maximum neutral lipids in the 8-day-old grown culture at stage-II in Scenedesmus sp. BHU1. Furthermore, the use of Fourier-transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy analyses confirmed the presence of higher levels of hydrocarbons and triacylglycerides (TAGs) composed of saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) in the 8-day-old culture. Therefore, Scenedesmus sp. BHU1 can be a promising microalga for potential biodiesel feedstock.

A salt-tolerant microalga was screened from a moderately-slightly saline soil in the Guanzhong plain and was identified as Scenedesmus sp. by molecular biology sequencing. The effects of different degrees of salt stress (5 g/ L, 10 g/L, 15 g/L and 20 g/ L NaCl) on the growth, physiological characteristics and cell structure of Scenedesmus sp. were studied. The results showed that the chlorophyll synthesis of Scenedesmus sp. was inhibited under salt stress,and the inhibitory effect became more obvious with increased NaCl concentration. At the same incubation time, the superoxide dismutase (SOD) activity, malondialdehyde ( MDA), soluble protein and extracellular polysaccharide (EPS) contents of Scenedesmus sp. were lower at low salt concentration than those at high salt concentration, but all were significantly higher than the control trea tment CP< O. 05). Under the same salt concentration, the SOD activity, MDA and soluble protein contents increased first and then decreased in the continuous culture process, while the EPS content continued accumulating. Optical microscope and scanning electron microscope CSEM) observations showed that the cell walls of Scenedesmus sp. were smooth, with thorns, teeth or ridges, and arranged in a fence or quadrangular shape under the control treatment, while under high salt stress (20 g/ L NaCl), the surface of cells appeared wrinkled and damaged, the cells changed from fence-shaped or quadrangular to round-shaped, and the algae are more densely distributed. [ABSTRACT FROM AUTHOR]

Sustainable material sources are an important agenda to protect the environment and to meet human needs. In this study, Scenedesmus sp. was used to treat municipal landfill leachate via batch and continuous cultivation modes to protect the environment and explore sufficient biomass production for bioethanol production using Saccharomyces cerevisiae. Physicochemical characteristics of leachate were determined for the phases before, during, and after the process. Batch and continuous cultivation were used to treat raw leachate to determine optimum conditions for treatment. Then, the biomass of Scenedesmus sp. with and without sonication was used as a substrate for ethanol production. Sonication was carried out for biomass cell disruption for 20 min at a frequency of 40 kHz. Through batch cultivation mode, it was found that pH 7 was the optimum condition for leachate treatment. Continuous cultivation mode had the highest removal values for COD, phosphorus, and carbohydrate, namely 82.81%, 79.70%, and 84.35%, respectively, among other modes. As for ethanol production, biomass without sonication with 9.026 mg·L−1 ethanol, a biomass concentration of 3.300 µg·L−1, and pH 5 were higher than biomass with sonication with 5.562 mg·L−1 ethanol, a biomass concentration of 0.110 µg·L−1, and pH 5. Therefore, it is evident that the leachate has the potential to be treated by Scenedesmus sp. and converted to bioethanol in line with the concept of sustainable materials. [ABSTRACT FROM AUTHOR]

In the present study, different microalgae were isolated from wastewater environment and evaluated for higher growth and lipid accumulation. The growth adaptability of all the isolated microalgae were tested for carbon source with supplementation of sodium bicarbonate in BG-11 N+ medium. Further based on the uptake rate of sodium bicarbonate and growth behavior, microalgal strains were selected for biofuel feedstock. During the study, growth parameters of all the isolates were screened after supplementation with various carbon sources, in which strain Scenedesmus sp. BHU1 was found highly effective among all. The efficacy of Scenedesmus sp. BHU1 strain under different sodium bicarbonate (4–20 mM) concentration, in which higher growth 1.4 times greater than control was observed at the concentration 12 mM sodium bicarbonate. In addition, total chlorophyll content (Chl-a + Chl-b), chlorophyll fluorescence (Fv/Fm, Y(II), ETR max, and NPQmax), and biomass productivity were found to be 11.514 μg/ml, 0.673, 0.675, and 31.167 μmol electrons m−2 s−1, 1.399, 59.167 mg/L/day, respectively, at the 12 mM sodium bicarbonate. However, under optimum sodium bicarbonate supplementation, 56.920% carbohydrate and 34.693% lipid content were accumulated, which showed potential of sodium bicarbonate supplementation in renewable biofuel feedstock by using Scenedesmus sp. BHU1 strain. [ABSTRACT FROM AUTHOR]

