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Natural flavor and fragrance market size is expected to grow steadily due to the rising consumer demand of natural ingredients. This market request is guided by the general opinion that the production of natural compounds leads to a reduction of pollution, with inherent advantages for the environment and people’s health. The biotransformation reactions have gained high relevance in the production of natural products. In this context, few pieces of research have described the role of microalgae in the oxidation of terpenoids. In this present study, we questioned the role of microalgal based oxidation in the synthesis of high-value flavors and fragrances. This study investigated the role of three different microalgae strains, Chlorella sp. (211.8b and 211.8p) and Chlorococcum sp. (JB3), in the oxidation of different terpenoid substrates: α-ionone, β-ionone, theaspirane and valencene. Unfortunately, the experimental data showed that the microalgal strains used are not responsible for the substrate oxidation. In fact, our experiments demonstrate that the transformation of the four starting compounds is a photochemical reaction that involves the oxygen as oxidant. Even though these findings cast a shadow on the use of these microorganisms for an industrial purpose, they open a new possible strategy to easily obtain nootkatone in a natural way by just using an aqueous medium, oxygen and light.

Establishing a transgenic plant largely relies on a selectable marker gene that can confer antibiotic or herbicide resistance to plant cells. The existence of such selectable marker genes in genetically modified foods has long been criticized. Plant cells generally exhibit too low an activity of phosphomannose isomerase (PMI) to grow with mannose as a sole carbon source. In this study, we characterized PMI from the green microalga Chlorococcum sp. and assessed its feasibility as a selectable marker for plant biotechnology. Chlorococcum sp. PMI (ChlPMI) was shown to be closely related to higher plants but more distant to bacterial counterparts. Overexpression of ChlPMI in tomato induced callus and shoot formation in media containing mannose (6 g/L) and had an average transformation rate of 3.9%. Based on this transformation system, a polycistronic gene cluster containing crtB, HpBHY, CrBKT and SlLCYB (BBBB) was co-expressed in a different tomato cultivar. Six putative transformants were achieved with a transformation rate of 1.4%, which produced significant amounts of astaxanthin due to the expression of the BBBB genes. Taken together, these findings indicate that we have established an additional tool for plant biotechnology that may be suitable for genetically modifying foods safely.

Oleaginous microalgae with high biomass productivity, lipid content, and lipid productivity are desirable for sustainable biofuel production. Rapid and accurate quantification of lipid content facilitates the identification of promising microalgae candidates. In the present study, 23 freshwater microalgae species from river Noyyal were isolated and identified based on their morphological and molecular (18S rRNA) features and recorded as Karunya Algae Culture Collection (KACC). Their biomass and lipid content were characterized and screened using FT-IR, Nile red staining, and gravimetric method. Results generated from FT-IR spectra differentiated KACC microalgae based on their biochemical contents with Scenedesmus rubescens KACC 2 and Chlorococcum sp. KACC 13 possessed high total protein and lipid content, respectively. Nile red fluorescence at 530/575 nm showed the yellow fluorescence under a fluorescent microscope giving the evidence of high neutral lipids in 10 KACC microalgae isolates. Total lipid content showed prominent variation between the KACC isolates and found in the range of 4 to 32% of DW. Lipid productivity and biomass productivity showed a similar pattern among KACC strains. Thus, our findings serve as a baseline data on the bioprospecting potential of KACC isolates from river Noyyal, an unexplored area of Western Ghats.

The aim of this paper was to investigate the optimum transesterification method for the production of biodiesel from microalgae. Chlorococcum sp. and Scenedesmus sp. cultivated in secondary treated municipal wastewater and in 1/3N BG-11 medium, respectively, were selected for the conversion of their lipids by one- and two-step transesterification processes. Sulfuric acid and sodium hydroxide catalysts were separately employed in one-step transesterification process, and a two-stage process employing the basic catalyst followed by the acidic one in the second step was also used. The quality of the produced biodiesel was strongly determined by the catalyst used. The analysis of fatty acid methyl esters of the Chlorococcum sp. lipids showed that the two-step process has similar effects compared with one-step with acid (21.56 and 21.85 mg of fatty acid methyl esters (FAMEs), respectively). On the other hand, better results were obtained through the two-step process with the Scenedesmus sp. (40.51 mg of FAMEs), compared with one-step methods with acid and base catalysts (9.57 and 22.3 mg of FAMEs, respectively). The type of methyl esters produced is strongly depended on the type of algal species and growth conditions.

Made available in DSpace on 2022-04-29T08:36:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-12-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Apoio à Pesquisa do Estado da Paraíba Ministério da Ciência, Tecnologia e Inovação Financiadora de Estudos e Projetos Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) The effects of digested microalgae biomass of Chlorella vulgaris, Desmodesmus maximus, Chlorococcum sp. cf hypnosporum, and Spirulina platensis or fructooligosaccharides on human colonic microbiota during in vitro fermentation (48 h) were evaluated. Fructooligosaccharides and digested microalgae biomass increased Lactobacillus-Enterococcus and Bifidobacterium relative abundances and decreased Prevotellaceae-Bacteroidaceae, Clostridium histolyticum, and Eubacterium rectale-Clostridium coccoides. The digested microalgae biomass s showed a higher prebiotic index than fructooligosaccharides, evidenced through the higher selective stimulation of beneficial microorganisms and inhibition of undesirable bacteria on colonic microbiota. S. platensis biomass contained nystose, raffinose, and phenolics, increased the relative abundance of Lactobacillus-Enterococcus and Bifidobacterium, and decreased Eubacterium rectale-Clostridium coccoides, Clostridium histolyticum, and Prevotellaceae-Bacteroidaceae. After 24 h of incubation, the medium fermented with S. platensis promoted an increase in the concentration of acetic and propionic acids. D. maximus biomass showed higher insoluble fibers and kestose, the greatest Lactobacillus-Enterococcus relative abundance, and increases in the butyric and propionic acids after 48 h. C. vulgaris biomass showed the highest glucose and fructose concentrations, some phenolics, and the highest Bifidobacterium relative abundance after 48 h. Laboratory of Microbial Processes in Foods Department of Food Engineering Center of Technology Federal University of Paraíba Laboratory of Food Microbiology Department of Nutrition Health Science Center Federal University of Paraíba Laboratory of Reef Environments and Biotechnology with Microalgae - Exact and Natural Sciences Center Federal University of Paraíba Department of Food Technology Federal Institute of Sertão de Pernambuco Department of Food and Nutrition School of Pharmaceutical Sciences São Paulo State University Federal Institute of Paraná Campus Paranavaí Department of Food and Nutrition School of Pharmaceutical Sciences São Paulo State University Financiadora de Estudos e Projetos: 255709 CNPq: 303437/2017-0 CNPq: 405644/2018-3

Different microalgae species produce varying quantity and quality of the lipids. Fatty acid methyl ester composition, which comprises both saturated and unsaturated contents, critically affects biodiesel properties. Current study compares six locally isolated microalgae strains belonging to three classes (Trebouxiophyceae, Chlorophyceae, and Cyanophyceae) on the basis of lipid content and biodiesel properties. All the six species are grown in similar condition up to the late stationary phase, and their lipid content and fatty acid methyl ester composition are measured experimentally. Multi-criteria decision analysis (MCDA) tool has ranked Calothrix species (class Cyanophyceae) on the top, owing to better cetane number, density and oxidation stability; whereas Chlorococcum species (class Chlorophyceae) is ranked second because of its higher lipid content, better cold flow property, and low viscosity. Property analysis of these two species is extended in the enlarge temperature range for five properties, vapor pressure, latent heat of vaporization, liquid density, liquid viscosity and vapor diffusivity, which are important in spray and combustion modeling. It is found through detailed property estimation that Chlorococcum sp. is a more suitable species in comparison with Calothrix sp. as it is having better properties and its lipid content is much higher than that of Calothrix sp. Although the properties of microalgae biodiesel are poorer in comparison with conventional diesel fuel, a greater number of such studies will help in understanding the requisite changes as required for microalgae biodiesel-based engine and their properties as compared with conventional diesel.

