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The unicellular green alga Oophila amblystomatis was named by Lambert in 1905 based upon its association with egg masses of the spotted salamander Ambystoma maculatum. We collected algal cells from Lambert's original egg capsule preparations that were contributed to Phycotheca Boreali‐Americana (PBA) in 1905 and subjected them to DNA extraction and PCR with O. amblystomatis‐specific 18S rRNA gene primers. DNA amplified from these preparations was cloned and nine clones were sequenced. Along with representative sequences from the Oophila clade and Chlorophyceae, a phylogenetic tree was inferred. Seven sequences clustered within the Oophila clade and two clustered with Chlamydomonas moewusii, which is included in a sister clade to Oophila. By sequencing algal material from the egg capsules of representative type material we can unambiguously characterize O. amblystomatis and define a monophyletic clade centered on this type material. Accordingly, we reject a recent proposal that this species be transferred to Chlorococcum. [ABSTRACT FROM AUTHOR]

As microalgas são microrganismos heterogêneos, versáteis e disponíveis em todo o mundo. Seu uso tem sido descrito em várias áreas, com vários objetivos, especialmente na remediação de resíduos de variadas origens. Neste artigo, é apresentado um levantamento bibliográfico de trabalhos publicados em periódicos de alto impacto, utilizando como critério de pesquisa as palavras chave “chlorococcum” e “bioproducts”. Posteriormente, esses trabalhos foram filtrados, sendo considerados apenas aqueles publicados em revistas com fator de impacto igual ou superior a 5. Por último, foi realizada uma triagem dos resultados para separar artigos de pesquisa de artigos de revisão. Foram obtidos, após a pesquisa em três bases de dados e triagem, 238 trabalhos, entre revisões e artigos de pesquisa. Ao fim dos filtros, o número final de artigos utilizados no relatório foi de 128 trabalhos. Após análise, pôde-se perceber o crescimento recente do interesse do uso de microalgas para remediação de águas residuárias e outros resíduos, bem como para a produção de moléculas de interesse, principalmente carotenoides, e também do uso dessa biomassa para produção de combustíveis, em especial o biodiesel.

Microalgae reckon one of the most promising organisms due to their numerous applications in biotechnology, such as, their biomass utilization to extract various primary and secondary metabolites. These compounds benefit the food and pharmaceutical industries and the energy field, such as, biofuel and hydrogen gas production. Therefore, it is necessary to find various sustainable ways to actively preserve the isolates and productive strains with purity for an extended period without affecting their genetic characteristics and productive ability to grow and regenerate. The latest study aimed to compress several microalgae to form alginate beads using sodium alginate with five types of pure algal cultures, i.e., Scenedesmus quadricauda, Scenedesmus dimorphus, Chlorella vulgaris, Chlorococcum humicola, and Chlamydomonas sp. The vitality and activity of all the strains studied through the storage period showed the success of preparing alginate beads and staying viable for 18 months at 4 °C in the refrigerator under dark conditions. Therefore, encapsulating microalgae with sodium alginate is a possible and helpful method for preserving algae isolates for a prolonged period in a pure form. The survival of algae in alginate beads is an essential step to apply in the future as one of the viable methods to preserve pure algae isolates for a long time. [ABSTRACT FROM AUTHOR]

Two green microalgal strains, CCCryo 469-16 and CCCryo 470-16, were isolated from samples of Antarctic microflora. Their morphology and 18S rRNA sequences indicated a phylogenetic relationship with strains of the genera Chlorococcum Meneghini, Macrochloris Korshikov, and Pleurastrum Chodat. The last genus is considered particularly problematic as it underwent several revisions. Moreover, its type strain, P. insigne SAG 30.93, was recently demonstrated to coincide genetically with the authentic strain of Chlorococcum oleofaciens from an 18S rRNA phylogeny. This deprived the genus Pleurastrum of an important type reference. Thus, the molecular markers rbcL, tufA, and ITS were employed to identify the Antarctic isolates more precisely. Several other microalgae related to our isolates were obtained from international culture collections for comparison. The obtained results allowed the re-establishment of strain P. insigne SAG 30.93 as the reference strain and the definition of the molecular borders of both genera Pleurastrum and Chlorococcum. Based on our findings, several Chlorococcum species are now re-attributed to Pleurastrum, as well as Macrochloris rubrioleum, here re-named Pleurastrum rubrioleum comb. nov., to which the Antarctic isolates also belong. Finally, a relationship between Pleurastrum lineages and climate zones was established. [ABSTRACT FROM AUTHOR]

