Microalga Chlorella Vulgaris Research Articles

Adsorption mechanism of trace heavy metals on microplastics and simulating their effect on microalgae in river

Microplastics (MPs) and heavy-metal contamination in freshwater is an increasing concern. Fe, Mn, Pb, Zn, Cr, and Cd are common heavy metals that can easily flow into rivers causing water pollution. Microplastics act as carriers for heavy metals and increase the transport of contaminants in freshwater systems. We investigated the adsorption mechanisms of three kinds of MPs having similar particle sizes, namely polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC), with respect to trace heavy metals of Pb, Cu, Cr, and Cd under different temperature and salinity conditions. The reaction kinetics of the adsorption of different trace heavy metals on different MPs were consistent with both the quasi primary and quasi secondary kinetic models, indicating the complexity of heavy metal adsorption by MPs. The adsorption rate of heavy metal on MPs was mainly controlled by intra-particle diffusion, and the isotherm model indicated that the adsorption of Pb, Cu, Cr, and Cd by MPs occurred in the form of monolayer physical adsorption. Additionally, an increase in temperature and decrease in salinity were favourable to improve the affinity of MPs toward heavy metals (through adsorption). Zeta potential measurements and Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses indicated that electrostatic force interaction was the main mechanism of the adsorption process; oxygen-containing functional groups, π-π interaction, and halogen bonds played important roles in the process of adsorption. Furthermore, the growth inhibition and oxidative stress of microalgae Chlorella vulgaris (GY-D27) due to PP, PS, and PVC were analysed; notably, MPs or Pb inhibited the growth of Chlorella vulgaris. However, the reduced toxicity to Chlorella vulgaris, with respect to a mixture of Pb and MPs, was confirmed using superoxide dismutase and catalase enzyme activities. Our results can be applied for the risk assessment of heavy metals and MPs in aquatic environments.

Replacing the Concentrate Feed Mixture with Moringa oleifera Leaves Silage and Chlorella vulgaris Microalgae Mixture in Diets of Damascus Goats: Lactation Performance, Nutrient Utilization, and Ruminal Fermentation.

Simple SummaryMoringa oleifera and Chlorella vulgaris microalgae have a good balance of amino acids with high protein contents; however, complementary and synergic effects between proteins can improve their nutritive value compared to the individual additive. Replacing a concentrate mixture at 20% to 40% levels with a mixture of M. oleifera and microalgae improved nutrient digestibility, ruminal fermentation characteristics, milk production, composition and the fatty acid profile of goats. Inclusion of M. oleifera and microalgae mixture to partially replace concentrates may enhance milk production performance and milk quality without affecting animal health.Exploring suitable alternatives for high-cost concentrate feeds is a critical factor for successful livestock production. The present experiment aimed to evaluate the dietary inclusion of Moringa oleifera silage and Chlorella vulgaris microalgae (at 1% of total diet, DM basis) in a quintuplicate 3 × 3 Latin square design for milk production performance, nutrient utilization and ruminal fermentation in Damascus goats. Fifteen lactating Damascus goats were divided into three groups to be fed a diet composed of a concentrate mixture and rice straw at 60:40 (DM basis) in the control group and fed for 30 days in each period. The concentrate mixture in the control treatment was replaced with M. oleifera silage and C. vulgaris microalgae at 20% (MA20 treatment) or 40% (MA40 treatment). Treatments did not affect total feed intake but increased (p < 0.01) crude protein (CP) and fiber intakes while decreasing nonstructural carbohydrates intake. The digestibility of CP and acid detergent fiber increased due to silage supplementation compared to the control treatment. Treatments increased (p < 0.05) ruminal pH and the concentrations of total volatile fatty acids, acetate, and propionate; however, they decreased (p < 0.05) the concentrations of ammonia-N. Treatments increased (p < 0.05) the concentrations of serum glucose and antioxidant capacity. Both MA20 and MA40 treatments increased the daily milk production, the concentrations of milk fat and lactose, and feed efficiency compared to the control treatment. Additionally, MA20 and MA40 treatments increased the proportions of total polyunsaturated fatty acids and total conjugated linoleic acids. It is concluded that the concentrate feed mixture in the diet of lactating goats can be replaced up to 40% (equals to 24% of total diet) with M. oleifera silage to improve feed intake and nutrient utilization, and milk production performance.

