Search

Chlorella, a single‐celled green algae rich in proteins, holds promise as a source of bioactive peptides. This research aimed to isolate an antioxidant peptide from Chlorella, examining its stability through digestion. Using Response Surface Methodology (RSM), we identified optimal hydrolysis conditions for Chlorella Protein Hydrolysate (CPH): 55°C, pH 8.75, and an enzyme‐to‐substrate ratio of 2.15%. These conditions led to CPH with notable radical scavenging activity against 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) (53.19 ± 0.99%), 2,2′‐azino‐bis (3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS) (76.86 ± 0.28%), hydroxyl radical (53.39 ± 1.74%), and Fe2+ chelating rates of 22.56 ± 2.97%. Subsequently, peptides under 3 kDa isolated by ultrafication proved particularly stable and antioxidative after in vitro digestion. In addition, further purify to obtain component C1 with DPPH radical scavenging ability of 59.62 ± 1.29% and an Fe2+ chelating ability of 49.78 ± 1.55%. Subsequent LC‐MS/MS identification and virtual screening led to the discovery of a stable and antioxidative peptide, Ser‐Gly‐His‐His‐Lys‐Pro‐Leu (SGHHKPL). The study provides the theoretical basis for the development and utilization of chlorella. [ABSTRACT FROM AUTHOR]

Microalgae are emerging as functional feed ingredients in aquaculture due to their immune-stimulating and stress-modulating properties. We investigated the potential of the microalgae Chlorella vulgaris as a feed supplement to improve the health and modulate microbiota and stress responses of Atlantic salmon. Triplicate groups of Atlantic salmon (~ 126 g) were reared in a recirculating aquaculture system (RAS) at 15 °C and received diets supplemented with 2% (CV2) or 14% (CV14) spray-dried C. vulgaris daily, 14% once weekly (CV14w), or a control diet (CD) for 8 weeks. Subsequently, all groups were exposed to an acute one-hour peracetic acid (CH3CO3H; PAA) treatment, a commonly used disinfectant in RAS. While CV14 increased feed conversion (FCR) significantly, feeding the diets CV2 and CV14w improved protein retention efficiency. CV14 significantly modulated beta-diversity in the intestinal digesta and mucosa, but this effect was already visible in fish fed CV2. Feeding CV14 and, to a lesser degree, CV2 increased the relative abundances of Paenarthrobacter and Trichococcus in the digesta and mucosa, which are able to metabolize complex carbohydrates. However, the same diets reduced the abundance of the lactic acid bacteria Lactobacillus and Weissella in the digesta and Floricoccus in the mucosa. Peracetic acid exposure induced systemic stress (increase in plasma glucose and cortisol) and a local immune response in the gill, with the most prominent upregulation of several immune- and stress-regulated genes (clra, cebpb, marco, tnfrsf14, ikba, c1ql2, drtp1) 18 h after exposure in fish fed the control diet. Fish receiving CV14 once a week showed a reduced transcriptional response to PAA exposure. Catalase protein abundance in the liver increased following exposure to PAA, while superoxide dismutase abundance in the gill and liver was increased in response to C. vulgaris inclusion before stress. Overall, the results highlight that a high (14%) inclusion rate of C. vulgaris in feed for Atlantic salmon impairs feed conversion and shifts the intestinal microbiota composition in digesta and mucosa. Weekly feeding of C. vulgaris proves a viable approach in improving protein retention and improving transcriptional resilience towards oxidative stress in increasingly intensive production systems. Thereby this study may motivate future studies on optimizing temporal feeding schedules for health-promoting aquafeeds. [ABSTRACT FROM AUTHOR]

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The thermodynamic instability of conventional aqueous foam‐stabilized surfactants is a critical bottleneck in the construction of porous materials. Herein, a novel strategy is proposed for preparing a capillary foam based on Chlorella and utilizing it as a template for constructing porous materials with high‐efficiency adsorption. The capillary foam was stabilized by Chlorella particles enclosed within a gel network of oil bridges connecting the particles (capillary suspension). Chlorella particles, which act as stable particles, form oil bridges and are distributed at the phase interface of the capillary foam. These particles exhibited resistance to shear forces, allowing the formation of a long‐term stable capillary foam. Using this foam as a template, a porous material with outstanding adsorption performance for Methylene Blue (MB) and Brilliant Green (BG) dyes was successfully constructed. Additionally, the material exhibited a sustained high adsorption performance even after five thermal regeneration‐adsorption cycles. In conclusion, this study presents a green and straightforward method for constructing capillary foams with high stability, which is a promising approach for developing porous materials with exceptional adsorption and regeneration properties for dyes. [ABSTRACT FROM AUTHOR]

N-glycans have recently emerged as highly varied elements of Chlorella strains and products. Four years and eighty samples later, the increasing N-glycan diversity calls for a re-examination in the light of concepts of species designations and product authenticity. N-glycans of commercial products were analyzed by matrix-assisted time-of-flight mass spectrometry (MALDI-TOF MS) supported by chromatography on porous graphitic carbon with mass spectrometric detection. Although 36% of 172 products were labeled C. vulgaris, only 9% presented what could be taken as a C. vulgaris type N-glycan pattern. Respectively, 5 and 20% of the products matched with C. sorokiniana strains SAG 211-8k and SAG 211-34, which, however, carry entirely different structures. Furthermore, 41% presented with one of four frequently occurring glyco-types while 26% of the samples showed unique or rare N-glycan patterns. These glycan signatures thus profoundly challenge the stated species designations. By no means do we want to question the presumed health benefits of the products or the sincerity of manufacturers. We rather aim to raise awareness of the fascinating but also concerning diversity of microalgal N-glycans and suggest it as a means for defining product identity and taxonomic classifications. [ABSTRACT FROM AUTHOR]

This study focuses on determining the optimum external operating parameters of algal cell lysis for extraction of bio-oil from Chlorella biomass. Response surface methodology has been applied to a regression analysis model for optimizing solvent ratios, i.e., ethyl acetate to ethanol (E.A.:E) ratio for maximum extraction of bio-oil and aqueous deep eutectic solvent to biomass (aDES:biomass) ratio for algal pretreatment for the enhanced yield of bio-oil. Optimized process conditions were 15 min of homogenization combined with ultrasonication (hybrid method). The aDES:biomass ratio of 8.25 caused the highest cell disruption efficiency to liberate bio-oil from encapsulated cells. The solvent ethyl acetate to ethanol ratio (E.A.:E) was optimum at 0.8 for maximum extraction of bio-oil, and studies indicated a maximum bio-oil yield of 94.0% using this hybrid pretreatment process combined with ultrasonication and homogenization. The GC–MS characterization technique was used to analyze the bio-oil, which showed it consisted of 67.93% Di-ethyl phthalate (DEP) and 32.07% esters compounds (C12–C40 hydrocarbons range). The produced DEP from Chlorella biomass using this sustainable green approach is very promising. The estimated cost was around Rs 49 per gm (equivalent to Rs 664.56 for 13.58 gm), which indicates the potential for a cost-effective method to produce pure DEP from Chlorella biomass. [ABSTRACT FROM AUTHOR]