The study explored the chronic toxicity of triclosan to green microalga Chlorococcum sp. under multiple interactions among multiple environmental conditions. This is the first study on chronic algal toxicity to combine synchrotron-based Fourier transform infrared spectromicroscopy, factorial analysis, principal component analysis, and stepwise-cluster analysis. Such a combination helps to reveal the toxic mechanism at the molecular level and explore the inner correlationship among multiple environmental conditions. In the 120-h test, nitrogen content became the most significant factor of the physiochemical properties. Some insignificant factors in the 48-h test became significant in the 120-h test. Temperature * nitrogen content, temperature * phosphorus content, and pH * phosphorus content were the most significant two-order interactions. Temperature * pH * NaCl concentration and temperature * NaCl concentration * phosphorus content were the most significant three-order interactions. More high-order interactions became significant in the 120-h test, indicating the complexity and impacts of all the factors may increase when time was extended. The chronic toxicity of triclosan presented more distinguishable variations among treatments based on biochemical alterations. These results demonstrate that the sensitivity and fragility of algae to triclosan can be amplified with time extension. Long-term exposure can be applied to better evaluate and predict the environmental toxicity behavior of triclosan. It can also help with environmental evaluation and risk management of real-world triclosan toxicity.

The individual and combined effects of micronutrients and hormones on freshwater-borne microalgae growth were investigated for biofuel feedstock in this experimental study. Five algal strains of Chlorella sp., Chlorococcum sp., Phormidium sp., Chlorella sp. and Cosmarium sp., AZH, AZS, ZAA1, ZAA2, and ZAA3, respectively, have been investigated. These strains were treated using different concentrations of micronutrients (iron chloride, manganese chloride, and sodium molybdenum oxide) and hormone (salicylic acid). The different treatments’ growth effects were as follows: iron chloride &gt, sodium molybdenum oxide ˃ manganese chloride &gt, salicylic acid. The order of the increases in the number of microalgal strain cells achieved by the application of the micronutrients and hormone was AZH &gt, AZS &gt, ZAA3 &gt, ZAA2 &gt, ZAA1. The combined treatments produced higher growth rates than the individual treatments, with the order of their effects being micronutrients + hormone &gt, all three micronutrients &gt, hormone alone. The increase in the number of microalgal strain cells under combined treatment was ZAA3 &gt, AZH &gt, ZAA2 and assessed using one-way ANOVA.

Algae are considered pigment-producing organisms. The function of these compounds in algae is to carry out photosynthesis. They have a great variety of pigments, which can be classified into three large groups: chlorophylls, carotenoids, and phycobilins. Within the carotenoids are xanthophylls. Xanthophylls (fucoxanthin, astaxanthin, lutein, zeaxanthin, and β-cryptoxanthin) are a type of carotenoids with anti-tumor and anti-inflammatory activities, due to their chemical structure rich in double bonds that provides them with antioxidant properties. In this context, xanthophylls can protect other molecules from oxidative stress by turning off singlet oxygen damage through various mechanisms. Based on clinical studies, this review shows the available information concerning the bioactivity and biological effects of the main xanthophylls present in algae. In addition, the algae with the highest production rate of the different compounds of interest were studied. It was observed that fucoxanthin is obtained mainly from the brown seaweeds Laminaria japonica, Undaria pinnatifida, Hizikia fusiformis, Sargassum spp., and Fucus spp. The main sources of astaxanthin are the microalgae Haematococcus pluvialis, Chlorella zofingiensis, and Chlorococcum sp. Lutein and zeaxanthin are mainly found in algal species such as Scenedesmus spp., Chlorella spp., Rhodophyta spp., or Spirulina spp. However, the extraction and purification processes of xanthophylls from algae need to be standardized to facilitate their commercialization. Finally, we assessed factors that determine the bioavailability and bioaccesibility of these molecules. We also suggested techniques that increase xanthophyll's bioavailability. The research leading to these results was funded by Xunta de Galicia supporting the Axudas Conecta Peme, the IN852A 2018/58 NeuroFood Project and the program EXCELENCIAED431F 2020/12; to Ibero-American Program on Science and Technology (CYTED—AQUA-CIBUS, P317RT0003) and to the Bio Based Industries Joint Undertaking (JU) under grant agreement No 888003 UP4HEALTH Project (H2020-BBI-JTI-2019). The JU receives support from the European Union’s Horizon 2020 research and innovation program and the Bio Based Industries Consortium. The project SYSTEMIC Knowledge hub on Nutrition and Food Security, has received funding from national research funding parties in Belgium (FWO), France (INRA), Germany (BLE), Italy (MIPAAF), Latvia (IZM), Norway (RCN), Portugal (FCT), and Spain (AEI) in a joint action of JPI HDHL, JPI-OCEANS and FACCE-JPI launched in 2019 under the ERA-NET ERA-HDHL (nº 696295). info:eu-repo/semantics/publishedVersion

There is a growing trend to explore microalgae as an alternative resource for the food, feed, pharmaceutical, cosmetic and fuel industry. Moreover, the polar lipidome of microalgae is interesting because of the reports of bioactive polar lipids which could foster new applications for microalgae. In this work, we identified for the first time the Chlorococcum amblystomatis lipidome using hydrophilic interaction liquid chromatography-high resolution electrospray ionization- tandem mass spectrometry (HILIC–HR–ESI–MS/MS). The Chlorococcum amblystomatis strain had a lipid content of 20.77% and the fatty acid profile, determined by gas chromatography-mass spectrometry, has shown that this microalga contains high amounts of omega-3 polyunsaturated fatty acids (PUFAs). The lipidome identified included 245 molecular ions and 350 lipid species comprising 15 different classes of glycolipids (6), phospholipids (7) and betaine lipids (2). Of these, 157 lipid species and the main lipid species of each class were esterified with omega-3 PUFAs. The lipid extract has shown antioxidant activity and anti-inflammatory potential. Lipid extracts also had low values of atherogenic (0.54) and thrombogenic index (0.27). In conclusion, the lipid extracts of Chlorococcum amblystomatis have been found to be a source of lipids rich in omega-3 PUFAs for of great value for the food, feed, cosmetic, nutraceutical and pharmaceutical industries.

In this chapter, we are putting our focus on biologically active compounds that are taken from natural resources, specifically compounds that act on molecular targets and are involved in several diseases in the human body. One of the most well-known biologically active compounds is astaxanthin, which is a xanthophyll carotenoid found in Haematococcus pluvialis, Chlorella zofingiensis, Chlorococcum and Phaffia rhodozyma. Astaxanthin has shown to provide a wide range of beneficial health benefits on the metabolism and in several organ systems of the human body including cardiovascular diseases, neurological disorders, endocrine diseases, ophthalmic diseases, rheumatological diseases, dermatological diseases, immunological diseases, nephrological disorders and obstetrics and gynaecological conditions, including pre-eclampsia and fertility. Additionally, astaxanthin has shown to provide a comprehensive set of activities which are beneficial to the human body such as anti-cancer activity, anti-inflammatory activity, anti-apoptotic activity, anti-oxidant activity and anti-cancer activity. Moreover, astaxanthin is found to be effective in enhancing sports performance during physical activity and therapeutic for the smoking population due to the high anti-oxidant activity found in astaxanthin.

Cellulase has gained interest in researchers due to its great applicability in the field of biotechnology. The Bacillus licheniformis KY962963 used in the study was isolated from Chlorococcum sp. Optimization of various physical parameters like pH, temperature, salinity and effect of co-inducers on the cellulase production (FPase and CMCase) was carried out. In crude enzyme extracts, the selected bacterial strain exhibited higher endoglucanase (CMCase) activity as compared to total cellulase activity (FPase). The highest production of cellulase was obtained with Bacillus licheniformis KY962963 when 1% (w/v) cellulose and 0.5% (w/v) peptone as co-inducers was used at 37 °C, pH 7.0, 72 h of production time where CMCase activity was found to be of 7.72 IU/ml and FPase 6.19 IU/ml. The conditions were optimized using OVAT approach which were further validated through statistical modeling. The methods used in this study has established its suitability to optimize cellulase production for its industrial applicability.