Comparison of biodiesel production from Dunaliella salina teodor and Chlorella vulgaris microalgae using supercritical fluid technique

Extraction of oil to produce biofuels from Chlorella vulgaris and Dunaliella salina teodor were investigated by supercritical CO2 solution. This study was studied in 8 treatments (salinity, acidity, nutrients) under light and dark conditions for both microalgae. According to the results obtained regarding growth factors, the highest amount of the specific growth rate (SGR), production biomass and CO2 consumption rate were higher in Chlorella vulgaris microalgae. The number of microalgae cells and the pH value at the end of growth period were higher in Chlorella vulgaris microalgae. The results obtained for approximate compositions showed that the amount of fat in Chlorella vulgaris microalgae with salinity shock in the dark conditions was the highest and the lowest value in the treatment of acid shock and salinity in light irradiated conditions in Dunaliella salina teodor. The amount of saturated fatty acids in Chlorella vulgaris microalgae was generally higher than that of Dunaliella salina teodor.

Evaluation of fatty acid profiles of Chlorella Vulgaris microalgae grown in dairy wastewater for producing biofuel.

Biodiesel is a biofuel made from plant oils and animal lipids. Utilization of lipid accumulation in algae biomass as biodiesel is a good alternative to fossil fuels. In this research Chlorella vulgaris microalga was applied after planting in BG11 culture medium in effluent and wastewater of dairy industry after preparation of 25, 50, and 75% dilutions. Algae in two concentrations with low (13 million cells/mL) and high density (26 million cells/mL) were injected. According to the results obtained in the wastewater environment the highest amount of C16:0 fatty acid was observed in F2 25% treatment, and C18:0 fatty acid is related to F1 75% treatment. In the effluent environment, the highest amount of fatty acids C16:0 and C16:1n7 occur in P1 50% treatment, and C18:0 and C18:3n3 fatty acids are related to P1 50% treatment, respectively. The highest amount of saturated fatty acids (SFA) was reported at P2 75% treatment (56.25%) and monounsaturated fatty acids (MUFA) has accumulated in F175% (40.13%) treatment. Chlorella vulgaris microalgae can be considered as a rich source of lipid and fatty acid profiles in both wastewater and effluents, and it can be regarded as potential significance source for biodiesel production.

Integrated CO2 Capture and Nutrient Removal by Microalgae Chlorella vulgaris and Optimization Using Neural Network and Support Vector Regression

Integrated CO2 Capture and Nutrient Removal by Microalgae Chlorella vulgaris and Optimization Using Neural Network and Support Vector Regression

High rate algal systems for treating wastewater: A comparison

Algal systems can remove nitrogen (N) and phosphorus (P) from wastewater while producing valuable biomass. The microalga Chlorella vulgaris in three concentrated forms (suspended, entrapped in Ca-alginate gel beads and as a biofilm on supports and the macroalga Oedogonium cardiacum were compared for treating secondary effluent containing 15 mg/L of ammonium (N-NH4+), 6 mg/L of nitrate (N-NO3−), and 7 mg/L of total phosphorus (TP) with a hydraulic retention time of 12 h. Identical conditions and reaction vessels enabled a direct comparison of growth systems. The biofilm system was the most effective of the microalgal systems, decreasing concentrations to 1.9 mg/L TP and 0.5 mg/L N-NO3− on average from day 3 to 24, and like the other microalgal systems, was not as effective for N-NH4+ removal (average of 9.0 mg/L). The macroalgal system decreased TP to 1.3 mg/L and N-NH4+ to ≤0.5 mg/L on average from day 16 to 30 and operated for longer than the other systems, but was not effective for N-NO3− removal (average of 4.8 mg/L). Hence the minimum TN concentration of the effluent from the macroalgal system (7.1 mg/L) was lower than for the biofilm system (10.6 mg/L) from the feed of 24 mg/L. The biofilm system produced 56 mg/L/d and the macroalgae 102 mg/L/d of biomass. The production of the highest quality effluent for longer and of more biomass than the microalgal systems, combined with their larger cell size which facilitates reactor operation, demonstrates that macroalgae can compete with microalgae for wastewater remediation.