A green alga, Chlorococcum sp. (Chlorococcales, Chlorophyceae), was grown from scrapings of the travertine rocks from the outlet stream of the Emerald Pool, Khlong Thom Nuea, Khlong Thom District Krabi province in Southern Thailand – a classic karstic stream habitat. It was a recalcitrant alga: organic solvents did not extract chlorophyll (Chl) from the algae very well but heated Dimethylsulphoxide (DMSO) was effective. Rapid light curve PAM experiments were used to quantify photosynthetic parameters: Eopt = 275 ± 9.7 µmol photons m–2 s–1, ETRmax = 277 ± 5.99 µmol e– g–1 Chl a s–1, photosynthetic efficiency (Alpha, α0) = 2.248 ± 0.112 e– g–1 Chl a. For Chlorococcum sp. deliberately grown in very low light, Eopt = 290 ± 4.89 µmol photons m–2 s–1 but ETRmax = 109 ± 0.97 µmol e– g–1 Chl a s–1, Alpha (α0) = 1.010 ± 0.192 e– g–1 Chl a. Overall, the amount of Chl b compared with Chl a was relatively low for most Chl a + b organisms (Chl b/a ≈ 0.21) but the ratio was not strongly affected by irradiance. The changes in ETRmax and α0 indicate that the Chlorococcum sp, responded to very low irradiance by increasing total Chl as Chl a, a marginal decrease in Chl b/a ratio but no substantial change in far-red absorption. The spectrum stripping technique confirmed Chlorococcum sp, is a Chl a + b organism albeit with a low Chl b content. Photosynthesis in this species was not very sensitive to pH in the range pH 5–9 but was inhibited at pH 10, indicating that it was very capable of using HCO3– as an inorganic carbon source. Chlorococcum has a carbon concentrating mechanism (CCM), however based on its insensitivity to the depolarizing effects of high [K+], it is unlikely to be dependent on the membrane potential across the cell membrane. The alga is homiochlorophyllous and recovers rapidly from dessication without synthesis of new chlorophyll.

Chlorococcum is a coccoid green algal genus, which contains almost 50 species. The genus is polyphyletic, but in a traditional sense, the cells are coccoid and non-motile with a cup-shape chloroplast in the vegetative stage, while the spores have chlamydomonad appearance. They are distributed worldwide mainly in terrestrial habitats, and the biotechnological potential of several strains has been reported. In this study, three new green algal strains from a shallow, temporary freshwater lake in Hungary are characterized using microscopic (light and transmission electron microscopy) and DNA-based methods (phylogenetic analysis of the ribosomal ITS region, the 18S ribosomal RNA and rbcL genes, and ITS secondary structure comparison). Based on the obtained results, one of the three new isolates is considered to represent a new species, which is described here as Chlorococcum szentendrense sp. nov. [ABSTRACT FROM AUTHOR]

Scientific and research work was carried out to determine the bioregulatory properties of Botryococcus, Chlorococcus, Tetradesmus Scenedesmus strains in plant growth. In the initial stages of the research, the influence of these microwater strains on the general germination of the seeds of the medium-ripe cotton variety "Bukhara-10" was studied, in which the international gene bank stored in the scientific laboratory "Biotechnology" of the Tashkent Institute of Chemical Technology was studied. Registered microalgae were used as main objects in our research.

Chlorococcum novae-angliae is a terrestrial green microalgae species with remarkable potential to synthesize omega-3 (ω-3) and omega-6 (ω-6) fatty acids. In this study, Chlorococcum novaeangliae has been subjected to varying growth conditions (light, nitrogen, salinity, and temperature) to investigate the accumulation of ω-3 and ω-6 fatty acids. Among tested growth conditions, eicosapentaenoic acid, a-linoleic acid, ω-linoleic acid, and arachidonic acid were enhanced by nitrogen limitation. Significant increases were observed in concentration of linoleic acid, an essential precursor molecule for the production ω-6 fatty acids under decreased nitrogen concentrations. Despite the lowest biomass growth, monounsaturated fatty acids and docosahexaenoic acid were increased by 14.4% and 8.7% under low light intensities, respectively. Meanwhile, the highest concentrations of palmitic acid (C16:0), stearic acid (C18:0), and oleic acid (18:1cis-9) were also detected under nitrogen limitation. Total accumulation of ω-3 fatty acids was highest in the control group, followed by nitrogen limitation, whereas total ω-6 fatty acid accumulation was highest under nitrogen limitation followed by the control group. Total lowest fatty acid concentrations were obtained under increased salinity while low temperature conditions heavily inhibited cellular growth. [ABSTRACT FROM AUTHOR]