Summary Functionalities of proteins for the formulation of protein‐fortified products are crucial, impacting the use of protein from sustainable sources such as algae. Glycation (the initial step of the Maillard browning reaction) is a standout modification technique explored to improve the functions of the protein in the food matrices. In this study, Chlorella powder was conjugated with inulin using a wet glycation method. It is a quick, scalable and easy method for improving the functionality of food proteins. In this study, conjugation was performed for three different Chlorella to inulin molar ratios (S1:1, S3:1 and S5:1). The solution of each molar ratio was heated at 90°C for 30 min under alkaline state (9.0 pH). Characterisation was conducted employing OPA assay, browning intensity and FTIR spectroscopy techniques. The results suggested glycation achieved the highest for the Chlorella‐inulin ratio of 1:1. Glycation extent influenced the solubility of this conjugate significantly (P < 0.05) under an acidic medium. Other functional properties including hydration, moisture uptake, oil‐binding and emulsifying activity were also significantly (P < 0.05) enhanced compared to unmodified Chlorella powder. Chlorella conjugate with molar ratio 1:1 also displayed higher antioxidant properties suggesting glycation's role in improving Chlorella powder free radical scavenging capabilities (1.25‐fold increase) and reducing power (2.24‐fold increase). The total scavenging activity and total reducing power of S1:1 were 2.526 × 10−3 and 1.872 × 10−3 mg mL−1 mg−1(Trolox Eq.), respectively. The results provide an understanding of different functionalities for glycated conjugates promising utilisation in the food and beverage industry. [ABSTRACT FROM AUTHOR]

In order to investigate the effects of povidone iodine, glutaraldehyde and chlorine dioxide, three commonly used disinfectants in aquaculture, on the growth activity of chlorella, six treatment concentrations were set as 0, 0.25, 0.5, 1.5, 3.0 mg/L and 6.0 mg/L respectively, and the changes of chlorophyll a, biomass, oxygen production and pH of chlorella solution after adding disinfectant were measured. The results showed that compared with the control group, chlorophyllium a, biomass, oxygen production and pH of chloredon showed a trend of first decreasing and then rising with the increase of the three disinfectants, but the inflection point of the recovery time of different disinfectants was different. The effect of chlorine dioxide on chlorella activity was the strongest at the 1st day, but the duration of the effect was short, indicating that it had a strong and rapid inhibitory effect on chlorella. Povidone iodine had the longest effect on chlorella, but the inhibitory effect on chlorella was mild. The inhibitory effect of the three disinfectants on Chlorella activity indexes increased with the increase of the added concentration. Therefore, when the effective disinfection concentration is not higher than 0.25 mg/L in production, it can be used to sprinkle disinfectants several times or reduce the destruction of beneficial algae to the water body, which is conducive to the stability of the algae phase of the aquaculture water body. The results of this study can provide reference for the safe application of disinfectants in aquaculture, and have important reference value for maintaining the stability of beneficial microalgae species in aquaculture water. [ABSTRACT FROM AUTHOR]

This study aimed to assess the effect of a combination of aerobic exercise training (ET) and Chlorella (CH) intake on arterial nitric oxide (NO) production and arterial stiffness in obese rats. Twenty-week-old obese male rats were randomly grouped into four (n = 6): OBESE-SED (sedentary control), OBESE-ET (treadmill 25 m/min, 1 h, 5 d/week), OBESE-CH (0.5% Chlorella powder in normal diet), and OBESE-ET+CH (combination of ET and CH intake) groups. The carotid–femoral pulse wave velocity (cfPWV), an index of arterial stiffness, was significantly lesser in the OBESE-ET, OBESE-CH, and OBESE-ET+CH groups than in the OBESE-SED group, and in the OBESE-ET+CH group significantly further enhanced these effects compared with the OBESE-ET and OBESE-CH groups. Additionally, arterial nitrate/nitrite (NOx) levels were significantly greater in the OBESE-ET, OBESE-CH, and OBESE-ET+CH groups than in the OBESE-SED group, and the OBESE-ET+CH group compared with the OBESE-ET and OBESE-CH groups. Furthermore, arterial NOx levels were positively correlated with arterial endothelial NO synthase phosphorylation levels (r = 0.489, p < 0.05) and negatively correlated with cfPWV (r = −0.568, p < 0.05). In conclusion, a combination of ET and CH intake may reduce arterial stiffness via an enhancement of the arterial NO signaling pathway in obese rats. [ABSTRACT FROM AUTHOR]

Chlorella species of microalgae are utilized in the crop and food industries. The aim of this research was to investigate the metabolite profiles of Chlorella fusca for the first time and evaluate its biological properties. The two ion modes of UPLC-Q-TOF-MS/MS were used to identify a total of 62 components in the methanol extract of C. fusca, with 26 in the negative and 36 in the positive ion mode, including 10 identical ingredients. Fatty acids (negative mode) and combinations of chlorophyll and fatty acids (positive mode) were the most prevalent chemical structures, constituting over 80 and 70% of the total metabolites, respectively, followed by chlorophyll, polar lipids, carotenoids, and fatty alcohols. Moreover, this extract exhibited potent antioxidant and anti-aging benefits in decreasing order of potency at a concentration of 200 |g mL-1: tyrosinase inhibition (100%), ABTS radical scavenging (90%), elastase inhibition (88%), and DPPH radical scavenging (34%). Notably, this extract protected the mobility of DNA fragments up to 5 μg mL-1 (26%), with potential effects (> 60% at 200 μg mL-1). These findings suggest that C. fusca may be a promising candidate for applications related to its biological functions, owing to the high accumulation of fatty acids and chlorophyll derivatives. [ABSTRACT FROM AUTHOR]

Protists, including ciliates retain crystals in their cytoplasm. However, their functions and properties remain unclear. To comparatively analyze the crystals of Paramecium bursaria, a ciliate, associated with and without the endosymbiotic Chlorella variabilis, we investigated the isolated crystals using a light microscope and analyzed their length and solubility. A negligible number of crystals was found in P. bursaria cells harboring symbiotic algae. The average crystal length in alga-free and algae-reduced cells was about 6.8 μm and 14.4 μm, respectively. The crystals of alga-free cells were spherical, whereas those of algae-reduced cells were angular in shape. The crystals of alga-free cells immediately dissolved in acids and bases, but not in water or organic solvents, and were stable at – 20 °C for more than 3 weeks. This study, for the first time, reveals that the characteristics of crystals present in the cytoplasm of P. bursaria vary greatly depending on the amount of symbiotic algae. [ABSTRACT FROM AUTHOR]

Abstract Microalgae are emerging as functional feed ingredients in aquaculture due to their immune-stimulating and stress-modulating properties. We investigated the potential of the microalgae Chlorella vulgaris as a feed supplement to improve the health and modulate microbiota and stress responses of Atlantic salmon. Triplicate groups of Atlantic salmon (~ 126 g) were reared in a recirculating aquaculture system (RAS) at 15 °C and received diets supplemented with 2% (CV2) or 14% (CV14) spray-dried C. vulgaris daily, 14% once weekly (CV14w), or a control diet (CD) for 8 weeks. Subsequently, all groups were exposed to an acute one-hour peracetic acid (CH3CO3H; PAA) treatment, a commonly used disinfectant in RAS. While CV14 increased feed conversion (FCR) significantly, feeding the diets CV2 and CV14w improved protein retention efficiency. CV14 significantly modulated beta-diversity in the intestinal digesta and mucosa, but this effect was already visible in fish fed CV2. Feeding CV14 and, to a lesser degree, CV2 increased the relative abundances of Paenarthrobacter and Trichococcus in the digesta and mucosa, which are able to metabolize complex carbohydrates. However, the same diets reduced the abundance of the lactic acid bacteria Lactobacillus and Weissella in the digesta and Floricoccus in the mucosa. Peracetic acid exposure induced systemic stress (increase in plasma glucose and cortisol) and a local immune response in the gill, with the most prominent upregulation of several immune- and stress-regulated genes (clra, cebpb, marco, tnfrsf14, ikba, c1ql2, drtp1) 18 h after exposure in fish fed the control diet. Fish receiving CV14 once a week showed a reduced transcriptional response to PAA exposure. Catalase protein abundance in the liver increased following exposure to PAA, while superoxide dismutase abundance in the gill and liver was increased in response to C. vulgaris inclusion before stress. Overall, the results highlight that a high (14%) inclusion rate of C. vulgaris in feed for Atlantic salmon impairs feed conversion and shifts the intestinal microbiota composition in digesta and mucosa. Weekly feeding of C. vulgaris proves a viable approach in improving protein retention and improving transcriptional resilience towards oxidative stress in increasingly intensive production systems. Thereby this study may motivate future studies on optimizing temporal feeding schedules for health-promoting aquafeeds.

