Green Alga Chlorella Research Articles

Interactive effects of temperature and bisphenol A on phytoplankton growth and community structure.

Environmental contamination of bisphenol A (BPA) is a widespread and multifaceted issue with vast ecological, social and economic consequences. Thus, understanding how local environmental conditions, such as temperature, interact with BPA to affect populations and community dynamics remain important areas of research. Here, we conduct laboratory experiments aimed at understanding how environmental gradients of both temperature and BPA concentration influence freshwater phytoplankton population growth and community structure. We exposed phytoplankton assemblages comprised of three common species of green algae (Chlorella vulgaris, Ankistrodesmus braunii and Scenedesmus quadricauda) as well as isolates of each individual species to three BPA concentrations (0, 2, 13mg/L BPA) and three temperatures (18, 23, 27°C) monitoring population growth and community structure (via biovolume). We observed antagonistic interactions between BPA and warmer temperatures, such that when warmer temperatures decreased growth (observed with A. braunii), high concentrations of BPA elevated growth at these warm temperatures; however, when warmer temperatures increased growth (C. vulgaris, S. quadricauda), high BPA concentrations diminished these gains. Although BPA exposure inhibited the growth of most C. vulgaris populations, growth was not reduced in A. braunii or S. quadricauda populations exposed to 2mg/L BPA. Phytoplankton assemblage evenness (Pielou evenness index) decreased as BPA concentration increased and was consistently lowest under 27°C. Community composition was similar in assemblages cultured under 0 and 2mg/L BPA under 18 and 23°C but was most similar between assemblages cultured under 2 and 13mg/L BPA under 27°C. These results indicate that local environmental temperatures can mediate the consequences of BPA for freshwater phytoplankton growth rates and community structure and that BPA can diminish potential gains of increased growth rate for warm-adapted phytoplankton species at high environmental temperatures.

Biotesting of Chlorella sp algae for certain medicinal drugs

In recent years, the study of drugs as pollutants in the country is gaining momentum. This is because the country does not use special wastewater treatment devices for pharmaceuticals. They enter the environment in different ways. Therefore, research on biotesting drugs in living organisms is underway. The article presents the results of experiments conducted to assess the effect of paracetamol, azithromycin, suprastin on the number and biomass of Chlorella sp algae. Chlorella sp algae are a widely used organism for biotesting. Among the above drugs in the study, paracetamol had a negative effect on the number and biomass of algae. The minimum harmful concentration of paracetamol for chlorella was 5 mg/L, the minimum harmful concentration of azithromycin for chlorella was 200 mg/L, the minimum harmful concentration of chlorella suprastin was 8 mg/L. When comparing the effect of paracetamol, azithromycin, suprastin on the number of green algae Chlorella sp, it was observed that paracetamol had the highest effect. Concentration of paracetamol 10 mg/L brought the number of chlorella close to 0. High concentrations of paracetamol and suprastinin the biomass of chlorella showed contamination of the environment.

The allelopathic algicides sanguinarine and berberine reduced the dominance of Microcystis in competition with Chlorella

Gramine, sanguinarine and berberine are potential algicides that can significantly inhibit the growth of cyanobacteria. Their effects on other phytoplankton have to be considered, because other phytoplankton species and cyanobacteria usually co-exist. In this study, we have established the relationships between phytoplankton biomasses and their marker pigments. Afterwards, we have assessed the allelopathic effects of three algicides (gramine, sanguinarine and berberine) on the mono-cultured and mixed-cultured cyanobacteria Microcystis and green algae Chlorella. Our results showed that zeaxanthine and lutein can be used to determine the cell densities of Microcystis and Chlorella in the mixed cultures, respectively. Our study also demonstrated that the inhibitory effects of these three allelopathic algicides on the growths of both Microcystis and Chlorella were sanguinarine > gramine > berberine. The concentrations for 50% of the maximal effect (EC50) of sanguinarine against Microcystis and Chlorella were 0.065 and 0.09 mg L−1, respectively; the EC50 values of gramine against Microcystis and Chlorella were 1.687 and 0.870 mg L−1, respectively; and the EC50 values of berberine against Microcystis and Chlorella were 1.969 and 2.397, respectively. The inhibitory effect of allelopathic algicides on the multiple phytoplankton species in mixed cultures was significantly greater than that in monocultures. In mixed cultures without allelopathic addition or in cultures with gramine (0.5–3 mg L−1), the dominant species was Microcystis. However, Chlorella became the dominant species when the concentration of sanguinarine was 0.1 mg L−1 or that of berberine was greater than 0.5 mg L−1. Both species of phytoplankton died completely when sanguinarine levels were greater than 0.1 mg L−1. Our results suggested that the allelopathic algicides sanguinarine and berberine reduced the dominance of Microcystis in competition with Chlorella.