This paper explores the ability of Chlorella sp. and Scenedesmus sp. to convert landfill leachates into usable metabolites. Different concentrations (0.5, 1, 5, and 10% v/v) of leachate coupled with an inorganic carbon source (Na2CO3, and NaHCO3) were tested to improve biomass production, metabolites synthesis, and removal of NO3 and PO4. The result shows that both strains can effectively grow in media with up to 5% (v/v) leachate, while significantly reducing the concentrations of NO3, and PO4 (80 and 50%, respectively). The addition of NaHCO3 as a carbon source improved the final concentration of biomass, lipids, carbohydrates, and the removal of NO3 and PO4 in both strains. [ABSTRACT FROM AUTHOR]

In the present study, the conditions for an autotrophic and mixotrophic culture of Scenedesmus sp were established. Effluents from acidic coal mine drains were used to study biomass and carotenoid production, both under autotrophic and mixotrophic conditions in relation to the effect of different sources of nitrogen: sodium nitrate, urea and ammonium phosphate. Pollutant removal was determined, such as COD, TOC, heavy metals, ions and total suspended solids. Batch cultures lasted nine days and biomass production, carotenoids and pollutant removal were compared in each condition. The highest biomass concentration reached was 1.2 g/L in the mixotrophic culture with urea, followed by the culture with sodium nitrate of 0.9 g/L in a C/N ratio of 6:1. The highest carotenoid specific concentration was reached in the mixotrophic culture with sodium nitrate, 19.43 mg carotenoids/g biomass. The culture with ammonium phosphate was found to be inhibitory for the growth of the microalgae with the lowest results of all the parameters except for the autotrophic culture where the concentration of carotenoids was very similar to those reached with sodium nitrate and urea. Finally, the mixotrophic culture with urea presented the highest removal percentages, being 86.97% for total iron, 58.29% for chlorides and 92.5% for COD. [ABSTRACT FROM AUTHOR]

Abstract Background The combination of nutrient removal using microalgae from wastewater with carbohydrate production has been considered as a promising approach for sustainable wastewater treatment and production of valuable products such as biofuels. In Ethiopia, urbanization and industrial development are not in tandem with wastewater treatment system The objective of this study was to evaluate nutrient removal and carbohydrate production potential of the indigenous microalgae Scenedesmus sp. grown in anaerobically digested brewery wastewater. The indigenous Scenedesmus sp. was grown in an anaerobically digested brewery effluent in different seasons of the year. The biomass was converted into carbohydrate using microwave, autoclave, and oven as pretreatment, followed by optimization for acid concentrations and hydrolysis time. Result The overall removal efficiencies for the indigenous Scenedesmus sp. based wastewater treatment system were over 99%, 92%, 63%, 65% and 75% for NH4 +-N, TN, PO4 3− -P, TP and COD, respectively. The concentrations of final effluent quality of these parameters except for phosphorus nutrient were below the permissible discharge limit for brewery effluent standard set by Ethiopian Environmental Protection Authority. With regard to carbohydrate production, microwave-assisted acid hydrolysis with HCl produced a higher total sugar than that of autoclave and oven pretreatments. Among acid concentrations, HCl with 3 N produced a higher total sugar, which is significantly different (P