• Chlorella proteinosa was cultivated in an MPBR for secondary effluents treatment. • Highest TN removal rate of 23.8 mg/L/day was achieved at a lowest HRT of 8 hr. • Highest microalgae biomass productivity reached 20.2 mg/L/day at the HRT of 8 hr. • Bacterial nitrogen respiration was reduced by 95.5 % from an HRT of 24 hr to 8 hr. Further treatment of secondary effluents before their discharge into the receiving water bodies could alleviate water eutrophication. In this study, the Chlorella proteinosa was cultured in a membrane photobioreactor to further remove nitrogen from the secondary effluents. The effect of hydraulic retention time (HRT) on microalgae biomass yields and nutrient removal was studied. The results showed that soluble algal products concentration reduced in the suspension at low HRT, thereby alleviating microalgal growth inhibition. In addition, the lower HRT reduced the nitrogen limitation for Chlorella proteinosa 's growth through the phase-out of nitrogen-related functional bacteria. As a result, the productivity for Chlorella proteinosa increased from 6.12 mg/L/day at an HRT of 24 hr to 20.18 mg/L/day at an HRT of 8 hr. The highest removal rates of 19.7 mg/L/day, 23.8 mg/L/day, and 105.4 mg/L/day were achieved at an HRT of 8 hr for total nitrogen (TN), ammonia, and chemical oxygen demand (COD), respectively. However, in terms of removal rate, TN and COD were the largest when HRT is 24 hr, which were 74.5% and 82.6% respectively. The maximum removal rate of ammonia nitrogen was 99.2% when HRT was 8 hr. [Display omitted] [ABSTRACT FROM AUTHOR]

Chlorella vulgaris and Scenedesmus sp. are commonly used in wastewater treatment due to their fast growth rates and ability to tolerate a range of environmental conditions. This study explored the cultivation of Chlorella vulgaris and Scenedesmus sp. using wastewater from the food industry, particularly from Italian basil pesto production tanks. The experiment involved different carbon dioxide concentrations and light conditions with a dilution rate of basil pesto wastewater at 1:2. Both microalgae strains were able to grow on pesto wastewater, and biomass characterization highlighted the influence of CO2 supply and light irradiation. The highest lipid storage was 79.3 ± 11.4 mg gdry biomass−1 and 75.5 ± 13.3 mg gdry biomass−1 for C. vulgaris and S. obliquus under red light (5% CO2 supply) and white light (0.04% CO2 supply), respectively. Protein storage was detected at 20.3 ± 1.0% and 24.8 ± 1.3% in C. vulgaris and S. obliquus biomasses under white light with a 5% CO2 and 0.04% CO2 supply, respectively. The removal of P, N, chemical oxygen demand, and biological oxygen demand resulted in 80–100%, 75–100%, 26–35%, and 0–20%, respectively.

To investigate the difference of the components and antioxidant activity between the Se-enriched and the common chlorella extract, as well as the correlation between the components and antioxidant activity. This study determined the content of total nitrogen, total sugar, polyphenols, flavonoids, saponins, total selenium, polysaccharide and polysaccharide selenium in selenium-enriched and common chlorella extract and their ability to reduce Fe3+, scavenge DPPH·, ABTS+·, · OH and O2-·, as well as the correlation between the content and antioxidant capacity. The results showed that compared with common chlorella extract, selenium-enriched chlorella extract contained more content of total sugar, polyphenol, flavonoid, total selenium, polysaccharide and polysaccharide selenium (P<0.05), but less total nitrogen and saponins (P<0.05). The Se-enriched chlorella extract had higher activity in reducing Fe3+ and scavenging DPPH· and ABTS+·, but lower activity in scavenging ·OH and O2-· than that of common chlorella extract. Correlation analysis showed that higher content of nitrogen, total sugar, polyphenols, flavonoids, saponins, total selenium, polysaccharide and polysaccharide selenium could strengthen the antioxidant activity (P<0.05). The ·OH scavenging capacity was negatively correlated with total selenium and polysaccharide selenium (P<0.05). In general, Se-enriched chlorella extract had more physiological active substances (except total nitrogen and saponins) and stronger antioxidant activity, which would provide the potential application for Se-enriched chlorella extract in health food products. [ABSTRACT FROM AUTHOR]

This study optimized the extraction process of Chlorella protein using response surface methodology and characterized its secondary structure. With the protein solubility rate of Chlorella as the indicator, the effects of ultrasonic power, ultrasonic time, NaOH mass fraction, and water bath time on the extraction rate were investigated. Based on the Plackett-Burman design, a four-factor three-level response surface analysis was conducted to determine the extraction process of Chlorella protein. The results showed that the optimal extraction conditions for Chlorella protein were ultrasonic power of 460.08 W, ultrasonic time of 16.05 min, NaOH mass fraction of 14.03%, and water bath time of 37.18 min, with a solubility rate of 87.64%. The extracted Chlorella protein was purified using isoelectric focusing under optimal conditions and then subjected to FTIR analysis, microscopic structure analysis, and amino acid analysis. The results indicated that the secondary structure of Chlorella protein mainly consisted of β-sheet, accounting for 30.00% of the total content. The microscopic structure revealed a smooth surface with pore structures, and it contained five essential amino acids, accounting for 42.71% of the total content. In conclusion, the ultrasonic-assisted alkaline method demonstrates significantly improved protein wall-breaking efficiency and high protein extraction rate for Chlorella, with simple operation and low cost. It has promising prospects for industrial applications and provides relevant references for the food application of Chlorella protein. [ABSTRACT FROM AUTHOR]

Simple Summary: This study examines the use of dairy wastewater to cultivate three types of microalgae: Spirulina platensis, Micractinium, and Chlorella. The research found that these algae can effectively remove nutrients like nitrogen and phosphorus from industrial wastewater. Spirulina sp. and a mixed culture of all three algae performed best, significantly reducing nitrogen levels, while Chlorella sp. also removed a substantial amount of phosphorus. Additionally, microalgae treatment greatly reduced pathogens. These results suggest that microalgae could be a promising method for treating dairy wastewater and improving water quality. This study explores the novel use of mixed cultures of microalgae—Spirulina platensis, Micractinium, and Chlorella—for nutrient removal from dairy wastewater (DW). Microalgae were isolated from a local wastewater treatment plant and cultivated under various light conditions. The results showed significant biomass production, with mixed cultures achieving the highest biomass (2.51 g/L), followed by Spirulina (1.98 g/L) and Chlorella (1.92 g/L). Supplementing DW (75%) with BG medium (25%) significantly enhanced biomass and pH levels, improving pathogenic bacteria removal. Spirulina and mixed cultures exhibited high nitrogen removal efficiencies of 92.56% and 93.34%, respectively, while Chlorella achieved 86.85% nitrogen and 83.45% phosphorus removal. Although growth rates were lower under phosphorus-limited conditions, the microalgae adapted well to real DW, which is essential for effective algal harvesting. Phosphorus removal efficiencies ranged from 69.56% to 86.67%, with mixed cultures achieving the highest removal. Microbial and coliform removal efficiencies reached 97.81%, with elevated pH levels contributing to significant reductions in fecal E. coli and coliform levels. These findings suggest that integrating microalgae cultivation into DW treatment systems can significantly enhance nutrient and pathogen removal, providing a sustainable solution for wastewater management. [ABSTRACT FROM AUTHOR]