Immobilization Method to Separate Microalgae Biomass for Fatty Acid Methyl Ester Production

AbstractAn immobilization method for simplified separation of cultured cells and their products from the growth media was developed. The growth rates of both immobilized and free cells of the microalga Chlorella vulgaris were compared. The free and immobilized cells reached nearly identical cell densities. The reported immobilization strategy uses a combination of matrices (sodium alginate (SA), calcium alginate (CA), and sodium carboxymethyl cellulose (CMC)) at different matrix/microalgae volumetric ratios of 0.3:1 and 1:1. The microalgae in the SACACMC/Mc (0.3:1) beads achieved the highest cell density. The cells immobilized in SACACMC/Mc (0.3:1) gave the highest lipid yield, as compared to the cells immobilized in SA. Pore size and membrane thickness analysis as well as surface images of SACACMC/Mc (0.3:1) showed that the mixed matrix had a unique structure favoring lipid production.

Production of Biodiesel from Mixed Castor Seed and Microalgae Oils: Optimization of the Production and Fuel Quality Assessment

The diminishing reserves and environmental consequences of the fossil fuel-based petrodiesel necessitate the exploration of an alternative fuel with better quality and minimum environmental impacts. The study explores the optimization of biodiesel production from nonfood and locally available mixed feedstocks as an effective and a sustainable approach to solve the insufficiency and high costs of single oil feedstock. The selection of suitable oil feedstocks and optimization of process variables are the prime issues for cost-effective industrial scale production of biodiesel from mixed feedstocks toward the industrial scale production of biodiesel. The objective of this study was to optimize process variables for the alkaline transesterification of mixed castor seed and microalgae oils to optimize the yield of biodiesel. Oils were extracted from dried microalgae (Chlorella vulgaris) biomass and castor seed kernel using methanol. The oils were purified, characterized, mixed in a 1 : 1 ratio, and converted to biodiesel. The transesterification experiments designed according to the central composite design (CCD) were used to optimize the yield of biodiesel through the response surface methodology (RSM). Experimental results were analyzed by response surface regression to produce a model for predicting biodiesel yield. Model significance, fitness, the effect of significant variables, and interactions between the variables on the yield of biodiesel were studied through the analysis of variance (ANOVA). The optimization of transesterification process variables revealed that the catalyst concentration of 1.23% (w/w), ethanol to mixed oil ratio of 5.94 : 1 (v/v), and reaction temperature of 51.0°C were the optimum conditions to achieve an optimum biodiesel yield of 92.88%. Validation experiments conducted under the optimum conditions resulted in the biodiesel yield of 92.36%, which is very close to the model predicted value. Various standard methods were used to characterize the biodiesel produced under optimum conditions, and it was found compatible with ASTM 751 and EN14214 biodiesel standards.

The Fouling Effect on Commercial Ceramic Membranes during Filtration of Microalgae Chlorella vulgaris and Monoraphidium contortum