In the present study, different microalgae were isolated from wastewater environment and evaluated for higher growth and lipid accumulation. The growth adaptability of all the isolated microalgae were tested for carbon source with supplementation of sodium bicarbonate in BG-11 N+ medium. Further based on the uptake rate of sodium bicarbonate and growth behavior, microalgal strains were selected for biofuel feedstock. During the study, growth parameters of all the isolates were screened after supplementation with various carbon sources, in which strain Scenedesmus sp. BHU1 was found highly effective among all. The efficacy of Scenedesmus sp. BHU1 strain under different sodium bicarbonate (4–20 mM) concentration, in which higher growth 1.4 times greater than control was observed at the concentration 12 mM sodium bicarbonate. In addition, total chlorophyll content (Chl-a + Chl-b), chlorophyll fluorescence (Fv/Fm, Y(II), ETR max, and NPQmax), and biomass productivity were found to be 11.514 μg/ml, 0.673, 0.675, and 31.167 μmol electrons m−2 s−1, 1.399, 59.167 mg/L/day, respectively, at the 12 mM sodium bicarbonate. However, under optimum sodium bicarbonate supplementation, 56.920% carbohydrate and 34.693% lipid content were accumulated, which showed potential of sodium bicarbonate supplementation in renewable biofuel feedstock by using Scenedesmus sp. BHU1 strain.

The present study aimed to isolate a bioflocculating fungal strain from wastewater collected from a local bike garage. The isolate showed maximum similarity to Aspergillus species . The fungus was identified as Aspergillus flavus species F&#95;GTAF1 IU (accession no OP703382). The isolated fungus was evaluated in terms of biomass recovery efficiency in Scenedesmus Sp. GTAF01. The extent of algal fungal co-pelletization was evaluated as a function of the algae-to-fungi ratio, volume of fungal culture in broth, agitation rate, and pH. results showed that at fungal culture volume of 60 ░ %v/v, fungal culture volume of 1:3 ░ %w/w, 100 rpm, and pH 3, 93.6 ░ % biomass was obtained during the initial 5 h. At wavenumbers 1384 and 1024 cm -1 a significant alteration in the transmission percentage was observed in co-pellet compared to algae and fungal cells. This shows the significant role of C-H-H and C-N stretches in co-pellet formation. This study provides deep insight into effective microalgal harvesting along with the simultaneous extraction of lipids that can be used for the sustainable production of biodiesel., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