The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. The objective of this study was to evaluate the interaction of dietary carbohydrate profile and soybean meal (SBM) replacement with either Chlorella pyrenoidosa (CHL) or Spirulina platensis (SPI) on in vitro fermentation. This experiment was conducted as a randomized complete block design, with fermentation run (3 runs) considered as blocks. The treatments were arranged in a 2 × 5 factorial design, where the first factor was the carbohydrate profile, which was composed of diets containing 42.5% neutral detergent fiber (NDF) and 26.8% starch (HF-LS) or 26.8% NDF and 40.6% starch (LF-HS), and the second factor was the protein source, in which a control diet (100% SBM), partial replacement of SBM with CHL (1/2CHL) or SPI (1/2SPI), or total replacement of SBM with CHL or SPI were used. All experimental diets were formulated to have 17% crude protein. The ruminal fluid was collected from 2 lactating Holstein cows, buffered with Van Soest medium at a ratio of 1:2 and added to serum bottles containing 0.50 g of the experimental diets. Bottles were incubated at 39°C for 24 and 48 h in triplicate; headspace pressure was measured, along with gas collection for methane (CH 4) quantification at 0, 2, 4, 8, 16, 24, 36, and 48 h after incubation. The final medium was used to measure pH, ammonia, and VFA. After incubation, feed bags were recovered and used for estimation of dry matter (DM), NDF, and organic matter (OM) degradability. Statistical analysis was carried out using the MIXED procedure of SAS, with carbohydrate profile, protein source, assay, and their interactions as fixed effects, with run and bottle as random effects. Orthogonal contrasts were used to compare carbohydrate profile, algae species, carbohydrate profile × algae interaction, and linear and quadratic effects of SBM replacement with CHL or SPI. There was no interaction effect between carbohydrate profile and algae source. The LF-HS improved gas production, degradability of nutrients, and VFA, mainly increasing the production of butyrate and propionate. When compared with CHL, SPI had a greater degradability of nutrients and branched VFA, along with reduction in total gas production and tended to reduce total CH 4 yield. The replacement of SBM with algae linearly reduced the degradability of nutrients, along with a linear reduction in gas production. When replacement of SBM with only SPI was evaluated, SPI slightly reduced the degradability of nutrients; however, it promoted a linear reduction in CH 4 yield, as well as reduction in CH 4 yield by unit of degraded DM, NDF, and OM. In summary, there was no interaction of carbohydrate profile and protein source, which means that SBM replacement had a similar effect, regardless of dietary carbohydrate profile. Spirulina may be a more suitable algae source than Chlorella due to the potential to reduce CH 4. [ABSTRACT FROM AUTHOR]

This study aims to reveal how height/diameter ratio of column photobioreactors affect the growth and lipid content of microalgae. For this purpose, Chlorella variabilis cells were grown in aerated column photobioreactors with height/diameter ratio of 1, 2, and 3 in defined (BG11) culture medium. Results obtained showed that maximum microalgae biomass concentration, cell productivity, cell doubling time, and lipid productivity were found to increase as the height/diameter of photobioreactor increased. After 15 days of cultivation, the highest cell productivity (0.139 gdw/L.day), cell lipid content (21.1%) and lipid productivity (29.33 mg/L.day) were obtained in the photobioreactor with the highest height/diameter ratio (3), whereas the highest specific growth rate (0.045 h-1) was obtained in the photobioreactor with the smallest height/diameter ratio (1). These findings contribute to the knowledge on photobioreactor design and pave way for more efficient use of column type photobioreactors in producing microalgae. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the sulfur hexafluoride (SF6) tracer technique for estimating methane (CH4) emissions in dual-flow continuous culture systems (DFCCS). In experiment 1 (Exp1), fermenters were filled with water, and known CH4 concentrations (0, 1.35, 2.93, or 4.43 g/d) were injected using permeation tubes with SF6 release rates (3.30 or 9.65 mg/d). Headspace gas was collected using canisters, and the SF6 technique estimated CH4 recovery. Experiment 2 (Exp2) involved a DFCCS fermentation trial with ruminal fluid from three Holstein cows, testing diets with soybean meal or its partial replacement (50%) by Chlorella or Spirulina. Headspace gas was collected at intervals post-feeding. Standard curves for SF6 and CH4 quantification were inadequate for DFCCS samples, with the CH4:SF6 ratio differing from standards, indicating the data needs further SF6 release rate evaluation. In Exp1, a high correlation (r = 0.97) was found between infused and calculated CH4, indicating good repeatability. Low and high SF6 rates performed similarly at low CH4 infusion, but high SF6 overestimated CH4 at high infusion. Exp2 showed CH4 emissions irrespective of SF6 rate and indicated reduced CH4 emissions and increased NDF degradation with algae-containing diets. Further evaluation of the SF6 tracer technique is warranted for DFCCS. [ABSTRACT FROM AUTHOR]

Microalgae can promote antibiotic removal, which has attracted growing attention. However, its synergistic removal performance with bacteria in antibiotic pollutants is still poorly understood. In this study, firstly, we selected two green algae (Dictyosphaerium sp. and Chlorella sp.) and exposed them to Enrofloxacin (ENR) to observe their extracellular polysaccharides (EPS) concentration dynamic and the removal of antibiotics. Secondly, EPS was extracted and added to in situ lake water (no algae) to investigate its combined effect with bacteria. The results indicate that both Dictyosphaerium sp. and Chlorella sp. exhibited high tolerance to ENR stress. When the biomass of microalgae was low, ENR could significantly stimulate algae to produce EPS. The removal rates of Dictyosphaerium sp. and Chlorella sp. were 15.8% and 10.5%, respectively. The addition of EPS can both alter the microbial community structure in the lake water and promote the removal of ENR. The LEfSe analysis showed that there were significant differences in the microbial marker taxa, which promoted the increase of special functional bacteria for decomposing ENR, between the EPS-added group and the control group. The EPS of Dictyosphaerium sp. increased the abundance of Moraxellaceae and Spirosomaceae, while the EPS of Chlorella sp. increased the abundance of Sphingomonadaceae and Microbacteriaceae. Under the synergistic effect, Chlorella sp. achieved a maximum removal rate of 24.2%, while Dictyosphaerium sp. achieved a maximum removal rate of 28.9%. Our study provides new insights into the removal performance and mechanism of antibiotics by freshwater microalgae in water bodies and contribute to the development of more effective water treatment strategies. [ABSTRACT FROM AUTHOR]

Bacteria and microalgae have beneficial impact on plant growth and survival through host functional and adaptive traits via complex mechanisms. Volatile and non-volatile metabolites produced by microorganisms have a continuous effect on plants by providing nutrients and regulating various plant metabolic and signaling pathways. The aim of this study was to assess the plant promoting effect of two Chlorella spp. microalgae under mixotrophic conditions, as well as the effects of plant growth promoting rhizobacteria (PGPR) Bacillus sp. WCC-B36, Azospirillum sp. WCC-ASP12 and Azotobacter sp. WCC-IZA56 on the model plant Arabidopsis thaliana. Growth and quality parameters were followed in three different co-cultivation systems as (i) direct root contact supplemented with density effect, (ii) contact with diffusible compounds and (iii) effects of volatile compounds. Direct effect mediated by rhizobacteria promoted significant shoot and root length growth with well-developed root architecture at low bacterial densities (<105 CFU – colony forming unit mL−1), which became more pronounced over time. At a higher microbial density (>107 CFU mL−1), plant growth was retarded regardless of the bacteria present. This suggests that the microenvironment surrounding the colonies was altered and there was competition for nutrients. Our results indicate that the metabolites, diffusible and volatile organic substances produced by the microalgae enhanced lateral root growth and root hair formation, while inhibited primary root elongation. Volatile and diffusible substances of Chlorella sp. CHL13 and Bacillus sp. WCC-B36 have the most significant effect on seedlings and primary root growth. [ABSTRACT FROM AUTHOR]