In this study, Chlorococcum sp. was investigated for its cholinesterase inhibitory potentials and antioxidant activity. The algal sample was cultivated, harvested, and extracted sequentially using n-hexane, dichloromethane, and ethanol. The extracts were characterized using Fourier transmission infra-red (FTIR) and Gas Chromatography-Mass Spectrometry. The metal chelating, radical scavenging activities, as well as anticholinesterase potentials of the algal extract, was also investigated. FTIR characterization of the microalgal biomass revealed the presence of phenolic compounds, alkaloids, polysaccharides, and fatty acids. The extracts showed the presence of phytol, neophytadiene, butylated hydroxyl toluene, and 3-tert-butyl-4-hydroxyanisole. The ethanol extract showed the highest DPPH (IC50 = 147.40 µg/ml) and OH (IC50 = 493.90 µg/ml) radical scavenging and metal chelating (IC50 = 83.25 µg/ml) activities. Similarly, the ethanol extract (IC50 = 13.83 µg/ml) exhibited the highest acetylcholinesterase inhibitory activity, while the dichloromethane extract showed the highest butyrylcholinesterase inhibitory activity. All the extracts exhibited antioxidant properties and inhibitory effects against butyrylcholinesterase and acetylcholinesterase; however, ethanol extracts showed better activity. PRACTICAL APPLICATIONS: Biomass obtained from some microalgal species is commonly used as dietary supplements and nutraceuticals due to the presence of high-valued products. However, the antioxidant and anticholinesterase activities of biomass from Chlorococcum sp. have not been explored. Chlorococcum sp. extracts contain some antioxidants such as 3-tert-Butyl-4-hydroxyanisole, butylated hydroxytoluene, phytol, and neophytadiene. Characterization of the extracts also revealed the presence of phenolic compounds, polysaccharides, and fatty acids. These compounds may contribute to the observed antioxidant and anticholinesterase activities of Chlorococcum sp. The result of this study suggests that Chlorococcum sp. may contain some nutraceuticals which could be used as antioxidants and cholinesterase inhibitors.

Bioprospection of novel autochthonous strains is key to the successful industrial-scale production of microalgal biomass. A novel Chlorococcum strain was recently isolated from a pond inside the industrial production facility of Allmicroalgae (Leiria, Portugal). Phylogenetic analysis based on 18S ribosomal ribonucleic acid (rRNA) gene sequences suggests that this isolate is a novel, free-living Oophila amblystomatis strain. However, as our phylogenetic data strongly suggests that the aforementioned taxon belongs to the genus Chlorococcum, it is here proposed to rename this species as Chlorococcum amblystomatis. In order to characterize the biotechnological potential of this novel isolate, growth performance and biochemical composition were evaluated from the pilot (2.5-m3) to industrial (10-m3) scale. The highest maximum areal productivity (36.56 g&middot, m&minus, 2&middot, day&minus, 1) was reached in a 10-m3 tubular photobioreactor (PBR), as compared to that obtained in a 2.5-m3 PBR (26.75 g&middot, 1). Chlorococcum amblystomatis displayed high protein content (48%&ndash, 56% dry weight (DW)) and moderate levels of total lipids (18%&ndash, 31% DW), carbohydrates (6%&ndash, 18% DW) and ashes (9%&ndash, 16% DW). Furthermore, the lipid profile was dominated by polyunsaturated fatty acids (PUFAs). The highest pigment contents were obtained in the 2.5-m3 PBR, where total chlorophylls accounted for 40.24 mg&middot, g&minus, 1 DW, followed by lutein with 5.37 mg&middot, 1 DW. Overall, this free-living Chlorococcum amblystomatis strain shows great potential for nutritional applications, coupling a promising growth performance with a high protein content as well as relevant amounts of PUFAs, chlorophyll, and carotenoids.

Mn-promoted nickel-based catalysts were explored for the direct hydrogenation of microalgae (Chlorococcum sp.) containing 49.6% of carbohydrates in water. With this catalyst at 250 °C for 3.0 h, microalgae was completely decomposed, where the conversion of microalgae to liquid products (CTL) and the total yield of polyols reached 66.9%, and 53.6%, respectively. Among polyols, the total yield of 1,2-propanediol and ethylene glycol were 41.7%. XRD, XPS and TEM-EDX characterizations showed that 5% of Mn addition, 350 °C of reduction temperature and the co-precipitation synthesis ensured the excellent dispersion of the Ni catalyst with small particle sizes. The Mn promoter was found to stabilize the catalyst structure by preventing the Ni particles from aggregation and to effectively promote retro-aldol and dehydroxylation reaction due to the increasing number of Lewis acid sites. Meanwhile, the hydrogenation pathways over nickel-based catalysts were proposed.

Five common used green algae species, Chlorella vulgaris, Chlorococcum sp. GD, Parachlorella kessleri TY, Scenedesmus obliquus, and Scenedesmus quadricauda, were evaluated for their growth and nitrogen removal properties when being cultivated in synthetic wastewater with ammonium and nitrate as nitrogen sources. The five microalgae could adapt wastewater with different kinds of nitrogen sources, but the growth potential and nitrogen removal ability were species-dependent. Parachlorella kessleri TY cultivated in wastewater with ammonium and nitrate had higher biomass concentration of 2750 and 2765 mg L−1, respectively, compared to C. vulgaris, S. obliquus, and S. quadricauda. Chlorococcum sp. GD in wastewater with nitrate had the highest biomass concentration of 3095 mg L−1. Although all microalgae showed a good removal efficiency of nitrogen (ammonium: 85.30–97.03%; nitrate: 100%) after 7 days of cultivation, Chlorococcum sp. GD and P. kessleri TY removed 85–90.24% of ammonium and 100% of nitrate within 2–3 days, which was faster than the other three microalgae. It was also found that the growth and pollutant removal of microalgae in wastewater with nitrate was superior to those of microalgae in wastewater with ammonium. This was caused by the inhibitory effect of the low pH when microalgae were cultivated in wastewater with ammonium as the nitrogen source. Based on the results above, the growth and nitrogen removal was closely related to the microalgal species and the pH of the wastewater.

Photoautotrophic cultivation of Chlorococcum humicola was performed in batch and continuous modes in different cultivating system arrangements to compare biomass and carotenoids' concentration and their productivities. Batch result from stirred tank and airlift photobioreactors indicated the positive effect of increasing light intensity on growth and carotenoid production, whereas the finding from continuous cultivation indicated that carotenoid enhancement preferred high light intensity and nitrogen-deficient environment. The highest biomass (1.31 ± 0.04 g L-1) and carotenoid (4.59 ± 0.06 mg L-1) concentration as well as the highest productivities, 0.46 g L-1 d-1 for biomass and 1.61 mg L-1 d-1 for carotenoids, were obtained when maintaining high light intensity of 10 klx, BG-11 medium and 2% (v/v) CO2 simultaneously, while the highest carotenoid content (4.84 mg g-1) was associated with high light intensity and nitrogen-deficient environment, which was induced by feed-modified BG-11 growth medium containing nitrate 20 folds lower than the original medium. Finally, the cultivating system arranged into smaller stirred tank photobioreactors in series yielded approximately 2.5 folds increase in both biomass and carotenoid productivities relative to using single airlift photobioreactor with equivalent working volume and similar operating condition.