BACKGROUND The three‐phase extraction process of olive oil produces highly contaminated wastewater (OMW). The elimination of this toxic by‐product is an important environmental issue that requires the development of an appropriate management solution. The cultivation of microalgae using OMW as growth medium was therefore studied using single (the culture medium was formed by 0% to 80% ultrafiltered olive mill wastewater (OMUF) or OMW added to BG11) and two‐stage strategies (microalgae were firstly cultivated in the BG11 medium. In the second stage, 40% and 80% of OMUF and OMW were added to the culture). In this work, biodegradation of OMW and subsequent extraction of lipid and antioxidant molecules was investigated as an ecofriendly method for the bioremediation and valorization of OMW. RESULTS: For two‐stage cultivation, OMUF and OMW stress enhanced the intracellular amount of polyphenol accumulated in Scenedesmus sp. and exhibited the highest 2, 2‐diphenyl−1‐ picrylhydrazyl radical (DPPH) and 2,2'‐azino‐bis (3‐ethylbenzoline‐6‐sulfonate) radical (ABTS) scavenging ability compared with single‐stage cultivation. Moreover, the lipid profile is dominated by polyunsaturated acids. In the single‐stage cultivation, the Ch a, Ch b, carotenoid, carbohydrate and lipid content of 2.57, 7.4, 1.69, 368, and 644 g kg−1 were observed in 40% OMUF added culture, respectively, along with high biomass productivity and 58% of polyphenol removal. Moreover, the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT) assay showed that the biomass of Scenedesmus sp. cultured on 40% OMUF did not show any toxic effect, making it an efficient strategy. CONCLUSION: The results indicate that Scenedesmus sp. is a promising microalga for the biotreatment of OMW and the extraction of bioactive metabolites. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Mitigating CO 2 emissions emerges as a crucial focal point within the current environmental and health challenges. In order to evolve to a net-zero future, it is noteworthy that a photosynthetic microalga demonstrates resilience to CO 2 stress modulations, thereby efficiently navigating the production of essential bioproducts. RuBisCO, an enzyme responsible for capturing and partitioning CO 2 by photosynthetic microalgae, acts differently under varying environmental perturbations, thus affecting its central carbon metabolism. With the target of unraveling the carbon partitioning machinery driven by photosynthetic CO 2 for the production of essential bio-commodities such as lipids, tocopherols, phytosterols, etc., along with efficacious CO 2 sequestration, an investigation has been carried out for the augmentation of overall growth and bioproduct yield of the Scenedesmus sp. The current work aims to understand the metabolomic and physiological consequences occurring within Scenedesmus sp. under the influence of high CO 2 (5 % CO 2) and air-CO 2 (0.04 %), together with different engineered nutrient media. Our results demystify that under the supplementation of elevated CO 2 in Scenedesmus sp., the carbon flux gets diverted towards the accumulation of fatty acids, namely, DHA, EPA, phytosterols, and α-tocopherol in conjunction with the increase in the biomass content (42 %). Furthermore, the qualitative untargeted metabolomics performed by GC–MS identified nearly 67 metabolites, among which significant fold change has been ascertained for the production of sugars, fatty acids, alcohols, etc., under the impact of 5 % CO 2 compared to air-CO 2. Eventually, the goal is to comprehend metabolic modulations and photosynthetic carbon partitioning occurring within microalgal cell factories by scrutinizing metabolome regulations for invigorating the path of carbon neutrality. The work focuses on developing a sustainable technology for regulating and mitigating greenhouse gas, i.e., CO 2 emissions, on a commercial scale. • Elevated CO 2 emissions contribute to global warming and human health exclusively. • Scenedesmus sp. mitigate CO 2 by a CCM, thus aiming for carbon neutrality. • Scenedesmus sp. can survive under fertilizer-based and VFAs-based nutrient wastewater. • Metabolites like EPA, DHA, α-Tocopherol, and phytosterols were produced in 5 % CO 2. • Reallocation of carbon flux under air-CO 2 and 5 % CO 2 was metabolically comprehended. [ABSTRACT FROM AUTHOR]

Growth comparisons were made between a microalgal consortium and Scenedesmus sp. cultivated in treated wastewater (TWw) enriched with 1 mL·L–1 Bayfolan Forte fertilizer (BM), TWw enriched with (NH4)2HPO4 (PAM), TWw enriched with NH4HCO3 (BCAM), tap water with piggery wastewater (PEM), tap water with piggery wastewater digestate (PDM), and raw wastewater (Ww). Nitrogen (N) content in the media, except for TWw, was adjusted to 80 mg·L–1 N (NH4+-N and NO3–-N). Unconventional low-cost media with lower nutrient contents (BM and TWw) showed adequate productions of biomass and lipids. PEM was the most advantageous medium, showing the highest biomass productivity with the consortium (191.25 ± 6.25 g·L–1·d–1) and a lipid productivity of 36.75 ± 9.90 mg·L–1·d–1. The fatty acid profile was composed mainly of C16 and C18. PAM, PEM, and PDM showed a higher proportion of saturated fatty acids (60%–69%), whereas the composition of unsaturated fatty acids was in the range of 31% to 38%. In PEM and PDM the removal of NH4+ was 100%; however, there were NH4+ losses (as NH3) due to volatilization (46%). Unconventional media, especially Ww, are an option for growing microalgae.