Symbiont specificity differs among green hydra strains.

The symbiotic hydra Hydra viridissima has a stable symbiotic relationship with the green alga Chlorella. This hydra appears to cospeciate with the symbiotic alga, and some strains are known to have strain-specific host/symbiont combinations. To investigate the mechanism of the specificity between host and symbiont, we explored the effect of the removal or exchange of symbionts in two distantly related H. viridissima strains (K10 and M9). In the K10 strain, severe morphological and behavioural changes were found in symbiont-removed and symbiont-exchanged polyps. Interestingly, both polyps showed a similar gene expression pattern. The gene ontology (GO) enrichment analysis revealed that the removal or exchange of symbionts caused the downregulation of genes involved in the electron transport chain and the upregulation of genes involved in translation in the K10 strain. On the other hand, symbiont-removed and symbiont-exchanged M9 polyps showed modest changes in their morphology and behaviour compared with the K10 strain. Furthermore, the patterns of the gene expression changes in the M9 strain were quite different between the symbiont-removed and symbiont-exchanged polyps. Our results suggested that the regulation of energy balance is one of the crucial mechanisms for maintaining symbiotic relationships in green hydra, and this mechanism differs between the strains.

Physiological, morphological, and growth effects of microplastics on freshwater alga Chlorella vulgaris

It is doubted that large numbers of microplastics (MPs) are present in aquatic environment and their concentrations are expected to rise in the foreseeable future. Interactions, uptake, excretion rates, and the effects of microplastics on biota remain largely unrevealed. This study investigated how microplastics impact algal growth, physiological response, and the antioxidant system (superoxide dismutase “SOD”, peroxidase “POD”, catalase “CA” and glutathione reductase “GR” enzymes) using the green freshwater alga Chlorella vulgaris as the test species. MPs significantly (P < 0.05) reduced chlorophyll content, photosynthetic efficiency, photosynthetic rates, and the activities of POD, and GR. Moreover, SOD activity was significantly (P < 0.05) induced in MP-treated algae, indicating that oxidative stress was induced after exposure to MPs. Algal growth decreased with the increase in MPs, which showed that algal growth inhibition was found to be MPs’ concentration-dependent. C. vulgaris could be used as a bioindicator or a natural biomarker of contaminations in aquatic environments as it showed a range of physiological responses under MPs’ stress.Graphical abstract

Characterization of Glycolipids in the Strain Chlorella pyrenoidosa.

Plant-derived polar lipids have been reported to exhibit various beneficial effects on human health. The green alga Chlorella is known to be abundant in nutrients, including lipophilic components, and has varying nutrient content depending on the strain. In this study, to assess the nutritional functions of the strain Chlorella pyrenoidosa, we comprehensively analyzed the composition of fatty acids, polar glycerolipids, and sphingolipids. We found that n-3 polyunsaturated fatty acids (PUFAs) comprised 45.6 mol% of fatty acids in the total lipids and 62.2 mol% of n-3 PUFAs in the total lipids occurred in the glycolipids. Monogalactosyldiacylglycerol was the primary glycolipid class, and n-3 PUFA constituted 73.5 mol% of the fatty acids. Although glucosylceramide was observed in trace amounts, highly polar sphingolipids (HPSs), including glycosyl inositol phosphoryl ceramide, were found in much higher amounts compared to rice bran, which is a common source of sphingolipids. These results suggest that the examined Chlorella strain, which is abundant in glycolipids bearing n-3 PUFAs and HPS, is potentially useful as a dietary supplement for improving human health.