This study investigated the toxicity of triclosan to the green microalga Chlorococcum sp. under multiple environmental stressors. The interactions between triclosan and environmental stressors were explored through full two-way factorial, synchrotron-based Fourier transform infrared spectromicroscopy and principal component analyses. Phosphorus concentration, pH * phosphorus concentration, and temperature * pH * NaCl concentration were the most statistically significant factors under triclosan exposure. The variation of those factors would have a huge impact on biophysiological performances. It is interesting to find Chlorococcum sp. may become more resistant against triclosan in phosphorus-enriched environment. Besides, particular significant factors from multiple environmental stressors showed the impacts of triclosan on the corresponding response of Chlorococcum sp. owing to the specific structure and performance of biomolecular components. Moreover, two high-order interactions of temperature * pH * NaCl concentration and temperature * pH * NaCl concentration * phosphorus concentration had more contributions than others at the subcellular level, which could be attributed to the interactive complexity of biomolecular components. Due to cellular self-regulation mechanism and short exposure time, the biophysiological changes of Chlorococcum sp. were undramatic. These findings can help reveal the interactive complexity among triclosan and multiple environmental stressors. It is suggested that multiple environmental stressors should be considered during ecological risk assessment and management of emerging pollutants.

Nowadays, halal products are gaining wider recognition as a new benchmark for safety and quality assurance. As a consequence the commercial development of microalgae is established due to their high value chemicals, for examples, I²-carotene, astaxanthin, phycobilin pigments and algal extracts for cosmaceutical products. Therefore, many researchers have gained interest to study the potential of microalgae as new valuable chemicals and other product sources. The aim of the research is to explore new sources of pigments to be used as halal food colorants. This quest is not only directed in finding natural alternatives for synthetic dyes, but also to discover new taxons for the carotenoid production. Thus, there is a solid need to investigate the potential of natural pigments, particularly carotenoids in microalgae to be fully utilised and commercialised especially in halal market, health advantages, food products and dye technology. A total of 6 species was evaluated for quantitative and qualitative carotenoid composition, namely, Chlorella fusca , Chlorella vulgaris , Selenastrum capricornutum , Pandorina morum , Botryococcus sudeticus and Chlorococcum sp. The main carotenoids identified in all species through HPLC analysis were lutein, I²-cryptoxanthin and I²-carotene. The ratio of these carotenoids varies between species. Lutein was detected substantially higher in Chlorella fusca (69.54±11.29 µg/g DW); I²-cryptoxanthin in Pandorina morum species (1.24±0.33 µg/g DW) whereas I²-carotene in Chlorella vulgaris (18.42±9.2 ug/g DW). The significant outcome of the research will be new findings of new natural carotenoid pigment sources as potential food colorants and bioactive compounds which can be beneficial to halal health promoting products industry.

Although pharmaceuticals and personal care products have been used and introduced into the environment in large quantities, little information on potential ecological risks is currently available considering their effects on living organisms. We verified the feasibility of using synchrotron-based Fourier Transform Infrared (SR-FTIR) spectromicroscopy to explore in vivo toxic effects on single living Chlorococcum sp. cells. The study provided important information to achieve a better understanding of the toxic mechanism of triclosan and carbamazepine on living algae Chlorococcum sp.. Triclosan and carbamazepine had distinctive toxic effects on unicellular living algae. Most strikingly, triclosan had more dramatic toxic effects on biochemical components than carbamazepine. Triclosan can affect algae primarily by inhibiting fatty acid synthesis and causing protein aggregation. The toxicity response was irreversible at higher concentration (100.000 μM), but attenuated at lower concentration (0.391 μM) as time extended. Carbamazepine can produce hydrophobic interactions to affect the phospholipid bilayer and work on specific proteins to disfunction the cell membrane. Carbamazepine-exposed cells developed a resistance while extending exposure time. This is the first demonstration from an ecological standpoint that SR-FTIR can provide an innovative approach to reveal the toxicity of emerging pollutants in aquatic environments.

Selection of suitable strain of microalgae is the crucial factor for large-scale production of algae-based products. Efforts have been made here for isolation, identification and biochemical characterization of five microalgae strains collected from Tripura (a small state in north-eastern region of India). Two Chlorococcum sp. (NITAAP008 and NITAAP019) demonstrate their high lipid (15–24%), equal amounts of carbohydrate and protein (35–40%), with specific growth rate of 0.13 day−1. These strains are potential resource for biofuel production. After lipid extraction, remaining biomass can be used as source of carbohydrate for the production of other biofuels. One isolated strain is identified as Chlorella sp. (NITAAP009) and shows 22–33% carbohydrate, 41–50% protein and 5% chlorophyll with specific growth rate of 0.125 day−1. Another Chlorella sp. (NITAAP011) isolated from lake area exhibits significant chlorophyll (5–6.4%), 30–50% carbohydrate, 48–60% protein and low lipid (1–10%) with lower specific growth rate (0.10 day−1). Both strains are having industrial competence for chlorophyll production due to their synthesizing ability of significant amount of chlorophyll (5–6.4%). The last one, Korshikoviella sp. (NITAAP017), has 15–18% lipid, 22–34% carbohydrate, 30–43% protein and 3–4% chlorophyll with specific growth rate of 0.12 day−1 and can be used for food supplement production or lipid synthesis. © 2017 Curtin University of Technology and John Wiley & Sons, Ltd.

Sulfate is a primary sulfur source and can be available in wastewaters. Nevertheless, effect of sulfate ions on growth and pollutants removal of microalgae seems to be less investigated. At the present study, self-flocculating microalga Chlorococcum sp. GD was grown in synthetic municipal wastewater with different sulfate concentrations. Results indicated that Chlorococcum sp. GD grew better in synthetic municipal wastewater with 18, 45, 77, 136 and 271mg/L SO42- than in wastewater without SO42-. Chlorococcum sp. GD had also excellent removal efficiencies of nitrogen and phosphorus and effectively flocculated in sulfate wastewater. Sulfate deprivation weakened the growth, pollutants removal and self-flocculation of Chlorococcum sp. GD in wastewater. Antioxidative enzymes activity significantly increased and photosynthetic activity significantly decreased when Chlorococcum sp. GD was cultivated in sulfate-free wastewater. Sulfate deprivation probably reduced cell activity of growth, pollutants removal and flocculation via inducing the over-accumulation of reactive oxygen species (ROS).

Chlorococcum sp . has been studied as its possibility for biofuel feedstock. This alga was grown in Zarrouk media. After harvesting, lipid extraction was done by pure n-hexane and mixture of chloroform: methanol (2 : 1)) and hexane: ethanol (3 : 1). Highest oil recovery (21.20%) derived from chloroform: methanol (2 : 1) solvent system from dry biomass whereas the lowest (2.83%) came from n-hexane: ethanol solvent system from wet biomass. GC/MS used for the analysis of extracted lipid revealed that, palmitic acid methyl ester (C 17 H 34 O 2 ), 9-octadecenoic acid methyl ester (C 19 H 36 O 2 ) were major contents of this biofuel. The acquired fatty acid profile indicates that Chlorococcum sp. could be used as promising biofuel feedstock in near future. Journal of Bangladesh Academy of Sciences, Vol. 40, No. 2, 147-153, 2016

Sensitivity of tropical freshwater microalgae (Mesotaenium sp., Chlorococcum sp. and Scenedesmus sp.) to environmentally relevant concentrations of hexavalent chromium (Cr6+) and cadmium (Cd2+) was compared individually in three growth media viz. Bold’s Basal Medium (BBM), Test Medium 1 (TM1) and Test Medium 2 (TM2) based on fluorescence reduction. Free metal content of growth media was determined by Visual MINTEQ (version 3.1). After 24 h, relative fluorescence of microalgae in the three media decreased with increased metal concentration showing a concentration dependent graded toxicity response. All microalgae were more sensitive to the metals when grown in TM1, when compared, more sensitive to Cr6+ than Cd2+. Metal speciation indicated that TM1 and TM2 media have higher percentage of bioavailable Cd2+ than BBM, and chromium was present mainly as CrO42− and HCrO4−. The results suggest that the TM1 medium is more suitable under short term exposure of microalgae to metals in environmental monitoring.