Two green microalgal strains, CCCryo 469-16 and CCCryo 470-16, were isolated from samples of Antarctic microflora. Their morphology and 18S rRNA sequences indicated a phylogenetic relationship with strains of the genera Chlorococcum Meneghini, Macrochloris Korshikov, and Pleurastrum Chodat. The last genus is considered particularly problematic as it underwent several revisions. Moreover, its type strain, P. insigne SAG 30.93, was recently demonstrated to coincide genetically with the authentic strain of Chlorococcum oleofaciens from an 18S rRNA phylogeny. This deprived the genus Pleurastrum of an important type reference. Thus, the molecular markers rbcL, tufA, and ITS were employed to identify the Antarctic isolates more precisely. Several other microalgae related to our isolates were obtained from international culture collections for comparison. The obtained results allowed the re-establishment of strain P. insigne SAG 30.93 as the reference strain and the definition of the molecular borders of both genera Pleurastrum and Chlorococcum. Based on our findings, several Chlorococcum species are now re-attributed to Pleurastrum, as well as Macrochloris rubrioleum, here re-named Pleurastrum rubrioleum comb. nov., to which the Antarctic isolates also belong. Finally, a relationship between Pleurastrum lineages and climate zones was established.

[Display omitted] • Effects of white LEDs and fluorescent lamps on biomass production and carotenoid content in C. humicola. • Daylight LED increases biomass production by 36% compared to fluorescent lamps. • Daylight LED yields higher lutein (1.04 mg/g) and carotenoid (3.86 mg/g) than fluorescent (0.75 mg/g). • Daylight LED reduces energy consumption, offering efficient algal cultivation. This study compares the performance of white light emitting diodes (LEDs) and fluorescent lamps for cultivating Chlorococcum humicola (C. humicola) as aquaculture feed. Results demonstrate that daylight LEDs are seen to yield the highest biomass concentration at 1,010 ± 11 mg/L, exceeding fluorescent lamps by 36 %. Switching to daylight LEDs increased carotenoid content in algal biomass from 2.97 ± 0.23 to 3.86 ± 0.15 mg/g and carotenoid concentration from 2.21 ± 0.16 to 3.90 ± 0.27 mg/L: increases of 36 % and 76 %, respectively. Blue and daylight LEDs proved to be most effective for lutein induction, with less impact on beta-carotene. Biomass under daylight LEDs shows promising values for protein and lipid contents of 32 % and 11 % dry weight, respectively. Daylight LEDs consumed less than half the energy of fluorescent lamps. Daylight LEDs significantly enhance the growth and carotenoid content of C. humicola , offering a sustainable alternative for aquaculture feed production. [ABSTRACT FROM AUTHOR]

Incessant depletion of fossil fuels urges the governments and non-governmental organizations to invest more on renewable energy sectors including generation of biofuels such as bioethanol. Production of ethanol from algal feedstock has been an interesting area of research in recent times. In the present investigation, feedstock of a green alga Chlorococcum minutum was selected for ethanol production and compared with feedstock of model alga Chlamydomonas reinhardtii. Both the species were grown under in vitro conditions using universal tris-acetate-phosphate (TAP) medium with various concentrations and combinations of vitamins such as thiamin, biotin and cobalamin (B1, B7 and B12) to enhance the biomass in turn reducing sugars in both the algal cultures. Later, these algal feedstocks were used for the production of ethanol under fermentation conditions using yeast. Reducing sugars were more in both the algal cultures grown in Cr3 or Cm3 media (TAP with 0.8 g/L of B1, 0.004 g/L of B7 & 0.004 g/L of B12) and also in Cr2 or Cm2 media (TAP with 0.4 g/L of B1, 0.002 g/L of B7 & 0.002 g/L of B12). In extent, the enhancement of ethanol production was noticed in C. reinhardtii (33.57 g/L) and C. minutum (46.97 g/L) from the feedstocks grown in Cr3 or Cm3 media when compared with feedstocks grown in other vitamin combinations or without vitamin assistance. Specifically, feedstock of C. minutum generated more output at 48 h when compared with model alga. The present work may be useful for the production of ethanol at a commercial level. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Some strains of brown hydra (Hydra vulgaris) are able to harbor the green algae Chlorococcum in their endodermal epithelial cells as symbionts. However, the relationship between brown hydra and chlorococcum is considered to be incipient symbiosis because most artificially introduced symbionts are not stable and because symbiotic H. vulgaris strains are rare in the wild. In this study, we compared the gene expression levels of the newly established symbiotic hydra (strain 105G), the native symbiotic strain (J7), and their non-symbiotic polyps to determine what changes would occur at the early stage of the evolution of symbiosis. We found that both the 105G and J7 strains showed comparable expression patterns, exhibiting upregulation of lysosomal enzymes and downregulation of genes related to nematocyte development and function. Meanwhile, genes involved in translation and the respiratory chain were upregulated only in strain 105G. Furthermore, treatment with rapamycin, which inhibits translation activity, induced the degeneration of the symbiotic strains (105G and J7). This effect was severe in strain 105G. Our results suggested that evolving the ability to balance the cellular metabolism between the host and the symbiont is a key requirement for adapting to endosymbiosis with chlorococcum. [ABSTRACT FROM AUTHOR]