Supercritical methanol-induced esterification of microalgal lipids employing biomineralized cell walls as the catalyst

The methyl esterification of lipids employing supercritical methanol is an environmentally benign method since it does not produce alkaline wastewater, as is the case with conventional methods employing sodium hydroxide. Previous studies have shown that solid base catalysts are effective in decreasing reaction temperatures in the supercritical methanol methyl esterification. We focused on the coccolithophore Pleurochrysis carterae, which exhibits coccolith, i.e., CaCO3 cell walls, and confirmed that the coccoliths acted as a catalyst in the methyl esterification of lipids in P. carterae employing supercritical methanol. To confirm the catalytic effect of the coccolith, the results of the supercritical methanol reaction of extracted lipids from P. carterae without coccolith were compared. The results showed that significant differences occurred, confirming that coccolith of P. carterae acts as a catalyst. To confirm the catalytic effect of CaCO3, the main component of coccolith, the green alga Chlorella vulgaris with cellulose cell walls was used to compare non-catalyst, addition of CaCO3and addition of CaSO4–0.5H2O, which is reported to be effective. The results revealed that the amount of the product obtained from the methyl esterification of fatty acids in C. vulgaris employing CaCO3 was more significant than those obtained without any catalyst or with CaSO4–0.5H2O, indicating the effectiveness of CaCO3 as a catalyst for methyl esterification by supercritical methanol. Coccolithophores, which exhibit CaCO3 cell walls, are desirable raw materials for biofuels because they can function as catalysts.

Engineering astaxanthin accumulation reduces photoinhibition and increases biomass productivity under high light in Chlamydomonas reinhardtii

BackgroundAstaxanthin is a highly valuable ketocarotenoid with strong antioxidative activity and is natively accumulated upon environmental stress exposure in selected microorganisms. Green microalgae are photosynthetic, unicellular organisms cultivated in artificial systems to produce biomass and industrially relevant bioproducts. While light is required for photosynthesis, fueling carbon fixation processes, application of high irradiance causes photoinhibition and limits biomass productivity.ResultsHere, we demonstrate that engineered astaxanthin accumulation in the green alga Chlamydomonas reinhardtii conferred high light tolerance, reduced photoinhibition and improved biomass productivity at high irradiances, likely due to strong antioxidant properties of constitutively accumulating astaxanthin. In competitive co-cultivation experiments, astaxanthin-rich Chlamydomonas reinhardtii outcompeted its corresponding parental background strain and even the fast-growing green alga Chlorella vulgaris.ConclusionsMetabolic engineering inducing astaxanthin and ketocarotenoids accumulation caused improved high light tolerance and increased biomass productivity in the model species for microalgae Chlamydomonas reinhardtii. Thus, engineering microalgal pigment composition represents a powerful strategy to improve biomass productivities in customized photobioreactors setups. Moreover, engineered astaxanthin accumulation in selected strains could be proposed as a novel strategy to outperform growth of other competing microalgal strains.

Modeling and optimization of phycoremediation of heavy metals from simulated ash pond water through robust hybrid artificial intelligence approach

AbstractIn thermal power plants, ash pond water is being polluted with heavy metals such as Lead (II), Nickel (II), Manganese (II), Cadmium (II), Chromium (VI), and so on, through leaching from coal ash and this can eventually contaminate the groundwater. In the present study, a consortium consisting of a cyanobacterium Synechococcus sp. and green algae Chlorella sp. was used for phycoremediation of such heavy metals from simulated ash pond water. The concentrations of metals, pH and days were varied during experimentation. An accurate data‐driven artificial neural network (ANN) model was developed with the experimental data to find a relation between the input variables of the phycoremediation process with the percentage removal of the pollutants and amount of biomass produced. The optimum ANN design and ANN algorithm were evaluated using an automatic exhaustive search technique. To maximize metal removal and biomass production, a hybrid artificial neural network‐simulated annealing (ANN‐SA) optimization technique was applied to determine optimal values of input parameters. The established modeling and optimization technique is generic and can be applied to any other experimental study.