The study was conducted to evaluate the conditions to enhance the accumulation of lipids and starch in Chlorococcum sp. TISTR 8583 for the production of biofuel. The Chlorococcum sp. TISTR 8583 was cultivated on BG-11 medium under optimized light intensity. The nitrogen limitation (NL) enhanced the accumulation of both starch and lipids and resulted in 34.02% total sugars as compared to 22.57% on nitrogen supplemented (NS) media only. Similarly, the nitrogen supplemented (NS) media produced 17.05% lipids as compared to 29.59% lipids by NL media. The biomass was investigated for biodiesel and bioethanol production by adopting different pretreatment strategies, such as enzyme, acid and alkaline pretreatments. The alkaline pretreatment was found to be efficient strategy (23.67 wt% sugars/g algal biomass: 1.2% (w/v) at 140 ⁰C for 30 min) while the acid pretreatment (1%: v/v; 140 °C) was least effective pretreatment strategy with the yield of 14.83 wt% sugars/g algal biomass. Keywords: Microalgae, Pretreatments, Biofuel, Starch, Lipids

Microalgae are a diverse group of photosynthetic eukaryotic organisms that are widely distributed globally. They are prolific sources of highly valuable compounds with fascinating chemical structures. Due to their balanced nutritional compositions and health benefits, they are increasingly being used as functional food ingredients. Carotenoid-based pigments and polyunsaturated fatty acids (PUFAs) are examples of high-value nutrients that can be accumulated abundantly in microalgae. Here, the effects of potassium chloride-induced stress on the productions of lipids and carotenoids in the green microalga of the Chlorococcaceae family were investigated. Under normal BG11 medium, this green microalga strain TISTR 9500 accumulated high levels of PUFA and primary carotenoid lutein. Stress tests revealed that KCl enhanced and modulated lipid and carotenoid accumulation levels. The liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis revealed that secondary carotenoids astaxanthin and canthaxanthin were robustly produced under KCl stress with the similar content of lutein. Further, this stress led to a significant increase in the total FA amount with the higher proportion of unsaturated FA than saturated FA. Thus, this green microalga could be an attractive and alternative natural biosource for canthaxanthin and astaxanthin, as well as for functional lipids.

The physicochemical characteristics, antioxidant and antitumor activities of partial purified exopolysaccharides from microalgae Chlorella pyrenoidosa FACHB-9, Scenedesmus sp. and Chlorococcum sp. were investigated. The molecular weights were 1.94 × 105, 7.39 × 103 and 3.24 × 104 g/mol, respectively. Monosaccharide analysis indicating that these exopolysaccharides consisted of ten different kinds of sugars and derivatives, respectively. Furthermore, they exhibited obvious free radicals scavenging abilities, which reached to 55.2–71.4% and 63.1–77.5% on DPPH and hydroxyl radicals, respectively. Moreover, the antitumor effects were investigated using human colon cancer cell lines HCT116 and HCT8. The results showed that they had significant antitumor effects considering the inhibitory effects on cell viabilities (17.2–19.2% on HCT116, and 22.9–38.6 on HCT8, respectively), and could decrease the colony amounts (21–42.8% on HCT116, and 11.5–35.2% on HCT8, respectively) at the tested dosage. Thus, these exopolysaccharides may be worth further investigating as effective potential antitumor agents.

Evaluation of 50 nm zinc oxide nanoparticles’ (ZnO-NPs) effects on the microalgae Chlorococcum sp. growing in high salt growth medium (HSM) was investigated by using flow cytometry parameters (cell size (FSC), granularity (SSC), chlorophyll a fluorescence (FL3), and formation of reactive oxygen species (ROS)). Algal cells in exponential growth were exposed to 0–100 mg/L of ZnO-NPs and their physiological responses were measured after 24 and 96 h of treatment. Behavior of ZnO-NPs was analyzed in HSM and results indicated that ZnO-NPs formed agglomeration with a large distribution. Total soluble Zn concentration increased when initial ZnO-NP concentration increased. Significant negative effect on algal cells was observed after 96 h exposition and at high ZnO-NP concentration. This negative impact was evaluated by the significant increase in ROS production, inhibition in the photosynthetic electron transport, and reduction in cell growth. In this study, using flow cytometry multi-parameters might help to prevent and evaluate inhibitory effect of oxide nanoparticles on aquatic photosynthetic microorganisms.

Microalgae are at the start of the food chain, and many are known producers of a significant amount of lipids with essential fatty acids. However, the bioactivity of microalgal lipids for anti-inflammatory and antithrombotic activities have rarely been investigated. Therefore, for a sustainable source of the above bioactive lipids, the present study was undertaken. The total lipids of microalga Chlorococcum sp., isolated from the Irish coast, were fractionated into neutral-, glyco-, and phospho-lipids, and were tested in vitro for their anti-inflammatory and antithrombotic activities. All tested lipid fractions showed strong anti-platelet-activating factor (PAF) and antithrombin activities in human platelets (half maximal inhibitory concentration (IC50) values ranging ~25&ndash, 200 &mu, g of lipid) with the highest activities in glyco- and phospho-lipid fractions. The structural analysis of the bioactive lipid fraction-2 revealed the presence of specific sulfoquinovosyl diacylglycerols (SQDG) bioactive molecules and the HexCer-t36:2 (t18:1/18:1 and 18:2/18:0) cerebrosides with a phytosphingosine (4-hydrosphinganine) base, while fraction-3 contained bioactive phosphatidylcholine (PC) and phosphatidylethanolamine (PE) molecules. These novel bioactive lipids of Chlorococcum sp. with putative health benefits may indicate that marine microalgae can be a sustainable alternative source for bioactive lipids production for food supplements and nutraceutical applications. However, further studies are required towards the commercial technology pathways development and biosafety analysis for the use of the microalga.

Harvesting of the micro alga Chlorococcum sp. R-AP13 through autoflocculation, chemical flocculants or by change in medium pH was evaluated. Surface charge of algal cells changed in response to the method used and affected flocculation efficiency. While aluminum sulfate and FeCl3 supported 87% and 92% efficiency, auto flocculation could recover 75% of biomass in 10min. Maximum efficiency (94%) was obtained with change in medium pH from 8.5 to 12.0 achieved through addition of 40mgl(-1) of NaOH. Since high concentrations of FeCl3 and AlSO4 were toxic to the cells, flocculation induced by pH change may be considered the most effective strategy. Residual medium after flocculation could be reused efficiently for algal cultivation, minimizing the demand for fresh water.

Microalgae are extensively used in the remediation of heavy metals like iron. However, factors like toxicity, bioavailability and iron speciation play a major role in its removal by microalgae. Thus, in this study, toxicity of three different iron salts (FeSO4, FeCl3 and Fe(NO3)3) was evaluated towards three soil microalgal isolates, Chlorella sp. MM3, Chlamydomonas sp. MM7 and Chlorococcum sp. MM11. Interestingly, all the three iron salts gave different EC50 concentrations; however, ferric nitrate was found to be significantly more toxic followed by ferrous sulphate and ferric chloride. The EC50 analysis revealed that Chlorella sp. was significantly resistant to iron compared to other microalgae. However, almost 900 μg g−1 iron was accumulated by Chlamydomonas sp. grown with 12 mg L−1 ferric nitrate as an iron source when compared to other algae and iron salts. The time-course bioaccumulation confirmed that all the three microalgae adsorb the ferric salts such as ferric nitrate and ferric chloride more rapidly than ferrous salt, whereas intracellular accumulation was found to be rapid for ferrous salts. However, the amount of iron accumulated or adsorbed by algae, irrespective of species, from ferrous sulphate medium is comparatively lower than ferric chloride and ferric nitrate medium. The Fourier transform infrared spectroscopy (FTIR) analysis shows that the oxygen atom and P = O group of polysaccharides present in the cell wall of algae played a major role in the bioaccumulation of iron ions by algae.