Although interest in the use of membranes for the concentration of microalgal biomass has steadily been growing, little is known regarding the phenomena of membrane fouling. In addition, more attention has been given to polymeric membranes compared to ceramic membranes, which have a longer life that is associated with a higher resistance to aggressive chemical cleaning. In this study, microfiltration (MF) and ultrafiltration (UF) of two microalgae species, Chlorella vulgaris and Monoraphidium contortum, were carried out using tubular crossflow ceramic membranes. Permeate flux was measured, resistance was calculated, and dissolved organic carbon (DOC) was determined. The flux reduction during the first 10 min of filtration was higher for MF than UF (&gt;70% and &lt;50%), and steady-state permeate fluxes were &lt;5% (for MF) and &lt;25% (for UF) of initial (in m3 m−2 s−1) 6.2 × 10−4 (for MF) and 1.7 × 10−4 (for UF). Total resistances (in m−1) were in the ranges of 4.2–5.4 × 1012 (UF) and 2.6–3.1 × 1012 (MF) for M. contortum and C. vulgaris, respectively. DOC reduction was higher for UF membrane (&gt;80%) than for MF (&lt;66%) and DOC concentrations (mg C L−1) in permeates following MF and UF were about five and two, respectively. In conclusion, we demonstrated: (i) higher irreversible resistance for UF and reversible resistance for MF; (ii) permeate flux higher for UF and for M. contortum; (iii) the significant role of dissolved organic compounds in the formation of reversible resistance for MF and irreversible resistance for UF.

Theoretical study of flue gas CO2 conversion to microalgae Chlorella vulgaris biomass in a bubble column photobioreactor: Tanks-in-series approach, kinetic modeling, and dynamic optimization

The current theoretical research is focused on using flue gas CO2 as carbon source to cultivate the microalgae Chlorella vulgaris in a bubble column photobioreactor. The tanks-in-series approach is used to model this semi-batch process. A kinetic model is deployed taking account of light irradiance as well as dissolved CO2 and inorganic nitrogen concentrations in the liquid phase. Model parameters are evaluated based on the experimental data reported in the literature. The developed model allows for detailed evaluation of concentration variations of key components along the photobioreactor over the whole process time. Using this method, variables can be distinguished and categorized into two groups: those with considerable spatial distributions and those that are assumed to be lumped and volume-averaged under certain conditions. Simulation results demonstrate a considerable aqueous CO2 concentration gradient along the photobioreactor for moderate liquid backflows unlike biomass and dissolved inorganic nitrogen. After performing sensitivity analysis, a multi-objective optimization problem is formulated and solved using parallelized differential evolution to enhance carbon capture rate and biomass productivity. The proposed approach for modeling and optimization improves the carbon capture rate with a reasonable biomass productivity. This method paves the way for developing more efficient and sophisticated bioprocess design procedures.

Processing wet microalgae for direct biodiesel production: optimization of the two-stage process assisted by radio frequency heating

ABSTRACT A two-stage biodiesel production directly from wet microalgae (Chlorella vulgaris) assisted by radio frequency (RF) heating was optimized in this study with the response surface methodology (RSM) applied to both two steps. In order to apply RSM to the two stages rather than to a one-step reaction, a three-variable, five-level central composite design (CCD) was employed to evaluate the effects of three key parameters, i.e. HCl to MeOH ratio (v/v), MeOH volume, and RF heating time. Two regression equations (one regression equation for each stage) were obtained, and two sets of optimized production conditions with a slight difference were also determined. The best predicted FAME yield of 93.1% was obtained at a HCl to MeOH ratio of 4.27 (v/v), a MeOH volume of 28.5 mL, and a RF heating time of 19.2 min. Although the second stage of conversion increased the FAME yield from 82.9% to 93.1%, this process would cause additional consumption of time, solvent, and energy. Verification experiments were carried out at the optimized point and resulted in a yield of 92.7 ± 0.1%, which validated the reliability of the prediction model. All processing steps, including cell destruction, esterification, and transesterification, were carried out at temperatures below 100°C and atmospheric pressure. Therefore, no pressure-proof nor high-temperature apparatus was required. The procedure shows great potential for industrial application because of its high FAME yield, simple operation, low chemical consumption, and short processing time. The principles of the procedure can also be applied to other microalgae with high lipid contents.