The present study aims to demonstrate the potential of microalgae Chlorococcum humicola for treatment of dairy industry effluent and reduction of its pollution load with the cultivation of microalgae in the same effluent. Dairy industry wastewater supplies the required nutrients for the growth of C. humicola and its growth was comparatively higher in 50 % dairy industry effluent as compare to Bold basal growth medium. Optimization of growth parameters of algae showed that growth of C. humicola was favoured by alkaline pH and optimum growth was observed at pH 8, whereas acidic pH does not favour the growth of selected algae. The exponential growth phase of C. humicola was achieved between 3-7 days, at 20˚C temperature, a further increase in temperature decreases the algal growth. The results for the effect of different concentration of dairy wastewater (0, 10, 25, 50, 75 and 100 %) on biochemical content (protein, chlorophyll a, carbohydrate) of C. humicola revealed that 50 % wastewater concentration was more efficient for enhancement of biochemical content of microalgae as compare to control. The result further showed considerable reduction in the organic pollution load of dairy wastewater as biological oxygen demand (BOD) and chemical oxygen demand (COD) reduced to 72 and 78 % respectively, after 15 days of treatment with C. humicola. The results also showed a reduction in the nutrient concentration of dairy wastewater such as nitrate, phosphate and sulphate by 92, 43, 62 % respectively, after 10 days of treatment and 96, 67 and 78 % respectively, after 15 days of microalgal treatment as compared to control (without microalgae). These findings suggested that dairy industry wastewater was a good nutrient supplement and can be directly used for mass cultivation of C. humicola without requiring additional nutrient supplements and also the microalgae C. humicola has a great potential for the treatment of dairy industry wastewater

Cost is the crucial impediment in commercializing microalgal biodiesel. Therefore, cultivating microalgae in cost-effective nutrients reduces the upstream process cost remarkably. Thus, in this study, sugar cane bagasse hydrolysate (SBH) as a lucrative carbon supplement for Chlorococcum sp. and subsequent lipid extraction via an optimized solvent system for biodiesel production was investigated. Characterization of SBH revealed the presence of various monosaccharides and other sugar derivatives such as glucose, fructose, xylose, arabinose, etc. The maximum dry cell weight of 1.7 g/L was estimated in cultures grown in 10 mL SBH. Different solvents such as diethyl ether (DEE), chloroform (CHL), ethyl acetate (ETA), hexane (HEX), methanol (MET), ethanol (ETOH), acetone (ACE) and also combination of solvents (2:1 ratio) such as DEE: MET, CHL: MET, HEX: MET, HEX: ETOH was tested for lipid extraction efficacy. Among solvents used, 12.3% and 18.4% of lipids were extracted using CHL and CHL: MET, respectively, from 10 mL SBH amended cultures. However, the biodiesel yield was found to be similar at about 70.16 % in both SBH and no SBH-added cultures. The fatty acid profile of the biodiesel shows palmitic, oleic, linoleic, linolenic, and arachidonic acid as principal fatty acids. Further, the levels of SFAs, MUFAs, and PUFAs in 10 mL SBH-added cells were 24.67, 12.89, and 34.24%, respectively. Eventually, the fuel properties of Chlorococcum sp. biodiesel, satisfying international biodiesel standards, make the biodiesel a viable diesel substitute in the future. • Chlorococcum sp. was cultivated in sugar cane bagasse hydrolysate (SBH). • Several single and binary solvents was tested for lipid extraction efficacy in Chlorococcum sp. • The maximum DCW of 1.7 g/L and 18.7% lipid was noticed in 10 mL SBH-grown cells. • A 12.3 and 18.4% lipids was recovered by CHL and CHL:MET solvents, respectively. • SBH grown cells showed desirable fatty acids, and fuel properties as biodiesel standards. [ABSTRACT FROM AUTHOR]