An approach towards safe and sustainable use of the green alga Chlorella for removal of radionuclides and heavy metal ions

An approach towards safe and sustainable use of the green alga Chlorella for removal of radionuclides and heavy metal ions

Effects of harvesting on morphological and biochemical characteristics of microalgal biomass harvested by polyacrylamide addition, pH-induced flocculation, and centrifugation

The effects of microalgae harvesting methods on microalgal biomass quality were evaluated using three species namely the freshwater green alga Chlorella vulgaris, marine red alga Porphyridium purpureum and marine diatom Phaeodactylum tricornutum. Harvesting efficiencies of polyacrylamide addition, alkaline addition, and centrifugation ranged from 85 to 95, 59–92 and 100%, respectively, across these species. Morphology of the harvested cells (i.e. compromised cell walls) was significantly impacted by alkaline pH-induced flocculation for all three species. Over 50% of C. vulgaris cells were compromised with alkaline pH compared to < 10% with polyacrylamide and centrifugation. The metabolic profiles varied depending on harvesting methods. Species-specific decrease of certain metabolites was observed. These results suggest that the method of harvest can alter the metabolic profile of the biomass amongst the three harvesting methods, polyacrylamide addition showed higher harvesting efficiency with less compromised cells and higher retention of industry important biochemicals.

Fe3O4-PEI Nanocomposites for Magnetic Harvesting of Chlorella vulgaris, Chlorella ellipsoidea, Microcystis aeruginosa, and Auxenochlorella protothecoides.

Magnetic separation of microalgae using magnetite is a promising harvesting method as it is fast, reliable, low cost, energy-efficient, and environmentally friendly. In the present work, magnetic harvesting of three green algae (Chlorella vulgaris, Chlorella ellipsoidea, and Auxenochlorella protothecoides) and one cyanobacteria (Microcystis aeruginosa) has been studied. The biomass was flushed with clean air using a 0.22 μm filter and fed CO2 for accelerated growth and faster reach of the exponential growth phase. The microalgae were harvested with magnetite nanoparticles. The nanoparticles were prepared by controlled co-precipitation of Fe2+ and Fe3+ cations in ammonia at room temperature. Subsequently, the prepared Fe3O4 nanoparticles were coated with polyethyleneimine (PEI). The prepared materials were characterized by high-resolution transmission electron microscopy, X-ray diffraction, magnetometry, and zeta potential measurements. The prepared nanomaterials were used for magnetic harvesting of microalgae. The highest harvesting efficiencies were found for PEI-coated Fe3O4. The efficiency was pH-dependent. Higher harvesting efficiencies, up to 99%, were obtained in acidic solutions. The results show that magnetic harvesting can be significantly enhanced by PEI coating, as it increases the positive electrical charge of the nanoparticles. Most importantly, the flocculants can be prepared at room temperature, thereby reducing the production costs.

GC-MS profiling, anti-oxidant and anti-diabetic assessments of extracts from microalgae Scenedesmus falcatus (KU.B1) and Chlorella sorokiniana (KU.B2)