Arms race dynamics are a common outcome of host–parasite coevolution. While they can theoretically be maintained indefinitely, realistic arms races are expected to be finite. Once an arms race has ended, for example due to the evolution of a generalist-resistant host, the system may transition into coevolutionary dynamics that favour long-term diversity. In microbial experiments, host–parasite arms races often transition into a stable coexistence of generalist-resistant hosts, (semi-)susceptible hosts, and parasites. While long-term host diversity is implicit in these cases, parasite diversity is usually overlooked. In this study, we examined parasite diversity after the end of an experimental arms race between a unicellular alga (Chlorella variabilis) and its lytic virus (PBCV-1). First, we isolated virus genotypes from multiple time points from two replicate microcosms. A time-shift experiment confirmed that the virus isolates had escalating host ranges, i.e., that arms races had occurred. We then examined the phenotypic and genetic diversity of virus isolates from the post-arms race phase. Post-arms race virus isolates had diverse host ranges, survival probabilities, and growth rates; they also clustered into distinct genetic groups. Importantly, host range diversity was maintained throughout the post-arms race phase, and the frequency of host range phenotypes fluctuated over time. We hypothesize that this dynamic polymorphism was maintained by a combination of fluctuating selection and demographic stochasticity. Together with previous work in prokaryotic systems, our results link experimental observations of arms races to natural observations of long-term host and parasite diversity. Graphical Abstract [ABSTRACT FROM AUTHOR]

The present study aimed to detect the production of Ergosterol in Chlorella sorokinana and the effect of sodium chloride (NaCl), and the difference of growth phases on the production of the compound and photosynthetic pigments. The results showed that there is a positive effect on increasing the production of the Ergosterol compound. Its maximum value was 48.591 mg. L-1 at the concentration of 300 ppm. Concerning the difference in growth phases, the second growth phase was the best in obtaining the maximum value of Ergosterol, which was 44. 941 mg. L-1. Also, the results of the interaction between the concentrations of NaCl and the difference in the growth phases indicated that the highest value was 50.493 mg. L-1 at the concentration of 300 ppm at the second growth phase. In contrast, there was a negative effect of NaCl on photosynthetic pigments; the highest values of chlorophyll a and b and total chlorophyll were 0.04, 0.07, and 0.13, respectively, at the control treatment, whereas these values gradually decreased with the increase of NaCl concentration to reach the lowest values; these were 0.01, 0.04 and 0.06 mg. L-1 respectively at the concentration of 300 ppm. The results of the different dates of cell harvesting showed that the highest values for obtaining an increase in the concentration of chlorophyll a and b pigments and total chlorophyll were at phases 1; they were 0.06, 0.09, and 0.17 mg. L-1 respectively. Accordingly, we concluded that the salt stress from NaCl had a positive effect on increasing the concentration of Ergosterol, which is one of the antioxidant steroidal compounds. On the other hand, it had a negative effect on the photosynthetic pigments. [ABSTRACT FROM AUTHOR]

The present study reports a new representative of Chlorella‐clade that was newly isolated from the Lake Vos'merka (Samara region, Russian Federation). 18S–ITS1–5.8S–ITS2 sequence analyses indicated that the studied strain ACSSI 368 and related Chlorella chlorelloides, Chlorella pulchelloides, formed an separate cluster in the Chlorella‐clade, unrelated to the holotype of the genus Chlorella – Chlorella vulgaris. The independent place of the genus was also confirmed by genetic distances. The individual species status of the studied strain ACSSI 368, compared with the sister C. chlorelloides, was confirmed by morphological differences (cell number per colony, type of chloroplast, number of autospores), genetic distances of the interspecific level by 18S–ITS1–5.8S–ITS2 fragment, alone by internal transcribed spacer 1 (ITS1) and internal transcribed spacer 2 (ITS2) sequences, one complementary base change in ITS1, and the results of species delimitation using five methods. A description of studied strain ACSSI 368 was provided as an authentic strain of the type species Aliichlorella ignota. Currently, the new genus Aliichlorella also includes Aliichlorella chlorelloides comb. nov. and Aliichlorella pulchelloides comb. nov. In general, six different delimitation algorithms were used in the present study. The ASAP (i.e. assemble species by automatic partitioning) and LocMin (i.e. 'local minimum' function) algorithms showed synchronous results, but their accuracy with respect to closely related species was somewhat lower. The mlPTP algorithm simultaneously aimed to combine closely related species in one and at the same time divide slightly distinguishing strains within a species into several molecular operational taxonomic units. The bPTP algorithm separated excessively Chlorella‐clade representatives into individual species. The generalized mixed Yule coalescent (GMYC) algorithm results were consistent the most with the modern understanding of the Chlorella‐clade taxonomy. However, the same method is one of the most time‐consuming because, for its implementation, it is necessary to carry out long preparatory work. The KoT results were less accurate than the GMYC results, although this is less time‐consuming because it does not require the preliminary construction of ultrametric trees. [ABSTRACT FROM AUTHOR]

Summary: The production of alkaliphilic microalgae can contribute to address the challenging cost of using pure carbon dioxide in large reactors. At high pH values, carbon dioxide is rapidly scavenged and the supply rates of dissolved inorganic carbon from the atmosphere to alkaline media are high. The present study aimed to identify microalgal strains that can cope with high alkalinity and aeration rates. Eight strains were studied and the microalgae Chlorella vulgaris, Scenedesmus almeriensis and Nannochloropsis gaditana were the only ones that were able to grow under these conditions. Their biomass productivities using laboratory‐scale bubble columns with no pH control and high aeration flow were 0.20 ± 0.03, 0.24 ± 0.03 and 0.08 ± 0.01 g·L−1·day−1, respectively. The production of the two former was scaled up to pilot‐scale bubble columns. Overall, the amount of atmospheric carbon dioxide that was transformed into biomass was in the range of 10%–30%, depending on the strain used and the photobioreactor setup. The biomass was rich in proteins and β‐carotene, both valuable products, highlighting the potential production of food ingredients while capturing carbon dioxide from the atmosphere. [ABSTRACT FROM AUTHOR]