BACKGROUND: Light quality influences biomass and carotenoid production in microalgae, yet no information is available for Chlorococcum humicola. This work performed a series of batch cultivations of Chlorococcum humicola to assess biomass and carotenoid production in stirred tank and airlift photobioreactors under different light qualities and supplying strategies. RESULTS: White light was preferred for growth while blue light was suitable for carotenoid production during stationary phase. Batch cultivation in stirred tank photobioreactors subjected to two‐staged lighting yielded higher carotenoid productivity than single‐staged lighting, with the highest productivity obtained when providing white light at 5000 lx during growth phase and combination of white (100 000 lx) and blue (5000 lx) lights during stationary phase. Subsequent cultivation in internal‐loop airlift photobioreactors under optimal light setting based on two‐staged study produced higher biomass (855 ± 26 mg L−1) and carotenoid (8.11 ± 0.20 mg L−1 or 9.23 ± 0.23 mg g−1) than the cultivation in stirred tank systems with the same volume and operating condition. High‐performance liquid chromatography (HPLC) analysis of carotenoid from airlift photobioreactors revealed that lutein, violaxanthin and neoxanthin were major carotenoids. CONCLUSIONS: This work reported for the first time the effect of light quality and supplying strategy on growth and carotenoid production in Chlorococcum humicola. Two‐staged lighting with white light following by combination of white light at high intensity and blue light offered new strategy to improve carotenoid productivity. Cultivation in airlift photobioreactor yielded higher biomass than the cultivation in stirred tank photobioreactors and offered an alternative for future photobioreactor selection. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

SUMMARY Parachlorococcum turfosum was previously described based on morphological studies of a culture collection strain originally identified as 'Chlorococcum elkhartiense' and on an 18S rRNA gene phylogeny of a strain derived from the same original strain but from a different culture collection. However, a subsequently published 18S rRNA gene sequence was inconsistent with the original sequence. Therefore, a new 18S rRNA gene sequence was obtained from the strain from which the holotype was derived. Comparative analyses of the new sequence using the basic local alignment search tool and a newly written Perl code, ChimViewP, which visualizes nucleotide signature shifts characteristic of chimeric sequences, revealed that the sequence used in the original description was of a chimeric nature. Similar analyses also indicated that two published 'Chlamydomonas acidophila' sequences are chimeric. Phylogenetic analyses excluding all putative chimeras showed that P. turfosum belongs to Chlorococcum, and thus Chlorococcum turfosum comb. nov. is proposed. [ABSTRACT FROM AUTHOR]

In this study Chlorococcum infusionum and Scenedesmus obliquus were isolated purified and identification From the Euphrates River at the city of Nasiriyah. The water of this canals originally from Tigris River. Ch-10 culture media was used for their cultivation in suitable laboratory conditions (25c°,200μE/m2/sec) for 16:8 hrs. Light: dark. Each culture was harvested at the end of exponential phase .Organic solvents used for extraction were Ethanol Hexane and Methanol 95% to extract the crude active Intracellular and Extracellular substances, and evaporated down to dryness .Antibacterial activity of these different extracts were evaluated against 6 strains of gram positive bacteria and gram negative bacteria, Agar diffusion method was used in this evaluation. [ABSTRACT FROM AUTHOR]

Abstract Silver nanomaterials (AgNMs) of different shapes and sizes are potentially toxic to aquatic organisms. However, studies on the toxicity of AgNMs and on their shape-dependent effects on algae are scarce. The present study evaluated the effects of three AgNMs (silver nanospheres, AgNPs; silver nanowires, AgNWs; silver nanoplates, AgPLs) with different shapes coated with polyvinylpyrrolidone on the growth and photosynthetic performance of an alga, Chlorococcum infusionum. We used growth measurements and determined the photosynthetic parameters based on chlorophyll fluorescence transients in the algal cells exposed to different concentrations of the three AgNMs. The effective concentrations at 50% (EC 50) of AgNPs, AgNWs, and AgPLs were calculated to be 0.1, 0.045, and 0.021 mg/L, respectively. The results showed that the toxicity of AgNMs in C. infusionum was in the order, AgPLs (40 nm diameter) > AgNWs (21,000 nm length × 42 nm diameter) > AgNPs (57 nm diameter), based on the decrease in growth and three photosynthetic activities. We propose that the toxic potential of AgNMs is primarily dependent on their diameter and secondarily on their shape. Overall, this study provides, for the first time, a comparison of the growth and photosynthetic activities of C. infusionum exposed to AgNMs of three different shapes. Graphical abstract fx1 Highlights • Effect of shape on silver nanomaterial toxicity on algal species is limited. • Comparative toxicity of silver nanomaterials of different shapes on Chlorococcum infusionum was evaluated. • Toxicity of the silver nanomaterials in C. infusionum was in the sequence AgPLs > AgNWs > AgNPs. • Toxic potential of silver nanomaterials is primarily dependent on their diameter and secondarily on their shape. [ABSTRACT FROM AUTHOR]