Microalgae are a potentially valuable source in the food, pharmaceutical and nutraceutical sectors. While biological activities surveys have investigated the pharmaceutical properties of a few microalgae species, there are not many reports covering biological activity studies. This study was carried out to identify the metabolites by gas chromatography-mass spectrometry and evaluate the anti-oxidant, anti-diabetic properties of green algae extracts, Chlorella sorokiniana (KU.B2) and Scenedesmus falcatus (KU.B1). A total of 51 different chemical constituents were detected and tentatively identified. The primary compounds in both microalgae extracts included (R)-2-hexanol (38.67% in C. sorokiniana and 23.53% in S. falcatus), n-hexadecanoic acid (13.58% in C. sorokiniana and 18.94% in S. falcatus) and octadecanoic acid (22.30% in C. sorokiniana and 32.67% in S. falcatus). According to the profiling results, the C. sorokiniana extract exhibited greater anti-oxidant activity, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging (IC50 = 480.30 ±?14.85 µg ml-1), nitric oxide (NO) radical scavenging (562.73 ±?3.52 µg mL-1) and ferric reducing anti-oxidant power (FRAP) of 58.51 ± 2.42 mgTE g-1. Comparatively, the C. sorokiniana extract had higher contents of alpha-glucosidase and alpha-amylase (IC50 = 491.22 ± 78.41 and 2,817.00 ±143.04 µg mL-1, respectively) than the S. falcatus extract. This first report demonstrated anti-diabetic effect of both extracts on diabetic enzymes. The results confirm microalgae's anti-oxidant and anti-diabetic properties and suggest their potential benefits in cosmeceutical, nutraceutical and pharmaceutical applications.

Cultivation of Microalgae in Unsterile Malting Effluent for Biomass Production and Lipid Productivity Improvement

Microalgae have the potential to grow in nutrient-rich environments and have the ability to accumulate nutrients from wastewater. The nutrients in malting wastewater are ideal for microalgae cultivation. However, there is limited published work on the growth characteristics of freshwater microalgae grown in malting effluent. This study examined the potential of diluted malting effluent for the growth of freshwater green algae Chlorella sp. and Chlamydomonas sp. isolated from northern Ontario and subsequent biomass and lipid production. Under the 18:6 h light/dark cultivation cycle, the highest cell number counted (540 × 104 cell·mL−1 on day 20) and total chlorophyll content were found in 50% diluted malting effluents for Chlorella sp., whereas the 70% dilution concentration was the most productive for Chlamydomonas (386 × 104 cell·mL−1 on day 16). The total lipid content was higher in the 50% dilution concentration of malting effluent in both Chlorella sp. (maximum 20.5%–minimum 11.5% of dry weight) and Chlamydomonas sp. (max 39.3%–min 25.9% of dry weight). These results emphasize the suitability of using unsterile diluted malting effluent for microalgae cultivation.

The Joint Toxicity of Organic Three-dimensional Layered Double Hydroxide and Methyl Orange to Green Algae Chlorella Vulgaris.

Organic modified layered double hydroxides (O-LDHs), known as attractive adsorbents for organic pollutants, may pose severe toxicity to the aquatic organisms during their large-scale application. However, little information is available on the toxicity of O-LDHs and the joint toxicity with the coexisted organic pollutants. Herein, we employed organic three-dimensional layered double hydroxide (O3D-LDH) and methyl orange (MO) as representative to investigate the toxicity mechanisms of single substance and its binary mixture on green algae Chlorella vulgaris. Results showed that O3D-LDH and MO presented concentration-dependent toxicity, the binary mixture showed additive effect after exposed to low O3D-LDH concentration (≤ 50mg/L), but antagonism was observed for the other. It revealed that the agglomeration of O3D-LDH and microalgae influenced chlorophyll content, eventually inhibiting the growth of algae. Overall, this toxicity investigation was critical for understanding the environmental risk of organic LDHs to provide theorical guidance for their practical application in the water purification.