Rapid growth of antimicrobial resistance is a major threat to human and animal health, and development of new drugs with effective microbicidal properties are in demand to the scientific communities. Cyanobacteria and medicinal plants inherit antimicrobial, antioxidant, anti-cancerous and anti-inflammatory properties. In the current research, we investigated antibacterial potential of crude ethanolic extracts from marine microalgae (Chlorella sp. and Spirulina sp.) and medicinal plants (Aloe vera and Clinacanthus nutans) against pathogenic bacteria isolated from chicken, dog, fish, and shellfish. Bacteria including Salmonella sp., Aeromonas sp. and E. coli, Vibrio sp. Streptococcus sp. and Staphylococcus sp., were isolated through colony morphology, Gram staining and VITEK-2 tests. Antibacterial activity was determined by disc diffusion assay. Spirulina sp. showed the highest inhibition zone of 19.3±0.58 mm against Vibrio sp. compared to other treatments, whereas Chlorella sp. exhibited maximum inhibition zone of 11.41±0.65 mm against Staphylococcus sp., C. nutans had antibacterial activity against Staphylococcus sp. and E. coli with the maximum zone of inhibition (14.21±1.08 and 15.10±0.21 mm), whereas Aloe vera against E. coli and Vibrio sp. with significant inhibition zone of 14.04±0.90 and 15.36±1.11mm, respectively. Minimum inhibitory concentration (MIC) of Chlorella sp. was found to be 20 mg/mL against all the test bacteria. Spirulina sp., Aloe vera, and C. nutans had MIC values ranging from 20-40 mg/mL. These findings highlight the antibacterial potential of native microalgae and medicinal plants against virulent bacteria that poses significant threats in poultry, canine and aquaculture. [ABSTRACT FROM AUTHOR]

During the previous few decades, the pursuit has experienced an increase for novel marine-derived molecules with potential use in the pharmaceutical, human or animal nutrition, cosmetics, and bioenergy industries. The current study aimed at obtaining the optimum growth rate of some microalgal isolates and finding their antibacterial activity. The microalgae were purified in BG11 medium and the biomass extracted using ethanol, acetone, diethyl ether and methanol was then examined for antimicrobial activity by disc diffusion and minimum inhibitory concentration methods.The optimum growth rate obtained at pH 8, temperature 26-28 °C, and 2000 lux for all algal isolates. All microalgae extracts showed antimicrobial activity against tested bacteria with different solvents. The higher antibacterial activity obtained with ethanol extracts while water extract showed low antibacterial activity. Chlorella sp. and Spyrogyra sp. showed higher antibacterial rather than other isolates. Overall, these results imply that microalgae extracts, particularly those from Spirogyra sp. and Chlorella sp., may be sources of antibacterial chemicals. To identify and describe the precise bioactive substances in charge of the reported inhibitory effects, additional study is required. Further research into the mechanisms of action, safety, and possible uses of these microalgae extracts in bacterial infection management would be advantageous. [ABSTRACT FROM AUTHOR]

This study investigates the effectiveness of Chlorella vulgaris in treating copper, cadmium, and zinc in aqueous solutions; the aim of this study was to examine the effects of various factors on the adsorption capacity of Chlorella in water. This study explored the intra- and extracellular adsorption and accumulation patterns of copper (Cu(II)), cadmium (Cd(II)), and zinc (Zn(II)), revealing their molecular response mechanisms under the most suitable conditions. The adsorption capacity of Chlorella to Cu(II), Cd(II), and Zn(II) in water was 93.63%, 73.45%, and 85.41%, respectively. The adsorption mechanism for heavy metals is governed by both intracellular and extracellular diffusion, with intracellular absorption serving as a supplement and external uptake predominating. XRD, XPS, FTIR, SEM-EDX, and TEM-EDX analyses showed that there would be the formation of precipitates such as Cu2S, CuS2, CdS, and ZnSO4. The adsorption of Cu(II) involves its simultaneous reduction to Cu(I). Moreover, specific functional groups present on the cellular surface, such as amino, carboxyl, aldehyde, and ether groups, interact with heavy metal ions. In view of its efficient heavy metal adsorption capacity and biosafety, this study recommends Chlorella as a potential biosorbent for the bioremediation and environmental treatment of heavy metal contaminated water in the future. [ABSTRACT FROM AUTHOR]

A complex evaluation of antimicrobial activities of microalgae, including those relevant to wastewater treatment (WWT), in light of the integrated biorefinery concept, is performed. An example of this concept is linking a commercial microalgal system to plants, factories, or farms that emit polluted wastewater (WW). The microalgae would not only metabolize the pollutants—such as nitrogen (N) and phosphorus (P)—from the WW, thus fueling their biomass, but they would exert an antibacterial effect against the pathogenic bacteria there. The biomass then could be harvested and used for biofertilizers, biofuels, and bioplastics and might possibly be utilized as animal feed, antimicrobial and other pharmaceutical agents. A large amount of the research on the antimicrobial activity and WWT potential focuses on the families Chlorellaceae and Scenedesmaceae, which are also some of the most commercially used strains of microalgae. For that reason, they are the species chosen for the current review. Furthermore, the increasing antimicrobial resistance necessitates the search for antibiotic alternatives, and the antibacterial and antifungal activity of Chlorellaceae and Scenedesmaceae is very promising. Microalgae are rich in antibacterial compounds like polyunsaturated fatty acids (PUFAs), polysaccharides, carotenoids, proteins, etc., and for that reason, their extracts possess antimicrobial effects. The in vitro antimicrobial activity of Chlorellaceae and Scenedesmaceae families has varied in a broad range from low to strong activity or no effect. Several strains have fulfilled the criteria for outstanding and high activity, especially C. vulgaris and other Chlorellaceae spp., with an effect equal to or better than the control antibiotics. There were several strains with minimum inhibitory concentrations (MIC) below 80 µg/mL and even 10 and 1.5 µg/mL; some species also had inhibition zones (IZ) over 30 mm, even as high as 48 mm. In vivo results are also promising but scarce, and all this warrants further in vivo and in situ studies—from animal models to clinical and environmental trials. Altogether, important data in the light of the circle economy, the urgent necessity to decrease CO2 emissions to fight climate change, and to curb the harmful influence of future pandemics are presented. This review paves the way for further utilizing the total potential of a microalgal system. [ABSTRACT FROM AUTHOR]

The effects of microalgae Chlorella pyrenoidosa on the hybrid groupers' (Epinephelus lanceolatus♂ × E. fuscoguttatus♀) growth, gut microbiome, and transcriptome were examined in this study. Feeding trials with a duration of 15 days (15d) and 60 days (60d) were conducted on three experimental groups (n = 3) as follows: (T1) grouper fed with basal diet and reared in filtered seawater (control treatment); (T2) grouper fed with basal diet and reared in C. pyrenoidosa monoculture water (CMW); and (T3) grouper fed with basal diet partially replaced with 15% of dried C. pyrenoidosa (CRM) and reared in filtered seawater. The findings revealed that groupers reared 15d in T2 treatment (T2-15d) had a higher fat content, with an apparent shift of microbial composition and functional pathways in the gut. Groupers reared 60d in T2 treatment (T2-60d) displayed an increased NADH dehydrogenase and cytochrome c oxidases gene expression, indicating more robust oxidative phosphorylation activity and ATP production crucial for metabolic homeostasis. The reduction in the total amino acid content was also detected in groupers raised in T2-60d. Gastritis, enteritis, and lipid malabsorption syndrome were observed in groupers raised 60d in T3 treatment (T3-60d), with the condition likely due to a higher intake of omega-6 to omega-3 fatty acids ratio in groupers raised 15 days in T3 (T3-15d) and T3-60d. All signs of intestinal inflammation may arise from the inclusion of dried C. pyrenoidosa. Overall, outcomes from this study revealed that introducing live C. pyrenoidosa to the culture water is advantageous for digestion and enhances the energy metabolism of juvenile groupers. [ABSTRACT FROM AUTHOR]