Microalgal cultivation has attracted global attention in recent years. It is a worldwide rapidly growing business sector due to the numerous applications of microalgae biomass and the valuable natural by-products. Some of these products are used in pharmaceutical, biomedical, cosmetic, and food industries, and recently in biofuel production. The cost reduction of microalgal biomass production is an essential factor, and many studies have been focused on microalgae cultivation in wastewater. The selection of microalgae for biomass and lipid production is a very crucial factor. Chlorococcum sp. are common microalgae, found in wastewater. The aim of this study was to investigate the effect of initial biomass concentration, air supply, and type and duration of light exposure of Chlorococcum sp. cultures in a high nutrient concentration synthetic wastewater. Experiments were conducted under controlled environmental conditions in order to investigate the removal of nutrients from wastewater, the biomass growth rates, and lipids accumulation in microalgae. The results of this study demonstrated that high initial biomass concentration is more efficient for lipid production. Specifically, higher lipids content (27.7%) was observed with high initial microalgae concentration, even though the phosphorus concentration was almost zero. Biomass production was increased faster at the higher air flow rate (6 L/min), without need for addition of carbon dioxide (CO 2 ). Τhe growth rate of Chlorococcum sp. was greater under artificial light compared to sunlight exposure, as well as the CO 2 biofixation, since it is directly related to the algal biomass.

Herein, we report a one-pot approach to produce HMF from aquatic microalgae (Chlorococcum sp.) with a yield up to 48.0% under mild reaction conditions (200 °C, 2 h) over the commercial cheap H-ZSM-5 catalyst. Conversion of microalgae to HMF involved three steps: (1) degradation of microalgae to carbohydrates; (2) hydrolysis of polysaccharides to glucose and mannose; (3) their isomerization to fructose on Lewis acid sites and its further dehydration to HMF over Bronsted acid sites. Proteins and lipids in microalgal cells play an important role in stabilizing HMF in water. Ball-milling pretreatment or addition of another organic solvent enhanced the productivity of HMF from microalgae. Besides, this cheap H-ZSM-5 catalyst also demonstrated excellent stability, and a slight loss of its activity can be easily recovered by simple calcination treatment.

A laboratory based integrated approach was undertaken for improvement of lipid accumulation in green microalgae under sodium chloride (NaCl) stress. The maximum biomass yields (1.22 ± 0.04 g L−1 in Chlorella and 1.31 ± 0.04 g L−1 in Chlorococcum) were obtained in the media with initial NaCl concentrations at 2 g L−1 (for Chlorella) and 0.05 g L−1 (for Chlorococcum) after 14 days of culture. Interestingly, maximum lipid accumulation obtained was 45.8 ± 0.4% w/v for Chlorella (on day eight) and 36.33 ± 0.56% w/v for Chlorococcum (on day ten) at an exposure of 5 g L−1 and 1.5 g L−1 NaCl concentrations, respectively. Fatty acid profiles of methyl esters for neutral and polar lipid fractions showed the presence of myristic (C14:0), palmitic (C16:0), palmitoleic (C16:1), oleic (C18:1) and linoleic (C18:2) acids as major fatty acids. Fluorescence intensities (% positive Nile red stained cells) of neutral and polar lipid fractions were also higher in NaCl stress conditions. A significant correlation between polar lipid and neutral lipid was found in both Chlorella (r2 = 0.979) and Chlorococcum (r2 = 0.972). Flow cytometric study demonstrated a positive fluorescence signal for neutral and polar lipid bodies related to Nile red fluorescence. Associated biochemical changes, like those in total chlorophyll, carotenoid, carbohydrate and protein contents, were determined under variable NaCl concentrations. The elemental compositions (CHNS) and CO2 fixation rate were assessed using high lipid yielding cells under optimum NaCl concentrations. Biodiesel fuel properties were obtained from high lipid yielding cells of the test microalgae and compared with Indian and international diesel standards. Finally large-scale cultivation of Chlorella ellipsoidea was performed in a hybrid photobioreactor (800 L capacity) and the highest biomass and lipid content obtained was 1.66 ± 0.09 g L−1 (at 8 days) and 54.73 ± 1.78% w/v (at 10 days) at 5 g L−1 NaCl respectively. This optimized NaCl concentration makes it an economical substitute for biodiesel production on a large scale.

Optimisation of bioelectricity production from microalgae in double chamber algal fuel cell was investigated. Ten microalgae were isolated from pond and sea water and characterised molecularly. They were identified as follow: Nanochloropsis sp MG257918, Chlorella sorokiniana MG257919 and Coelastrella sp. MG257917. Others include Chlorococcum sp MG257921, Neosdesmus pupukensis MG257914, Chlorella vulgaris MG257915, Leptolyngbya boryana MG257913, Chlamydopodium starrii MG257920, Parachlorella sp. MF114127 and Neochloris aquatica MG257916. The potential of these microalgae to produce electricty was determined by using human urine as substrate. Three microalgae: C. vulgaris, C. sorokiniana and Parachlorella. sp with the best output were selected for optimisation under different conditions which are: pH, inoculum size, salt bridge concentration, oxidising agent and number of salt bridge. At the end of the different experiments, C. vulgaris, C. sorokiniana and Parachlorella sp. had maximum output of (1.49 V; 1.31 mA), (1.67 V; 1.4 mA) and (1.46 V; 1.25 mA) respectively. The optimum requirement for the 3 microalgae were similar: pH of 8-8.5, 10-15 ml of each algal as inoculum, 1 M KCl-based salt bridge, potassium permanganate as oxidising agent and increase in the number of salt bridges favoured optimum performance by each microalgae.

The performance of a self-flocculating microalga Chlorococcum sp. GD on the flocculation, growth, and lipid accumulation in wastewater with different ammonia nitrogen concentrations was investigated. It was revealed that relative high ammonia nitrogen concentration (20–50 mg·L−1) was beneficial to the flocculation of Chlorococcum sp. GD, and the highest flocculating efficiency was up to 84.4%. It was also found that the highest flocculating efficiency occurred in the middle of the culture (4–5 days) regardless of initial ammonia concentration in wastewater. It was speculated that high flocculating efficiency was likely related to the production of extracellular proteins. 20 mg·L−1 of ammonia was found to be a preferred concentration for both biomass production and lipid accumulation. 92.8% COD, 98.8% ammonia, and 69.4% phosphorus were removed when Chlorococcum sp. GD was cultivated in wastewater with 20 mg·L−1 ammonia. The novelty and significance of the investigation was the integration of flocculation, biomass production, wastewater treatment, and lipid accumulation, simultaneously, which made Chlorococcum sp. GD a potential candidate for wastewater treatment and biodiesel production if harvested in wastewater with suitable ammonia nitrogen concentration.

The worldwide continuous increasing of population provokes an increasing awareness about the food security. Qatar is one of the first countries establishing a Food Security Strategy Program to satisfy the demand of food and feed. Microalgae is considered as one of the most promising solution based on its ability to produce the essential elements needed for food and feed such as lipids, carbohydrates, proteins... In Qatar University, a diverse collection of Microalgae and Cyanobacteria strains isolated from different environments was established (QUCCCM). Microalgae, These photosynthetic microorganisms are capable of converting solar energy into useful compounds. Microalgae accumulate several kinds of metabolites such as proteins (6-52%), lipids (7-23%), carbohydrates (5-23%). In addition, microalgae produce have the ability to produce high-value metabolites. The aim of our work was to screen the QUCCCM and identify potential strains with high nutritional value for use as feed for poultry and livestock. In this study, Microalgal isolates belonging to 12 different species were investigated for their eligibility to be used as a feed. All strains were cultivated over a period of 10 to15 days depending on species. Optical Density and Dry weights were recorded every three days to follow the algal Growth. The results showed the presence of three categories of isolates (fast, medium and slow growing). Among them, the species Chlamydomonas sp. presented the highest growth rate (μ) with 0.89day − 1 ± 0.27 and a doubling time of 1.28/ day. Based on this result, the fast-growing strains were subjected to metabolite investigations in terms of lipids, proteins, carbohydrates, amino acids and Fatty acids to select the ideal strain(s) presenting high growth rate along with metabolites valuable for algae-based feed supplement. The highest protein and Lipid content was observed in the case of a freshwater strain belonging to the Mychonastes sp.with ∼ 50% w/w and 40.7% ± 0.015 respectively. Carbohydrates were seen highest in Chlorococcum sp.with a value of 30% ± 0.009%. Considering the marine strains, the isolates had a similar range of protein, Lipids and Carbohydrates content of (22%-34%), (32%-39%) and (8%-20%) respectively. Based on this study, one marine strain (Pichochloris sp.) having 33% ± 0.021 content of protein and 32.7% ± 0.036 as lipid, and one freshwater (Mychonastes sp.) holding the highest amount of metabolites were selected for deeply investigations in terms of FAME and Amino acid profiling which are crucial parameters that determine the feed quality. The results showed the presence of different essential Amino acids in the total protein fraction. Fatty acid profiling comprised saturated and unsaturated fats for all strains; most of them being rich with C18:0; C16:0 and C16:3. For the selected strains, the metabolite content during the growth period was followed by sampling every 3 days in order to identify the stage having high productivity and rich metabolite content. The analysis of the isolates showed an increase in the production of each metabolite during the growth, wherein lipids and protein amounts are relatively high while carbohydrates were comparatively low. These two selected strains will be improved in terms of lipid and protein production using media and salinity stress in order to enhance the production of essential nutrients such as omegas, amino acids and used for animal bioassay. In Conclusion, this study showed the existence of a diverse and rich collection of valuable strains with important metabolites that can support the country's food security program, by providing microalgae to supplement animal feed. Additionally, the potential candidates can be used for commercial applications.