Eco-technological method for carbon dioxide biosorption and molecular mechanism of the RuBisCO enzyme from unicellular microalga Chlorella vulgaris RDS03: a synergistic approach

Eco-technological method for carbon dioxide biosorption and molecular mechanism of the RuBisCO enzyme from unicellular microalga Chlorella vulgaris RDS03: a synergistic approach

Continuous antibiotic attenuation in algal membrane photobioreactor: Performance and kinetics

The attenuation of 10 mixed antibiotics along with nutrients in a continuous flow mode by four freshwater microalgae (Haematococcus pluvialis, Selenastrum capricornutum, Scenedesmus quadricauda, and Chlorella vulgaris) was examined in membrane photobioreactors (MPBRs). At lab-scale, consistent removal of both antibiotic and nutrient was shown by H. pluvialis and S. quadricauda, respectively. The system exhibited better performance with enhanced removal at HRT 24 h compared to 12 h and 48 h. The highest removal efficiency of antibiotics was observed in H. pluvialis MPBR, with the mean antibiotic removal values of 53.57%− 96.33%. Biodegradation was the major removal pathway of the antibiotics in the algal-MPBR (AMPBR), while removal by bioadsorption, bioaccumulation, membrane rejection, and abiotic was minor. Then, the bacterial feature was studied and showed significant influence from system hydrodynamics. The kinetics of continuous flow antibiotic removal followed Stover-Kincannon and Grau second-order models, which revealed great potential of AMPBR to withstand antibiotic load. The latter coupled with the computational fluid dynamic simulation was successfully applied for the residual antibiotic prediction and potential system optimization. Overall, these results provide an important reference for continuous flow antibiotic removal using AMPBR.

Design and fabrication of box-type passive solar dryer (BTPSD) with thermal insulation material for valorizing biomass and neutral lipids of marine Chlorella vulgaris for biodiesel application

The staggering rate of population growth has augmented the reliance on fossil fuel utilization, and it kindled the society to explore alternative and sustainable sources of energy. In this regard, biodiesel from microalgae came to the limelight; but crucial energy-consuming and expensive processes like cultivation, harvesting, and drying make the microalgal biodiesel unsustainable and economically unfeasible. To surpass these impediments, in this research work, a low-cost box-type passive solar dryer (BTPSD) is designed and fabricated with zero energy consumption mode and compared with conventional hot air oven for drying the biomass, neutral lipids of the marine microalga Chlorella vulgaris for biodiesel application. The onset of the work, BTPSD with 2 cm thickness of glass wool as TIM (thermal insulation material), 4 cm TIM thickness and no TIM was simulated for thermal storage behaviour using ANSYS FLUENT 19.2 Computational Fluid Dynamics tool and based on the results, 4 cm TIM thickness was chosen for experimentation. The time taken by BTPSD and hot air oven to remove the moisture from algal biomass is 3 and 2 h, respectively, whereas for neutral lipids drying, it was 4 and 3.5 h, respectively. Though there is a little difference in drying time, neutral lipid and FAME content from both drying systems are tantamount, i.e., ~ 12% neutral lipid and 95% FAME. Further, the percentage of vital fatty acids identified from BTPSD and hot air oven methods are almost similar, i.e., C16:0 (23.4%), C18:1 (14.3%), C18:3 (11.42%), C18:1 (9.22%). Though the time taken for valorizing biomass and neutral lipids of C. vulgaris by BTPSD is slightly longer than hot air oven, low energy consumption and cost-effectiveness make the BTPSD a promising system to scale down the microalgal biodiesel production cost significantly.

Clay 3D printing as a bio-design research tool: development of photosynthetic living building components

Within architecture, microalgae are employed to address sustainability issues and mitigate the impacts of anthropogenic carbon dioxide (CO2) emissions. This study proposes digital fabrication of ceramic ‘living’ building components as an investigative tool for design conditions. The health of the chlorophyte (green) microalga Chlorella vulgaris was monitored over two-week periods when immobilized in kappa carrageenan and clay binder-based hydrogels, and grown on a range of digitally fabricated ceramic components. The use of 3D printing is presented in relation to laboratory testing of controlled substrate variables including the impact of ceramic firing temperature, component wall thickness, three types of geometry for exploring cell growth, surface patterns to investigate cell migration, internal chamber subdivisions and clay type. The experiments reveal the benefits and limitations of creating micro-ecologies for algae growth through the introduction of geometry variation. In this study, the natural organismal sensing abilities are explored as a means for cell distribution.