Chlorella vulgaris and Scenedesmus sp. are commonly used in wastewater treatment due to their fast growth rates and ability to tolerate a range of environmental conditions. This study explored the cultivation of Chlorella vulgaris and Scenedesmus sp. using wastewater from the food industry, particularly from Italian basil pesto production tanks. The experiment involved different carbon dioxide concentrations and light conditions with a dilution rate of basil pesto wastewater at 1:2. Both microalgae strains were able to grow on pesto wastewater, and biomass characterization highlighted the influence of CO2 supply and light irradiation. The highest lipid storage was 79.3 ± 11.4 mg gdry biomass−1 and 75.5 ± 13.3 mg gdry biomass−1 for C. vulgaris and S. obliquus under red light (5% CO2 supply) and white light (0.04% CO2 supply), respectively. Protein storage was detected at 20.3 ± 1.0% and 24.8 ± 1.3% in C. vulgaris and S. obliquus biomasses under white light with a 5% CO2 and 0.04% CO2 supply, respectively. The removal of P, N, chemical oxygen demand, and biological oxygen demand resulted in 80–100%, 75–100%, 26–35%, and 0–20%, respectively. [ABSTRACT FROM AUTHOR]

Primary excitation energy transfer and charge separation in photosystem I (PSI) from the extremophile desert green alga Chlorella ohadii grown in low light were studied using broadband femtosecond pump-probe spectroscopy in the spectral range from 400 to 850 nm and in the time range from 50 fs to 500 ps. Photochemical reactions were induced by the excitation into the blue and red edges of the chlorophyll Qy absorption band and compared with similar processes in PSI from the cyanobacterium Synechocystis sp. PCC 6803. When PSI from C. ohadii was excited at 660 nm, the processes of energy redistribution in the light-harvesting antenna complex were observed within a time interval of up to 25 ps, while formation of the stable radical ion pair P700+A1− was kinetically heterogeneous with characteristic times of 25 and 120 ps. When PSI was excited into the red edge of the Qy band at 715 nm, primary charge separation reactions occurred within the time range of 7 ps in half of the complexes. In the remaining complexes, formation of the radical ion pair P700+A1− was limited by the energy transfer and occurred with a characteristic time of 70 ps. Similar photochemical reactions in PSI from Synechocystis 6803 were significantly faster: upon excitation at 680 nm, formation of the primary radical ion pairs occurred with a time of 3 ps in ~30% complexes. Excitation at 720 nm resulted in kinetically unresolvable ultrafast primary charge separation in 50% complexes, and subsequent formation of P700+A1− was observed within 25 ps. The photodynamics of PSI from C. ohadii was noticeably similar to the excitation energy transfer and charge separation in PSI from the microalga Chlamydomonas reinhardtii; however, the dynamics of energy transfer in C. ohadii PSI also included slower components. [ABSTRACT FROM AUTHOR]

In this study, microalgae proteins (Spirulina and Chlorella) were extracted, characterized, and investigated for their potential techno-functionalities. The proteins from the microalgae biomass were extracted by alkaline solubilization followed by iso-electric precipitation. Subsequently, their physicochemical characteristics (microstructure, thermal stability, secondary structure, and crystallinity) and functional properties (protein solubility, water and oil holding capacities, as well as emulsifying and foaming properties) were investigated. Spirulina biomass resulted in a high extraction yield (37%), giving a protein isolate containing 90% of proteins. Both Spirulina and Chlorella protein extracts displayed high thermal stability. FTIR analysis revealed a clear difference in the secondary structure of the protein extracts. A slight difference in microstructure was noted between the two proteins, but both had small particle sizes and uniform dispersity. Spirulina proteins were more crystalline (53%) than the Chlorella proteins (36%). Spirulina showed better functional properties (protein solubility, emulsifying, and foaming properties) compared to Chlorella. We observed that the Spirulina protein had more water-holding capacity than the Chlorella protein, while the latter also showed appreciable oil-holding capacity. These findings suggest that the microalgal proteins could be useful in the food industry. [ABSTRACT FROM AUTHOR]

One of the organic fertilizers that has the potential to cultivate Chlorella sp. is the cow's rumen. To increase the nutrient content in the cow's rumen, the cow's rumen must be made into bokashi and enriched with chicken manure. This study aimed to determine the use of cow's rumen bokashi enriched with chicken manure at different doses on Chlorella sp cell density. The research design used was a Completely Randomized Design (CRD) with 5 treatments and 3 replications, namely P0 (2 g/L cow's rumen bokashi), P1 = 2 g/L cow's rumen bokashi enriched with 2.5 g/L chicken manure, P2 = 2 g/L cow's rumen bokashi enriched with 3.0 g/L chicken manure, P3 = 2 g/L cow's rumen bokashi enriched with 3.5 g/L chicken manure, and P4 = 2 g/L cow's rumen bokashi enriched with 4.0 g/L chicken manure. The results showed that the highest cell density of Chlorella sp. occurred in treatment P3 (i.e. 456.1 ± 15.1 × 104 cells/mL) and the highest specific growth rate occurred in treatment P0 (i.e. 0.20 ± 0.0/day). Nutrient levels in the culture medium are optimal for Chlorella sp., with nitrate ranging from 0.1375 to 0.2833 mg/L and phosphate ranging from 2.4889 to 2.8650 mg/L. From the results of this study, it can be concluded that the use of cow's rumen bokashi enriched with chicken manure had a very significant effect on cell density and specific growth rate of Chlorella sp. (P<0.01). [ABSTRACT FROM AUTHOR]

Recombinant protein expression is a fundamental aspect of both synthetic biology and biotechnology as well as a field unto itself. Microalgae, with their eukaryotic cellular machinery, high lipid content, cost-effective cultivation conditions, safety profile for human consumption, and environmentally friendly attributes, are a promising system for protein expression or metabolic engineering for sustainable chemical production. Amongst the incredible diversity of microalgae species, Chlorella spp. are heavily studied due to their high growth efficiency, potential for low-cost cultivation, and well-characterized scale-up process for large-scale cultivation. This review aims to comprehensively examine the ongoing advancements in the bioengineering of Chlorella spp. for recombinant protein production and its biotechnological applications. This includes genetic elements such as promoters, terminators, reporters and markers, enhancers, and tags successfully used in Chlorella spp. [ABSTRACT FROM AUTHOR]

With the wide application of nanomaterials, the concentration of nanomaterials in natural water continues to increase, which poses a severe threat to the water environment. However, the influence of organic matter and nanomaterials rich in natural water on the toxic effect of algae growth is still unclear. In this study, the effects of humic acid (HA) and nano-cerium oxide (nCeO2) on the physiology and transcriptome of Chlorella sp. were analyzed, and the mechanism of the toxic effect of HA on Chlorella sp. under nCeO2 stress was revealed. Under 20–200 mg/L nCeO2 stress, the growth of Chlorella cells was inhibited and the highest inhibition rate reached 52% within 200 mg/L nCeO2. The Fv/Fm and ETRmax values of Chlorella sp. decreased from 0.490 and 24.45 (20 mg/L nCeO2) to 0.488 and 23.4 (100 mg/L nCeO2), respectively. Under the stimulation of nCeO2, the level of reactive oxygen species in algal cells was increased, accompanied by lipid peroxidation and membrane damage. However, the addition of HA at concentrations of 5–10 mg/L effectively alleviated the toxic effect of nCeO2 on Chlorella sp. Transcriptome analysis showed that 10 mg/L HA could alleviate the cellular stress at 100 mg/L nCeO2 on Chlorella sp. by regulating genes related to photosynthesis and metabolism pathways. Moreover, the downregulation of genes (e.g., Lhca1, Lhcb1, AOC3, and AOC2) indicated that HA reduced the level of oxidative stress in Chlorella sp. These findings offer novel insights of evaluating the ecotoxicity nCeO2 and HA in natural water environment and their impact on Chlorella sp. [ABSTRACT FROM AUTHOR]

To assess the effects of algae supplementation on lipid profiles and blood pressure in adults, we conducted a systematic search in PubMed, Scopus, Web of Science, and Cochrane Library for relevant randomized controlled trials (RCTs). A total of 77 RCTs with 3686 participants were included. Algae supplementation significantly reduced triglycerides (TG) (WMD: −7.99 mg/dL, 95 % CI: −12.71, −3.26), total cholesterol (TC) (WMD: −11.01 mg/dL, 95 % CI: −14.26, −7.76), and low-density lipoprotein (LDL) (WMD: −10.17 mg/dL, 95 % CI: −13.12, −7.22) levels, while increasing high-density lipoprotein (HDL) (WMD: 1.66 mg/dL, 95 % CI: 0.73, 2.59). No significant changes were observed in the LDL/HDL ratio and systolic blood pressure (SBP), but diastolic blood pressure (DBP) significantly decreased (WMD: −1.71 mmHg, 95 % CI: −2.72, −0.71). These findings suggest that algae supplementation can improve cardiovascular health markers, although further research is needed to address the observed variability.