A simple and high-throughput method for determining in situ intracellular neutral lipid accumulation in Chlorella ellipsoidea and Chlorococcum infusionum with flow cytometry and confocal microscopy was established by employing different solvents and a lipophilic dye, Nile red. Seven different organic solvents, acetic acid, dimethyl sulfoxide (DMSO), acetone, methanol, ethanol, n-hexane, and chloroform at different concentrations ranging from 0 to 80% (v/v) were tested. The fluorescence signal for neutral lipids was collected with a 586/42 emission filter (PE-A) and the maximum fluorescence intensity (% grandparent) was measured as 74.01 ± 4.82% for Chlorella and 70.1 ± 5.52% for Chlorococcum at 30% acetic acid (v/v). The statistical analysis of Nile red-stained cells showed a high coefficient of variation (CV), standard deviation (SD), mean, and median values in the acetic acid-based staining method, followed by DMSO, n-hexane and chloroform. Confocal microscopy revealed a high rate of accumulation of cytosolic neutral lipids when stained with Nile red and other organic solvents. Higher lipid accumulation in Fesupplemented conditions was also detected and a maximum lipid content of 57.36 ± 0.41% (4-fold) in Chlorella and 48.20 ± 0.43% (4-fold) in Chlorococcum were measured at 0.001 g/L of ferrous sulfate (FeSO4). High fluorescence intensity (75.16 ± 0.24% in Chlorella and 72.24 ± 1.07% in Chlorococcum) in Fe-treated cells confirmed the efficiency of the staining procedure.

Chlorococcum sp., grape marc, and Pinus radiata have been reacted in a semi-continuous (flow through) system at 425 °C under a flow of N 2 or H 2 and results compared to those from batch autoclave experiments. This paper concentrates on the structure of the condensate, which is more useful and more amenable to analysis. Under similar reaction conditions, the flow through system gave lower yields of dichloromethane soluble materials plus water plus gas for Chlorococcum sp. than a batch autoclave, higher yields for P. radiata , and similar yields of the same fraction for grape marc. Two distinct condensate phases (organic and aqueous) were produced, the composition and amount of which depended on the biomass type and the gas atmosphere (N 2 or H 2 ). Constituents of the original biomass were often better preserved in the flow-through than in batch autoclave reactions under similar conditions.

Cylindrospermopsin (CYN) is a toxic secondary metabolite produced by filamentous cyanobacteria which could work as an allelopathic substance, although its ecological role in cyanobacterial-algal assemblages is mostly unclear. The competition between the CYN-producing cyanobacterium Chrysosporum (Aphanizomenon) ovalisporum, and the benthic green alga Chlorococcum sp. was investigated in mixed cultures, and the effects of CYN-containing cyanobacterial crude extract on Chlorococcum sp. were tested by treatments with crude extracts containing total cell debris, and with cell debris free crude extracts, modelling the collapse of a cyanobacterial water bloom. The growth inhibition of Chlorococcum sp. increased with the increasing ratio of the cyanobacterium in mixed cultures (inhibition ranged from 26% to 87% compared to control). Interestingly, inhibition of the cyanobacterium growth also occurred in mixed cultures, and it was more pronounced than it was expected. The inhibitory effects of cyanobacterial crude extracts on Chlorococcum cultures were concentration-dependent. The presence of C. ovalisporum in mixed cultures did not cause significant differences in nutrient content compared to Chlorococcum control culture, so the growth inhibition of the green alga could be linked to the presence of CYN and/or other bioactive compounds.

BACKGROUND The quality and quantity of lipids in microalgae mainly depend on nitrogen and phosphorous supply. In the present study, growth of newly isolated microalgal strain, Chlorococcum sp. IM-03 has been studied under nitrogen stressed conditions. Fluorescence microscopy and Fourier transform infrared spectroscopy have been used to observe changes in lipid and carbohydrate content. RESULTS Growth of selected species is monitored in terms of dry biomass and chlorophyll content under varying sodium nitrate concentration, viz. 0, 100 and 1500 mg L−1 (designated as N0, N100 and N1500, respectively). N100 was selected in the experimental plan as similar levels were observed in domestic wastewater, which can be used as possible culture media for mass cultivation. Maximum chlorophyll concentration (72.65 µg mg−1) was found at N100. It was also observed that cultivation at N100 resulted in highest lipid content of 17.8%. Carbohydrate content was 18% at N100 with moderate increase to 19.8% at N1500. CONCLUSIONS On the basis of the current study, it can be concluded that sodium nitrate concentration of 100 mg L−1 (N100) offers enhanced production of lipids in Chlorococcum sp. without compromising growth. © 2015 Society of Chemical Industry

Twelve indigenous microalgae, comprising of three fresh water and nine marine strains, were evaluated for their potential as source of dietary polyunsaturated fatty acids (PUFAs) under autotrophic growth conditions. The microalgal lipids showed higher content of omega-3 PUFAs as reflected in lower omega-6 to omega-3 ratios between 0.1 and 0.75. Alpha linolenic acid (ALA), was the predominant omega-3 PUFA in fresh water green algal strains. Scenedesmus dimorphus and Chlorococcum sp. showed higher content of ALA with an average productivity of 3 mgL−1 day−1. Long chain omega-3 PUFAs, eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) were observed in marine strains. Nannochloropsis and Chlorella sp. had higher content of EPA with Chlorella sp. showing an average productivity of 2 mgL−1 day−1. Isochrysis sp. showed higher DHA content with average productivity of 0.37 mgL−1 day−1. Presence of EPA and DHA contributed to higher degree of unsaturation in lipids of marine strains. Among the marine strains, the growth and lipid profile of Nannochloropsis sp. and Chlorella sp. remained unaffected by growth medium, whereas strains like T. theli showed a differential response to media. Spirulina platensis SP6 from CFTRI algal culture repository was also included as a reference strain since its nutritional benefits have been well elucidated. Gamma Linolenic acid (GLA) was the predominant PUFA in Spirulina sp. with an average productivity of 0.73 mgL−1 day−1.