Synthesis and evaluation of cationic polyacrylamide and polyacrylate flocculants for harvesting freshwater and marine microalgae

• Cationic PAETAC & PAmPTAC were synthesized by UV-induced radical polymerization. • New polymers showed good flocculation performance of freshwater & marine microalgae. • Optimal doses of PAETAC were 50 and 4.8 mg/g for C. vulgaris & P. purpureum. • PAETAC and PAmPTAC produced stable flocs, supporting simple dewatering step. This study addresses the challenge of microalgae harvesting through the development of flocculants. Two positively charged cationic polymers including poly[2 (acryloyloxy)ethyl]trimethylammonium chloride (PAETAC) and poly(3 acrylamidopropyl)trimethylammonium chloride (PAmPTAC) were synthesized using the UV-induced radical polymerization, for harvesting both freshwater and marine microalgae. The results show that the synthesized polymers have excellent flocculation performance for both freshwater green microalgae ( Chlorella vulgaris) and marine red microalgae ( Porphyridium purpureum). PAETAC outperformed PAmPTAC for both Chlorella vulgaris and Porphyridium purpureum microalgae. The optimal PAETAC doses for Chlorella vulgaris and Porphyridium purpureum microalgae were 50 and 4.8 mg/g of dry biomass while the optimal PAmPTAC doses were 252 and 35 mg/g of dry biomass respectively. Additionally, the floc formation with the PAETAC was more stable than PAmPTAC, which supported the dewatering step via sieving. The superior performance can be attributed to the higher molecular weight of the PAETAC polymer when compared to the PAmPTAC polymer. In comparison to commercially available polydiallyldimethylammonium chloride (PolyDADMAC), the newly synthesised PAETAC and PAmPTAC polymers demonstrated superior flocculation efficiency at a lower dose. The findings of this study established a platform technology for designing and synthesising cationic flocculants for use in microalgae harvesting.

Nano-sized polystyrene plastics toxicity to microalgae Chlorella vulgaris: Toxicity mitigation using humic acid.

Polystyrene nanoplastics (PS-NPs) can cause toxicity in aquatic organisms, but presence of natural organic matter (NOM) may alter toxicity of PS-NPs. To better understand effects of NOM on acute toxicity of PS-NPs, humic acid (HA) as a model of NOM was added to green microalga Chlorella vulgaris medium in the presence of amino-functionalized polystyrene nanoplastics (PS-NH2). Acute toxicity tests of PS-NH2 to C. vulgaris biomass and chlorophyll a content showed statistical differences between media treated with different concentrations of PS-NH2 and control groups (p<0.05). HA significantly mitigated PS-NH2 toxicity to C. vulgaris biomass and chlorophyll a end-points (p<0.05). Additionally, high HA concentration was more effective than low concentration (10 vs 5 mg/L), showing a greater ameliorative effect on PS-NH2 acute toxicity (p<0.05). Algae exposed to higher PS-NH2 concentrations showed greater morphological changes (i.e., diminution of photosynthetic pigments, reduction of algal size and formation of more cellular aggregates). Formation of high amounts of algal aggregates under influence of PS-NH2 was presumably related to the high electrostatic tendency of these particles (with positively charged surfaces) to C. vulgaris polysaccharide walls (having negative charge). Formation of aggregates was significantly reduced in the presence of HA. HA with dominant negatively charged functional groups (following sorption by PS-NH2 via reduction of PS-NH2 zeta potential), could decrease electrostatic attraction between PS-NH2 and algae, thereby substantially ameliorating cellular aggregation and cell size reduction.