Stimulatory and inhibitory effects of phenanthrene on physiological performance of Chlorella vulgaris and Skeletonema costatum

The effects of polycyclic aromatic hydrocarbons on phytoplankton have been extensively documented, but there is limited knowledge about the physiological responses of marine primary producers to phenanthrene at environmentally relevant levels. Here, we investigated the toxicity of phenanthrene (0, 1, and 5 or 10 μg L−1) to the physiological performance of two cosmopolitan phytoplankton species: the green alga Chlorella vulgaris and bloom-forming diatom Skeletonema costatum. The specific growth rates of both species were remarkably inhibited at both low (1 μg L−1) and high phenanthrene concentrations (5 or 10 μg L−1), while their tolerance to phenanthrene differed. At the highest phenanthrene concentration (10 μg L−1), the growth of C. vulgaris was inhibited by 69%, and no growth was observed for S. costatum cells. The superoxide dismutase activity of both species was enhanced at high phenanthrene concentration, and increased activity of catalase was only observed at high phenanthrene concentration in C. vulgaris. Interestingly, the low phenanthrene concentration stimulated the photosynthetic and relative electron transport rates of S. costatum, whereas hormetic effects were not found for growth. Based on our results, phenanthrene could be detrimental to these two species at a environmentally relevant level, while different tolerance levels were detected.

Mechanisms for establishing primary and secondary endosymbiosis in Paramecium.

Primary (eukaryote and procaryote) and secondary (eukaryote and eukaryote) endosymbioses are driving forces in eukaryotic cell evolution. These phenomena are still contributing to acquire new cell structures and functions. To understand mechanisms for establishment of each endosymbiosis, experiments that can induce endosymbiosis synchronously by mixing symbionts isolated from symbiont-bearing host cells and symbiont-free host cells are indispensable. Recent progress on endosymbiosis using Paramecium and their endonuclear symbiotic bacteria Holospora or symbiotic green alga Chlorella has been remarkable, providing excellent opportunities for elucidating host-symbiont interactions. These organisms are now becoming model organisms to know the mechanisms for establishing primary and secondary endosymbioses. Based on experiments of many researchers, we introduce how these endosymbionts escape from the host lysosomal fusion, how they migrate in the host cytoplasm to localize specific locations within the host, how their species specificity and strain specificity of the host cells are controlled, how their life cycles are controlled, how they escape from the host cell to infect more young host cell, how they affect the host viability and gene expression, what kind of substances are needed in these phenomena, and what changes had been induced in the symbiont and the host genomes.

Isolation and Identification of a Large Green Alga Virus (Chlorella Virus XW01) of Mimiviridae and Its Virophage (Chlorella Virus Virophage SW01) by Using Unicellular Green Algal Cultures.

Virophages are a group of small double-stranded DNA viruses that infect protist hosts and parasitize the viral factory of host giant/large viruses to propagate. Here, we discover a novel cell-virus-virophage (CVv) tripartite interaction system by using unicellular micro-green algae (Chlorella sp.) as eukaryotic hosts for the first time. Viral particles, resembling known virophages and large alga viruses, are detected in culture supernatants and inside algal cells. Complete genomic sequences of the virophage (Chlorella virus virophage SW01 [CVv-SW01]; 24,744 bp) and large virus (Chlorella virus XW01 [CV-XW01]; 407,612 bp) are obtained from the cocultures. Both genomic and phylogenetic analyses show that CVv-SW01 is closely related to virophages previously found in Dishui Lake. CV-XW01 shares the greatest number of homologous genes (n = 82) with Cafeteria roenbergensis virus (CroV) and phylogenetically represents the closest relative to CroV. This is the first report of a large green alga virus being affiliated with a heterotrophic zooplankton-infecting Cafeteriavirus of the family Mimiviridae. Moreover, the codon usage preferences of CV-XW01 and CVv-SW01 are highly similar to those of CroV and its virophage Mavirus, respectively. The discovery of such a novel CVv system with the green alga Chlorella sp. as the single cellular eukaryotic host paves a way to further investigate the potential interaction mechanism of CVv and its significance in the ecology of green algae and the evolution of large/giant viruses and their parasitic viruses. IMPORTANCE Parasitic virophages are small unicellular eukaryotic dsDNA viruses that rely on the viral factories of coinfecting giant/large dsDNA viruses for propagation. Presently, the identified eukaryotic hosts of isolated virophages were restricted to a free-living amoeba, Acanthamoeba polyphaga, and a widespread marine heterotrophic flagellate, Cafeteria roenbergensis. In this study, we successfully discovered and identified a novel tripartite interaction system comprised of a micro-green alga (Chlorella sp.), Mimiviridae large green alga virus, and virophage at the coculture level, with Chlorella sp. as the eukaryotic host, based on combination analysis of infection, morphotype, genome, and phylogeny. The large green alga virus CV-XW01 represents the closest relative to the Mimiviridae giant virus Cafeteria roenbergensis virus, host virus of the virophage Mavirus, as well as a novel large virus of Mimiviridae that infects a non-protozoan protist host. The virophage CVv-SW01 highly resembles Mavirus in its codon usage frequency and preference, although they are phylogenetically distantly related. These findings give novel insights into the diversity of large/giant viruses and their virophages.