Nghiên cứu nhằm xác định ảnh hưởng của nguồn dinh dưỡng (NPK, Walne và BG11) và liều lượng phân bón NPK (16:16:8) đến tăng trưởng sinh khối tảo Scendesmus sp. Nghiên cứu được thực hiện với hai thí nghiệm gồm so sánh tăng trưởng quần thể tảo nuôi bằng các nguồn sinh dinh dưỡng khác nhau (NPK, BG11 và Walne), và so sánh tăng trưởng quần thể tảo được nuôi ở nồng độ NPK khác nhau. Tảo được bố trí nuôi trong bình thủy tinh 8 L với mật độ ban đầu là 2×106 tb/mL. Ánh sáng được cung cấp từ đèn LED, cường độ chiếu sáng 3000 Lux, thời gian chiếu sáng 24/24, sục khí liên tục trong suốt thời gian thí nghiệm, trong phòng có điều chỉnh nhiệt độ (24,4±0,4 oC). Kết quả cho thấy tảo Scenedesmus sp. nuôi bằng NPK đạt mật độ cực đại là 35,1±1,1×106 tb/mL vào ngày 13 và khối lượng khô là 13,0±1,2 pg/tb, cao hơn so với các nghiệm thức còn lại, hàm lượng protein và lipid lần lượt là 42,9% và 5,0% khối lượng khô. Tảo Scenedesmus sp. đạt mật độ tảo cao nhất (33,2±0,2×106 tb/mL) khi nuôi với liều lượng NPK 50 mg/L sau 13 ngày nuôi. Do đó, phân NPK có thể sử dụng trong nuôi sinh khối tảo Scenedesmus sp. với liều lượng 50 mg/L để đạt mật độ cao nhất.

The high protein contents in green microalgae can be used for the generation of bioactive peptides for feed, food, and health. Many methods are available for the extraction of microalgal protein but they are not easily scalable due to the requirement of special techniques and instruments. In the present work, the nitrogenous component of green microalgae Chlorella vulgaris and native species Scenedesmus sp. were quantified by the Lowry method and their amino acid composition was analyzed and compared. Proteins extraction was done by milling algal biomass, solubilization at various concentrations of NaOH, and precipitation at acidic pH. In results, both Scenedesmus sp. and C. vulgaris showed the maximum specific growth rate i.e. 0.653 and 0.589 g L-1 d-1, respectively in Bold's Basal Medium. Grinding biomass and then alkaline (1N) treatment at 100 °C for 10 min resulted in the maximum protein extraction from both species. Under optimum conditions, an increase of 19 and 18% in protein contents of Chlorella vulgaris and Scenedesmus sp., respectively compared to control treatment was noted. Regarding amino acid profiling, glutamic and aspartic acids were found in the highest concentrations in Scenedesmus sp. (2.9 and 2.5%) and C. vulgaris (3.2 and 2.8%), respectively. Six amino acids (alanine, aspartic acid, glutamic acid, leucine, lysine, and glycine) were responsible for 50% or more of the total detected amino acid contents in both microalgal species. In conclusion, the consolidating activity of freeze-drying and milling the dry biomass along with alkaline extraction significantly boosted the protein yield. [ABSTRACT FROM AUTHOR]

Growth comparisons were made between a microalgal consortium and Scenedesmus sp. cultivated in treated wastewater (TWw) enriched with 1 mL·L-1 Bayfolan Forte fertilizer (BM), TWw enriched with (NH4)2HPO4 (PAM), TWw enriched with NH4HCO3 (BCAM), tap water with piggery wastewater (PEM), tap water with piggery wastewater digestate (PDM), and raw wastewater (Ww). Nitrogen (N) content in the media, except for TWw, was adjusted to 80 mg·L-1 N (NH4 +-N and NO3 --N). Unconventional low-cost media with lower nutrient contents (BM and TWw) showed adequate productions of biomass and lipids. PEM was the most advantageous medium, showing the highest biomass productivity with the consortium (191.25 ± 6.25 g·L-1·d-1) and a lipid productivity of 36.75 ± 9.90 mg·L-1·d-1. The fatty acid profile was composed mainly of C16 and C18. PAM, PEM, and PDM showed a higher proportion of saturated fatty acids (60%-69%), whereas the composition of unsaturated fatty acids was in the range of 31% to 38%. In PEM and PDM the removal of NH4 + was 100%; however, there were NH4 + losses (as NH3) due to volatilization (46%). Unconventional media, especially Ww, are an option for growing microalgae. [ABSTRACT FROM AUTHOR]