Highlights • Algae C. humicola and C. vulgaris can tolerate NaCl to a concentration of 100 mM. • C. humicola exhibited high tolerance responses, biomass, lipid and proline content. • Increased cell size under NaCl treatment linked with high metabolites accumulation. • SEM-EDS spectra addresses altered essential minerals in algae under NaCl stress. Abstract In the present study, microalgae Chlorococcum humicola and Chlorella vulgaris were grown in different concentrations of NaCl (25–1000 mM) to elucidate its impact on morphology, lipid synthesis, minerals status and antioxidative responses. Scanning Electron microscopy showed distorted cell morphology and increased cell size by 33.52% (C. humicola) and 27.79% (C. vulgaris) at 100 mM NaCl. Energy Dispersive Spectroscopy data revealed reduction in mineral contents (C, S, Fe, Mg, Si, Mn and Zn) by 14–54% in both algae. Further, C. humicola was found to have high lipid content than C. vulgaris under NaCl regime. The activities of superoxide dismutase, catalase and glutathione reductase were increased by 2.5–5 folds in both algae as compared to control. The increased level of ascorbate, cysteine and proline in both algae indicated tolerance against salinity. Thus, C. humicola and C. vulgaris may exhibit dual benefits viz., high lipid production and reclamation of sodic soil. [ABSTRACT FROM AUTHOR]

The present study investigated the effect of exposure to different concentrations of Glyphosate pesticide, cadmium and chromium elements in the polluted water medium on tolerance and the effectiveness of two algae Chlorococcum humicola and Chlorella vulgaris biomass by applying different concentrations (25,50,75,100) mg/L-1 of pesticide, Cd and Cr (2.5, 7.5, 10, 12, 15, 20 and 25) (1, 2, 3, 4, 5) mg/L-1 respectively, with exposure time (3, 6, 9 and 12) days under laboratory conditions of the temperature of 25± 2°C, the intensity of light 3000 lux with 16 hours of light and 8 darkness and pH 7± 2 in static medium. The results showed that of the algae species used in the study was characterized by the ability to tolerate the Glyphosate pesticide concentrations of (25 - 100) mg/L-1 as well as the ability of the C.humicola to tolerate high concentrations of cadmium (2.5, 7.5, 10, 12.5, 15, 20, 25) mg/L-1 while the ability of C.vulgaris to tolerate concentrations less than cadmium (2.5, 7.5, 10,12.5) mg/L-1 and the ability of the two algae to tolerate concentrations of chromium (1, 2, 3, 4, 5) mg/L-1. [ABSTRACT FROM AUTHOR]

A green and holistic approach is proposed for inhibitive performance of methanolic extract of microalgae Chlorococcum sp. (MEC), effectively contributed by levoglucosenone and hexadecanoic acid for corrosion resistance on mild steel under acidic environment. Inhibition properties of these bioactive compounds are demonstrated by gravimetric (weight loss), electrochemical (Tafel polarization, impedance spectroscopy) and surface morphological analysis (scanning electron microscopy and atomic force microscopy) that support excellent adsorption potential. The maximum inhibition efficiency is obtained ~96% at 11.7 ppm MEC in 1 M HCl at 303 K. The theoretical calculation is investigated by Density Functional Theory (DFT) to understand the intra molecular charge transfer in aqueous environment as well as the electrostatic interaction between inhibitor molecules and metallic surface. Microstructural analysis is carried out to corroborate the consequence of surface corrosion at different time interval up to three days consecutively. The inexpensive inhibitor extracted from Chlorococcum sp., exhibited an enormous strength for large scale utilization in metal corrosion inhibition under acidic medium. [ABSTRACT FROM AUTHOR]

The study provides a new insight into the impact of Se on green algae Chlorocouyeoccum littorale and effects of Se on antioxidant system and bioaccumulation. Se positively promoted C. littorale growth at lower concentrations (≤50 mg L−1), acting as an antioxidant through the inhibition of lipid peroxidation (LPO) and intracellular reactive oxygen species (ROS). The antioxidative effect was associated with an increase in guaiacol peroxidase (GPX), catalase (CAT), superoxide dismutase (SOD) and photosynthetic pigments. Meanwhile, significant increase in the cell growth rate and organic Se content was also detected in the algae. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