Isolation, identification, and optimization of growth conditions for the marine microalgae isolated from the Gulf of Mannar, South-east coast of India

Marine microalgae were isolated from the selected locations from the coastal waters of Gulf of Mannar during December 2019 to February 2021. A total of 16 microalgal species were collected and identified morphologically using a light microscope with image capture system. Of these, five pure isolates of three pennate diatoms viz., Cylindrotheca fusiformis, Amphora sp., and Navicula clavata, and two species of green algae (Nannochloropsis salina and Chlorella sp.) were identified morphologically by field-emission scanning electron microscopy (FE-SEM) and confirmed by PCR amplification sequence analysis of 18S rRNA. The isolates confirmed by PCR were C. fusiformis, Amphora sp., N. clavata, and N. salina whereas Chlorella sp., was confirmed through FE-SEM. Optimization of culture conditions for the identified microalgae was studied with different culture media (Diatom Artificial Medium (DAM), F/2 medium, and Walne’s medium) by various salinities to assess their best growth for commercial application. At 30 ppt salinity, the maximum cell density of C. fusiformis observed in DAM was 7.63 × 106 cells/mL, whereas Amphora sp. and N. clavata showed maximum cell density of 1.20 × 106 and 1.35 × 106 cells/mL, respectively, in F/2 medium. At 35 ppt salinity, maximum cell density of Chlorella sp. was 12.1 × 106 cells/mL in the F/2 medium. Similarly, the maximum growth of 13.7 × 106 cells/mL was obtained at 35 ppt salinity for N. salina in Walne’s medium. As the microalgal strains were isolated at succession stage, they can tolerate a wide range of environmental conditions and could be mass produced in outdoor conditions for industrial applications

Influence of Urea on Organic Bulk Fertilizer of Spent Coffee Grounds and Green Algae Chlorella sp. Biomass

To maintain high production and growing rates of plants, synthetically obtained fertilizers are commonly used. Excessive amounts of fertilizers damage the natural ecosystem and cause various environmental problems. In relation to the environment and its sustainability, another great environmental, economic, and social issue is food loss and waste. This paper aims to evaluate the impact of spent coffee grounds (SCG) on soil properties, rye growth, and their possibilities to be used as the biodegradable and organic material in the production of organic bulk fertilizer. This study demonstrated that spent coffee grounds contain primary nutrients; moreover, SCG could increase the content of soil organic matter. The addition of 4 wt% to 8 wt% SCG increased the number of spore-forming bacteria from &lt;103 colony forming units/g soil (CFU/g soil) to 3 × 104 CFU/g soil, along with nitrogen assimilating bacteria (plain soil resulted in 5.0 × 105 CFU/g, and addition of SCG increased the value to 5.0 × 107 CFU/g). Since spent coffee grounds have a relatively high porosity and absorbance (25.3 ± 3.4 wt% in a water vapor environment and 4.0 ± 0.6 wt% in the environment of saturated sodium nitrate solution), they could be used to reduce the amount of water required for irrigation. To fully exploit their nutritional value for plants, spent coffee grounds were mixed with green algae biomass along with urea, and, during the research, higher value products (organic bulk fertilizer) were obtained.