Sustainable material sources are an important agenda to protect the environment and to meet human needs. In this study, Scenedesmus sp. was used to treat municipal landfill leachate via batch and continuous cultivation modes to protect the environment and explore sufficient biomass production for bioethanol production using Saccharomyces cerevisiae. Physicochemical characteristics of leachate were determined for the phases before, during, and after the process. Batch and continuous cultivation were used to treat raw leachate to determine optimum conditions for treatment. Then, the biomass of Scenedesmus sp. with and without sonication was used as a substrate for ethanol production. Sonication was carried out for biomass cell disruption for 20 min at a frequency of 40 kHz. Through batch cultivation mode, it was found that pH 7 was the optimum condition for leachate treatment. Continuous cultivation mode had the highest removal values for COD, phosphorus, and carbohydrate, namely 82.81%, 79.70%, and 84.35%, respectively, among other modes. As for ethanol production, biomass without sonication with 9.026 mg·L−1 ethanol, a biomass concentration of 3.300 µg·L−1, and pH 5 were higher than biomass with sonication with 5.562 mg·L−1 ethanol, a biomass concentration of 0.110 µg·L−1, and pH 5. Therefore, it is evident that the leachate has the potential to be treated by Scenedesmus sp. and converted to bioethanol in line with the concept of sustainable materials.

Scenedesmus species, immobilized on alginate gel, was found effective in removing nitrate, atrazine, magnesium, phosphorus, zinc, oxadiazon, and triallate from groundwater in a continuous flow reactor. The laboratory‐scale experiments with synthetic groundwater, made of 8.8 mg/L NO3‐N and 90 µg/L atrazine, were performed at a hydraulic retention time of 7 days and the temperatures of 20 and 35°C. The highest uptake of nitrate and atrazine was observed at 20°C (97% and 70%, respectively). When tested in actual groundwater, 92% of nitrate, 100% of magnesium, 99.9% of phosphorus, and 92% of zinc were successfully removed at the end of 29 days' treatment operations. The algal beads removed 100% of oxadiazon and triallate in the first 10 days, but some of the herbicides diffused back into the solution toward the end of the treatment process. Practitioner points: Immobilized algae–alginate beads can remove nitrate, atrazine, oxadiazon, and triallate from groundwater in continuous flow reactor.The uptake rate of nitrate and atrazine is higher in room temperature (20°C).Same algae beads could be reused for herbicide uptake for the average of 10 days.The immobilized system is a natural sustainable alternative that can be used in groundwater pump and treat. [ABSTRACT FROM AUTHOR]

Scenedesmus sp. & Chlorella sp., are two isolated microalgae from hot springs located in Norte de Santander, which are studied in order to explore their biotechnological potential. The present work aimed to design a protocol by evaluating two factors, the effect of light radiation stress and incubation time by staggering the culture from box to tube with 20 mL of medium and finally in a 200 mL reactor. From this, in order to obtain a higher production of carotenoids of industrial interest, therefore, a non-factorial central composite surface design was used; As results, it was determined that in Scenedesmus sp microalgae the two factors influence carotenoid deposition and for Chlorella sp the incubation time does not influence and the photoperiod is fundamental in the deposition of these metabolites, on the other hand the program in which evaluated the STATISTICA 7.0 design generates its respective equation from which the optimal incubation time and photoperiod for the studied microalgae were determined. [ABSTRACT FROM AUTHOR]