It is estimated that the fossil fuel reserves are going to deplete continuously due to extensive usage. In order to cope with this crisis, it is necessary to increase the efforts towards production of biofuels such as biological hydrogen (H 2 ). It is well-known fact that the biological hydrogen is a clean and ideal energy and liberates high amount of energy per unit mass. Several groups are working for the large scale production of H 2 chemically and also using photosynthetic organisms, but output is not satisfactory. The best way to achieve enhancement of H 2 is through altering the photosynthetic process by applying various stress conditions or by natural selection. In the process of selection, Chlorococcum minutum was found with improved H 2 output when compared to model green alga Chlamydomonas reinhardtii in a massively parallel and competitive high-throughput screen of different green algae. Both the species belongs to class chlorophyceae of green algae and live in fresh water conditions. In extent various light, pH and temperature conditions were applied and achieved the enhancement of H 2 production in this species under in vitro settings. Augmented hydrogenase activity was found in Chlorococcum minutum when compared to model alga and this may be one of the reason behind improved H 2 output. Hence this species may be considered as one of the best species with respect to H 2 production and also this work may be useful for future renewable energy research. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 271 mg/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). [ABSTRACT FROM AUTHOR]

In molecular phylogenetic trees of zoospore-producing unicellular chlorophycean algae, well-resolved lineages often do not correspond to current taxonomic categories, and therefore characterising diagnostic morphological traits of lineages can be challenging. We employed a phylogenetic framework to examine the evolution of light microscopic (LM) and transmission electron microscopic (TEM) features in the phylogroup Moewusinia and a related genus and then assessed the features that could be used to diagnose lineages. Most LM characters were homoplasies, but particular character states uniquely supported lineages. Autospores arranged in isobilateral tetrads made up a suitable generic feature; whereas, tetrahedral tetrads or indefinite groups of autospores were not. Some chloroplast phenotypes lacked phylogenetic signal, especially the sponge-like form previously used to define genera. Pyrenoid types characterised clades at different depths. TEM features of zoospores (i.e. papillar shape, cell wall layers, nuclear position and components of the basal apparatus) were generally consistent with clades. The sawhorse-shaped distal connecting fibre with beam-like extensions was characteristic of some phylogroups. Ultrastructural components of sexual reproduction may serve as a marker at deeper phylogenetic depths. Within Moewusinia, the saline habitat was restricted to one clade. In total, nine phylogenetic clades were defined at generic rank using phenotypic traits. Three new genera were proposed: Eubrownia gen. nov., with the new combinations E. aggregata, E. dissociata, E. illinoisensis and E. isobilateralis; Parachlorococcum turfosum gen. & sp. nov.; and Alvikia gen. nov., with the new combination Al. littoralis. Chlorococcum ( Cc.) was emended, with the new combinations Cc. aerium, Cc. macropyrenoidosum and Cc. vacuolatum. Tetracystis with the type species T. aeria was abandoned. Spongiococcum was emended with the new combination S. aplanosporum. [ABSTRACT FROM AUTHOR]

In the present work we wanted to know what happens during time to biomass and lipid productivities of Chlorococcum littorale repeatedly subjected to N-starvation. Experiments were done using repeated cycles of batch-wise N run-out (after 2 days N = 0). Two different cycles were used: repeated short-starvation (6 days of N = 0) over a total period of 72 days and repeated long-starvation (13 days of N = 0) over a total period of 75 days. Batches (using fresh inocula) were done separately as control. Shorter and longer periods of starvation showed no differences in biomass productivities and PSII quantum yield evolution. The repeated short-starvation-batches showed the same lipid productivities as the control short-starvation batches. Most importantly, the biomass lipid content was the same between control and repeated-batches. Altogether, the results point to C. littorale as a resilient and stable strain, with potential to be used under semi continuous cultivation. [ABSTRACT FROM AUTHOR]

During the cultivation of Chlorococcum humicola in photobioreactors (PBRs), significant biofilm formation occurred, leading to light limitation and lower productivity. This work presents the possibility of using commercial surfactants to reduce wall-growth biofilm in PBRs. Results confirm that sodium dodecyl sulfate (SDS) at 0.0082 mM can successfully control wall-growth biofilm in the cultivation of C. humicola more than CTAB and Triton X-100. The addition of SDS into 2-L PBRs, built from either acrylic or glass, results in 68–158 % and 28–43 % increases in algal biomass concentrations compared to those without SDS addition. PBRs applying with SDS at the start of the cultivation can be operated for 23 days without stopping aeration to remove biofilm. Both SDS and floating plastic media were effective in algal biofilm control when applying in 60-L PBRs. The addition of SDS is seen to offer a practical solution to reduce algal biofilm on both glass and acrylic surfaces and promote higher biomass concentration during the cultivation. • Algal biofilm removal using surfactants and floating plastic media. • SDS at 0.0082 mM is effective in reducing wall-growth biofilm. • Biofilm control by both methods is effective and comparable. • SDS addition does not require lengthy process optimization. [ABSTRACT FROM AUTHOR]