Identification of cost-effective cell disruption methods to facilitate lipid extraction from microalgae represents a crucial step in identifying promising biofuel-producing species. Various cell disruption methods including autoclaving, microwave, osmotic shock, and pasteurization were tested in the microalgae Chlorococcum sp. MCC30, Botryococcus sp. MCC31, Botryococcus sp. MCC32, and Chlorella sorokiniana MIC-G5. Lipid content (on dry weight basis) from the four cultures on day 7 ranged from 11.15 to 48.33%, and on day 14 from 11.42 to 44.26%. Among the methods tested, enhanced lipid extraction was achieved through osmotic shock (15% NaCl) for Botryococcus sp. MCC32, microwave (6 min) for Botryococcus sp. MCC31, osmotic shock (5% NaCl) for Chlorella sorokiniana MIC-G5 and microwave (2 min) for Chlorococcum sp. MCC30. The highest palmitate (16:0) contents (25.64% and 34.20%) were recorded with osmotic shock (15% NaCl) treatment for Botryococcus sp. MCC32 and microwave (6 min) for Botryococcus sp. MCC31, respectively. Two strains, along with their respective cell disruption methods, were identified as promising oil blends or nutraceuticals due to their high unsaturated fatty acid (UFA) content: Botryococcus sp. MCC31 (37.6% oleic acid content; 39.37% UFA) after autoclaving and Botryococcus sp. MCC32 after osmotic shock of 15% NaCl treatment (19.95% oleic acid content; 38.17% UFA).

The catalytic valorization of microalgae, a sustainable feedstock to alleviate dependence on fossil fuel and offset greenhouse gases emissions, is of great significance for production of biofuels and value-added chemicals from aquatic plants. Here, an interesting catalytic process is reported to convert microalgae (Chlorococcum sp.) into 1,2-propanediol (1,2-PDO) and ethylene glycol (EG) in water over nickel-based catalysts. The influences of reaction temperature, initial H2 pressure and reaction time on the product distribution were systematically investigated by using a batch reactor. Under optimal reaction conditions (at 250 °C for 3 h with 6.0 MPa of H2 pressure), microalgae were directly and efficiently converted over a Ni–MgO–ZnO catalyst and the total yield of polyols was up to 41.5%. The excellent catalytic activity was attributed to the smaller size and better dispersion of Ni particles on the MgO–ZnO supporter based on the characterization results as well as its tolerance to nitrogen-containing compounds. Besides, the reaction pathway was proposed based on the formation of reaction intermediates and the results of model compound conversion.

One-step and Two-step methods were studied for lipid extraction from wet and unbroken (water content is 65-67%) Chlorella sp. and Chlorococcum sp. (GN38) using deep eutectic solvent (DES) treated microalgae cells. Further we optimized the extraction process and studied on its underlying mechanism. Among all DES, Choline chloride-Acetic acid (Ch-Aa) DES treatment showed optimal conditions at the mass ratio of DES: methanol-H2SO4 (2.00%) mixture: algae biomass was 60:40:3 with reaction time was 60min, and the optimum temperature was 110°C (Chlorococcum sp.) and 130°C (Chlorella sp.) respectively. The total content of FAME by One-step method with DES treatment was improved by 30% compared with Two-step method. This process is effective on wet and unbroken paste of microalgae biomass, so the FAME extracted using one-step with DES process is feasible for microalgae based biodiesel production.

Carotenoids are lipophilic pigments found in plants and algae, as well as some bacteria, archaea, and fungi that serve two functions&mdash, (1) as light harvesting molecules&mdash, primary carotenoids, and (2) as antioxidants, acting against reactive oxygen species&ndash, secondary carotenoids. Because of their strong antioxidant properties, they are also valuable for the development of anti-aging and photo-protective cosmetic applications. Of particular interest is the carotenoid phytoene, for its colorless and UV absorption characteristics. In this study, we targeted a reduction of phytoene desaturase (PDS) activity with the pigment-inhibiting herbicide 1-methyl-3-phenyl-5-[3-(trifluoromethyl)phenyl]pyridin-4-one (fluridone), which leads to the over-accumulation of phytoene in the recently characterized microalgal strain Chlorococcum sp. (UTEX B 3056). After post-incubation with fluridone, phytoene levels were measured at ~33 ug/mg cell tissue, as opposed to non-detectable levels in control cultures. Hence, the novel microalga Chlorococcum sp. is a viable candidate for the production of the high-value carotenoid phytoene and subsequent applications in cosmeceuticals, as well as more obvious nutraceutical and pharmaceutical applications.

In the present study, ten microalgal strains found in fresh and saline waters were cultured, and used to conduct batch experiments in order to evaluate their potential contribution to nutrient removal and biofuel production. The growth rate of microalgae was inversely analogous to their initial concentration. Three freshwater strains were selected, based on their growth rate, and their behavior with synthetic wastewater was further investigated. The strains studied were the Scenedesmus rubescens (SAG 5.95), the Neochloris vigensis (SAG 80.80), and the Chlorococcum spec. (SAG 22.83), and higher growth rate was observed with S. rubescens. Total phosphorus removal at an initial phosphate concentration of 6-7 mg P/L in the synthetic wastewater, was 53%, 25% and 11% for N. vigensis, Chlorococcum spec., and S. rubescens, respectively. Finally, the lipid content was determined at 20th and 30th day of cultivation, and the highest amount was observed at the 20th day.

Algae-derived biofuels are increasingly seen as an alternative source of energy with potential to supplement the world's ever increasing demand. A great challenge exists today in energy input and costs to procure algal lipid from a cultivated suspension, which generally requires steps such as concentration, filtration, dewatering, grinding, and solvent extraction. Using well practiced sand filtration and ozonation processes, we sought to reduce processing steps and streamline the operations in one vessel. The specific Chlorococcum aquaticum suspension was acidified to pH 3.3 to promote agglomeration prior to biomass collection by sand filtration. The algae-loaded filter bed was drained of free water and added with methanol and ozonated for 2 min to rupture the cell membrane to accelerate release of cellular contents. The methanol solution containing the dissolved lipid product was collected by draining, while the filter bed was regenerated by further ozonation when needed. The results showed 95% collection of the algal biomass from the suspension and a 16% yield of lipid from the algae, as well as restoration of filtration velocity of the sand bed via ozonation. GCMS identification of the extract showed primary products in the forms of long-chain largely saturated hydrocarbons of 16 to 20 carbons. The new technique streamlines individual steps in the procurement of algal lipid from the suspension that is potentially an improvement over existing energy-intensive methods.

Cost-efficient harvesting of microalgae is a major challenge due to their small size and often low concentration in the culture medium. The flocculation efficacy of different inorganic and organic amendments was evaluated on various microalgae genera—one strain each belonging to Chlamydomonas, Chlorococcum, two of Botryococcus, and of Chlorella. An improvised medium comprising of commercial grade urea, single super phosphate, and muriate of potash was used to grow the microalgae for flocculation experiments. High pH induced increased flocculation efficiency (72–76 %) in selected microalgal strains. Ferric chloride was found to be the most efficient for most of the microalgal strains, while maize starch and rice starch proved superior for Chlorella sp. MCC6 and Botryococcus sp. MCC32. Although the highest flocculation efficiency was obtained with inorganic flocculant, i.e., ferric chloride (87.3 %) with Botryococcus MCC31, this was comparable with rice starch (86.8 %) for Botryococcus MCC32. This study showed that widely available cheaper biopolymers such as rice starch, maize, and potato starch can be promising flocculants due to their better harvesting efficiency (>80 %) and low price, thereby contributing to economical production of biodiesel from algae.

Five indigenous microalgal strains of Scenedesmus, Chlorococcum, Coelastrum, and Ankistrodesmus genera, isolated from Indian fresh water habitats, were studied for carbon-dioxide tolerance and its effect on growth, lipid and fatty acid profile. Scenedesmus dimorphus strain showed maximum growth (1.5 g/L) and lipid content (17.83% w/w) under CO2 supplementation, hence selected for detailed evaluation. The selected strain was alkaline adapted but tolerated (i) wide range of pH (5–11); (ii) elevated salinity levels (up to 100 mM, NaCl) with low biomass yields and increased carotenoids (19.34 mg/g biomass); (iii) elevated CO2 levels up to 15% v/v with enhancement in specific growth rate (0.137 d−1), biomass yield (1.57 g/L), lipid content (19.6% w/w) and CO2 biofixation rate (0.174 g L−1 d−1). Unsaturated fatty acid content (alpha linolenic acid) increased with CO2 supplementation in the strain.