Meat production is associated with the generation of huge quantities of meat processing wastewater (MPWW) which has high concentrations of nutrients. The utilization of Scenedesmus sp. in the phycoremediation process to treat MPWW has attracted growing interest, but there is inadequate information on the management of biomass of this micro‐organism. This study aims to optimize the harvesting of Scenedesmus sp. biomass generated during phycoremediation through flocculation with alum and its potential biomass by‐product. The removal rates of the chemical oxygen demand, ammonia, total nitrogen, total phosphorus and orthophosphate were 99.16% (R2 = 0.95), 97.19% (R2 = 0.91), 93.91% (R2 = 0.96), 97.25% (R2 = 0.85) and 99.38% (R2 = 0.9517), respectively. From the result, the best coagulant for recovery efficiency (97.54%) was recorded at pH 8.6 with 116.85 mg L−1 alum. Three major chemical compounds – tetradecanoic, oleic and dodecanoic acids – were recorded in the extraction of Scenedesmus sp. biomass (as determined by gas chromatography‐mass spectrometry analysis; these have the potential for use in the cosmetic and medical industries. The main functional groups in the harvested biomass were OH, CH, C‐O‐C and CHCH. It can be concluded that the flocculation method was the most efficient compared to filtration process for recovering Scenedesmus sp. biomass owing to the absence of toxic by‐products. © 2020 Society of Chemical Industry (SCI) [ABSTRACT FROM AUTHOR]

This paper explores the ability of Chlorella sp. and Scenedesmus sp. to convert landfill leachates into usable metabolites. Different concentrations (0.5, 1, 5, and 10% v/v) of leachate coupled with an inorganic carbon source (Na2CO3, and NaHCO3) were tested to improve biomass production, metabolites synthesis, and removal of NO3 and PO4. The result shows that both strains can effectively grow in media with up to 5% (v/v) leachate, while significantly reducing the concentrations of NO3, and PO4 (80 and 50%, respectively). The addition of NaHCO3 as a carbon source improved the final concentration of biomass, lipids, carbohydrates, and the removal of NO3 and PO4 in both strains.

In anaerobic digestion of microalgae, the intracellular material may remain intact due to the non-ruptured membrane and/or cell wall, reducing the methane yield. Therefore, different pretreatment methods were evaluated for the solubilization of microalgae Scenedesmus sp. The anaerobic digestion of biomass hydrolyzed at 150 °C for 60 min with sulfuric acid 0.1% v/v showed higher methane yield (204-316 mL methane/g volatile solids applied) compared to raw biomass (104-163 mL methane/g volatile solids applied). The replacement of sulfuric acid with carbonic acid (by bubbling carbon dioxide up to pH 2.0) provided results similar to those obtained with sulfuric acid, reaching solubilization of 41.6% of the biomass. This result shows that part of the flue gas (containing carbon dioxide and other acid gases as well as high temperatures) may be used for the hydrolysis of the residual biomass from microalgae, thus lowering operational costs (e.g., energy consumption and chemical input).

In attempts to remove toxic metal lead, distinct types of algae biomass have been scrutinized as alternatives to conventional physicochemical technologies. In this research, the absorption of Lead by nanoalgae Scenedesmus sp. was studied at concentration of10 to 100 mg/L, pH 3 to 8, temperature 15 to 40 °C and exposure time of 10 to 60 minutes)in a batch culture system. The concentration of Lead was determined by Atomic absorption spectrometry. Then, the absorption results were described using the Langmuir and Freundlich isotherms and the pseudo-first-order and Pseudo-second-order synthetics and thermodynamic equation of absorption. Optimal adsorption (a removal of 99.13 percent) was obtained at adsorbent amount of 0.05gr, concentration 40mg/L, pH = 4, temperature 30°C and equilibrium time of 20min. At reviews the correlation coefficient, adsorption kinetics follows the pseudo-second-order model and equilibrium is well described by Freundlich isotherm. According to the adsorption thermodynamics, the reaction found to be spontaneous, endothermic and accidentally. FTIR spectrum revealed that functional groups C-O, -OH and -NH played a major role in the adsorption.