Modern food is evolving in the direction of green, healthy, and convenient products, and developing natural products with health benefits is an important direction for the food industry. Chlorella is rich in nutrients, such as carotene and fatty acids, which provide it with a variety of health benefits, and therefore widely used in the food industry as a health or functional food. This study reviews the research progress and specific applications of Chlorella in health, functional, and other foods, and expounds on the bottlenecks faced in the use of Chlorella in food industry. This review provides a theoretical basis for the research, utilisation, and production of new food materials involving Chlorella.

The main aim of this study was to identify and evaluate the characteristic properties of bitumen modified with algae. Two types of algae, each with distinct gradation and origin, were employed for this investigation. For each type of algae (noted as chlorella and microchlorella), three blends were created with varying algae contents (5%, 10%, and 15% by weight of bitumen), utilizing a 70/100 reference bitumen as the virgin material and a basis for comparison. The properties of the blends were investigated using the Penetration, Softening Point, Elastic Recovery, Force Ductility, Dynamic Viscosity, and Storage Stability tests, both before and after short-term ageing (TFOT). The test results were then used to calculate the Activation Energy (Ea), Viscosity-Temperature Susceptibility (VTS) Index, and Mixing Temperature (Tmixing), along with their respective Pearson Correlation Coefficient (PCC) and R2 and p-values. The main finding of the study was that the addition of a low algae content of 5% caused a change in the classification of the unaged bitumen from 70/100 to 50/70 according to EN 12591 and thus hardened the reference bitumen. Additionally, a strong linear statistical correlation was observed between Ea and the VTS index, suggesting that these values should be considered when characterizing the temperature susceptibility of algae-modified bitumen.

ABSTRACT: The objective of this study was to evaluate the effects of partially replacing soybean meal (SBM) with algal sources on in vitro ruminal fermentation. Using 6 fermenters in a 3 × 3 replicated Latin square with 3 periods of 10 d each, we tested 3 treatments: a control diet (CRT) with SBM at 17.8% of the diet dry matter (DM); and 50% SBM biomass replacement with either Chlorella pyrenoidosa (CHL); or Spirulina platensis (SPI). The basal diet was formulated to meet the requirements of a 680-kg Holstein dairy cow producing 45 kg/d of milk with 3.5% fat and 3% protein. All diets had a similar nutritional composition (16.0% CP; 34.9% NDF; 31.0% starch, DM basis) and fermenters were provided with 106 g DM/d split into 2 portions. After 7 d of adaptation, samples were collected for 3 d of each period for analyses of ruminal fermentation at 0, 1, 2, 4, 6, and 8 h after morning feeding for evaluation of the ruminal fermentation kinetics. For the evaluation of the daily production of total metabolites and for the evaluation of nutrient degradability, samples from the effluent containers were collected daily. Statistical analysis was performed with the MIXED procedure of SAS with treatment, time, and their interactions considered as fixed effects; day, square, and fermenter were considered as random effects. Orthogonal contrasts (CRT vs. algae; and CHL vs. SPI) were used to depict the treatment effect, and significance was declared when P ≤ 0.05. Fermenters that received algae-based diets had a greater propionate molar concentration and molar proportion when compared with the fermenters fed CRT diets. In addition, those algae-fed fermenters had lower branched short-chain fatty acids (BSCFA) and isoacids (IA), which are biomarkers of ruminal protein degradation, along with lower ammonia (NH3-N) concentration and greater nonammonia nitrogen (NAN). When contrasting with fermenters fed SPI-diets, fermenters fed based CHL-diets had a lower molar concentration of BSCFA and IA, along with lower NH3-N concentration and flow, and greater NAN, bacterial nitrogen flow, and efficiency of nitrogen utilization. Those results indicate that CHL protein may be more resistant to ruminal degradation, which would increase efficiency of nitrogen utilization. In summary, partially replacing SBM with algae biomass, especially with CHL, is a promising strategy to improve the efficiency of nitrogen utilization, due to the fact that fermenters fed CHL-based diets resulted in a reduction in BSCFA and IA, which are markers of protein degradation, and it would improve the efficiency of nitrogen utilization. However, further validation using in vivo models are required.

Host–parasite interactions can cause strong demographic fluctuations accompanied by selective sweeps of resistance/infectivity alleles. Both demographic bottlenecks and frequent sweeps are expected to reduce the amount of segregating genetic variation and therefore might constrain adaptation during co‐evolution. Recent studies, however, suggest that the interaction of demographic and selective processes is a key component of co‐evolutionary dynamics and may rather positively affect levels of genetic diversity available for adaptation. Here, we provide direct experimental testing of this hypothesis by disentangling the effects of demography, selection and their interaction in an experimental host–parasite system. We grew 12 populations of a unicellular, asexually reproducing algae (Chlorella variabilis) that experienced either growth followed by constant population sizes (three populations), demographic fluctuations (three populations), selection induced by exposure to a virus (three populations), or demographic fluctuations together with virus‐induced selection (three populations). After 50 days (~50 generations), we conducted whole‐genome sequencing of each algal host population. We observed more genetic diversity in populations that jointly experienced selection and demographic fluctuations than in populations where these processes were experimentally separated. In addition, in those three populations that jointly experienced selection and demographic fluctuations, experimentally measured diversity exceeds expected values of diversity that account for the cultures' population sizes. Our results suggest that eco‐evolutionary feedbacks can positively affect genetic diversity and provide the necessary empirical measures to guide further improvements of theoretical models of adaptation during host–parasite co‐evolution. [ABSTRACT FROM AUTHOR]

Rotavirus is the main cause of acute diarrhea in children up to five years of age. In this regard, probiotics are commonly used to treat or prevent gastroenteritis including viral infections. The anti-rotavirus effect of Bifidobacterium longum and Chlorella sorokiniana, by reducing viral infectivity and improving IFN-type I response, has been previously reported. The present study aimed to study the effect of B. longum and/or C. sorokiniana on modulating the antiviral cellular immune response mediated by IFN-γ, IL-10, SOCS3, STAT1, and STAT2 genes in rotavirus-infected cells. To determine the mRNA relative expression of these genes, HT-29 cells were treated with B. longum and C. sorokiniana alone or in combination, followed by rotavirus infection. In addition, infected cells were treated with B. longum and/or C. sorokiniana. Cellular RNA was purified, used for cDNA synthesis, and amplified by qPCR. Our results demonstrated that the combination of B. longum and C. sorokiniana stimulates the antiviral cellular immune response by upregulating IFN-γ and may block pro-inflammatory cytokines by upregulating IL-10 and SOCS3. The results of our study indicated that B. longum, C. sorokiniana, or their combination improve antiviral cellular immune response and might modulate pro-inflammatory responses. [ABSTRACT FROM AUTHOR]