In the Hydra vulgaris group, only 2 of the 25 strains in the collection of the National Institute of Genetics in Japan currently show endosymbiosis with green algae. However, whether the other non-symbiotic strains also have the potential to harbor algae remains unknown. The endosymbiotic potential of non-symbiotic strains that can harbor algae may have been acquired before or during divergence of the strains. With the aim of understanding the evolutionary process of endosymbiosis in the H. vulgaris group, we examined the endosymbiotic potential of non-symbiotic strains of the H. vulgaris group by artificially introducing endosymbiotic algae. We found that 12 of the 23 non-symbiotic strains were able to harbor the algae until reaching the grand-offspring through the asexual reproduction by budding. Moreover, a phylogenetic analysis of mitochondrial genome sequences showed that all the strains with endosymbiotic potential grouped into a single cluster (cluster γ). This cluster contained two strains (J7 and J10) that currently harbor algae; however, these strains were not the closest relatives. These results suggest that evolution of endosymbiosis occurred in two steps; first, endosymbiotic potential was gained once in the ancestor of the cluster γ lineage; second, strains J7 and J10 obtained algae independently after the divergence of the strains. By demonstrating the evolution of the endosymbiotic potential in non-symbiotic H. vulgaris group strains, we have clearly distinguished two evolutionary steps. The step-by-step evolutionary process provides significant insight into the evolution of endosymbiosis in cnidarians. [ABSTRACT FROM AUTHOR]

Background: Despite extensive research in the last decades, microalgae are still only economically feasible for high valued markets. Strain improvement is a strategy to increase productivities, hence reducing costs. In this work, we focus on microalgae selection: taking advantage of the natural biological variability of species to select variations based on desired characteristics. We focused on triacylglycerol (TAG), which have applications ranging from biodiesel to high-value omega-3 fatty-acids. Hence, we demonstrated a strategy to sort microalgae cells with increased TAG productivity. Results: 1. We successfully identified sub-populations of cells with increased TAG productivity using Fluorescence assisted cell sorting (FACS). 2. We sequentially sorted cells after repeated cycles of N-starvation, resulting in five sorted populations (S1-S5). 3. The comparison between sorted and original populations showed that S5 had the highest TAG productivity [0.34 against 0.18 g l-1 day-1 (original), continuous light]. 4. Original and S5 were compared in lab-scale reactors under simulated summer conditions confirming the increased TAG productivity of S5 (0.4 against 0.2 g l-1 day-1). Biomass composition analyses showed that S5 produced more biomass under N-starvation because of an increase only in TAG content and, flow cytometry showed that our selection removed cells with lower efficiency in producing TAGs. Conclusions: All combined, our results present a successful strategy to improve the TAG productivity of Chlorococcum littorale, without resourcing to genetic manipulation or random mutagenesis. Additionally, the improved TAG productivity of S5 was confirmed under simulated summer conditions, highlighting the industrial potential of S5 for microalgal TAG production. [ABSTRACT FROM AUTHOR]

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 FeCl 3 supported 87% and 92% efficiency, auto flocculation could recover 75% of biomass in 10 min. Maximum efficiency (94%) was obtained with change in medium pH from 8.5 to 12.0 achieved through addition of 40 mg l −1 of NaOH. Since high concentrations of FeCl 3 and AlSO 4 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. [ABSTRACT FROM AUTHOR]

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 (C17H34O2), 9-octadecenoic acid methyl ester (C19H36O2) 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. [ABSTRACT FROM AUTHOR]

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 [ABSTRACT FROM AUTHOR]

The flocculating ability was an important property to microalgal harvesting, especially in secondary effluent. In this study, the flocculating ability of two microalgae, Chlorococcum sp. GD and Parachlorella kessleri TY, was evaluated after 10 d of cultivation in secondary effluent. After 180 min of settling, the flocculating ability of Chlorococcum sp. GD and P. kessleri TY was 84.43% and 16.23%, respectively. It was suggested that Chlorococcum sp. GD was an excellent self-flocculating microalgae. The mechanism on self-flocculating of Chlorococcum sp. GD was probably related to hydrophobic extracellular polymeric substances (EPS). Besides, compared to P . kessleri TY, the nitrogen and phosphorus removal efficiency of Chlorococcum sp. GD was high, which was up to 66.51% and 74.19%, respectively. Chlorococcum sp. GD also had high lipid content and biomass concentration. Therefore, Chlorococcum sp. GD could be regarded as a promising candidate for microalgal cultivation and harvesting in secondary effluent. [ABSTRACT FROM AUTHOR]