Study on synergistic mechanism of Co-hydrothermal liquefaction of microalgae and macroalgae

The mechanism of Co-hydrothermal liquefaction (Co-HTL) between microalgae (Chlorella vulgaris) and macroalgae (Enteromorpha clathrata) was studied, and the effects of different mass ratios of microalgae and macroalgae on the yield of Co-HTL products and the distribution of nitrogen-contained compounds were discussed. The study found that Co-HTL has a positive effect on the increase of bio-oil yield, with a maximum increase of 15.0 wt%. The ultimate analysis, FTIR, GC-MS and other means were carried out to investigate the composition liquefied oil products. Compared with the bio-oil obtained from Enteromorpha, the nitrogen compounds content of amides in the bio-oil prepared by mixed sample increased significantly, and maximum yield increased from 0.9% to 13.6%, while pyrazine and piperazine significantly decreased by 5.1% and 11.0%, respectively. This could be due to the intensification of the amidation reaction in the Co-HTL, and consequently interfering with the Maillard pathway. Except for at the ratio of 1/1, the content of nitrogen compounds in the oil phase at all ratios was lower than the theoretical value. At the ratio of 3/1, the content of nitrogen compounds decreased the most compared with the theoretical value, which is reduced by 7.5%, and the content was 41.0%. When the mixing ratio was 1/3, the nitrogen content of aqueous phase was the highest (85.7%), and the total nitrogen content in aqueous phase was 2669.2 mg/L.

Efficacy of Ciprofloxacin and Amoxicillin Removal and the Effect on the Biochemical Composition of Chlorella vulgaris.

Antibiotics are frequently detected in the aquatic environment due to their excessive usage and low-efficiency removal in wastewater treatment plants. This can provide the origin to the development of antibiotic-resistant genes in the microbial community, with considerable ecotoxicity to the environment. Among the antibiotics, the occurrence of ciprofloxacin (CIP) and amoxicillin (AMX) has been detected in various water matrices at different concentrations around the Earth. They are designated as emerging contaminants (ECs). Microalga Chlorella vulgaris (C. vulgaris) has been extensively employed in phycoremediation studies for its acclimatization property, non-target organisms for antibiotics, and the production of value-added bioproducts utilizing the nutrients from the wastewater. In this study, C. vulgaris medium was spiked with 5 mg/L of CIP and AMX, and investigated for its growth-stimulating effects, antibiotic removal capabilities, and its effects on the biochemical composition of algal cells compared to the control medium for 7 days. The results demonstrated that C. vulgaris adapted the antibiotic spiked medium and removed CIP (37 ± 2%) and AMX (25 ± 3%), respectively. The operating mechanisms were bioadsorption, followed by bioaccumulation, and biodegradation, with an increase in cell density up to 46 ± 3% (CIP) and 36 ± 4% (AMX), compared to the control medium. Further investigations revealed that, in the CIP stress-induced algal medium, an increase in major photosynthetic pigment chlorophyll-a (30%) and biochemical composition (lipids (50%), carbohydrates (32%), and proteins (65%)) was observed, respectively, compared to the control medium. In the AMX stress-induced algal medium, increases in chlorophyll-a (22%), lipids (46%), carbohydrates (45%), and proteins (49%) production were observed compared to the control medium. Comparing the two different stress conditions and considering that CIP is more toxic than AMX, this study provided insights on the photosynthetic activity and biochemical composition of C. vulgaris during the stress conditions and the response of algae towards the specific antibiotic stress. The current study confirmed the ability of C. vulgaris to adapt, bioadsorb, bioaccumulate, and biodegrade emerging contaminants. Moreover, the results showed that C. vulgaris is not only able to remove CIP and AMX from the medium but also can increase the production of valuable biomass usable in the production of various bioproducts.

Obtaining Fat-Soluble Pigments—Carotenoids from the Biomass of Chlorella Microalgae

The aim of this study was to use a directed mode of cultivation of the microalgae Chlorella for biomass production, followed by the subsequent extraction of carotenoids. The effect of a stress inducer of carotenogenesis (hydrogen peroxide) and a growth stimulator (pyridoxine, vitamin B6) on the accumulation of photosynthetic pigments by the biomass of the microalga C. vulgarisBIN in the process of directed cultivation was studied. It was revealed that the combination of these additives in the culture medium increases the content of chlorophylls and carotenoids in the biomass twofold compared to the control sample. The preliminary activation of the biomass by high-speed ultra-homogenization (a rotor rotation range from 6000 to 12,000 rpm) was also investigated. Using ultrasound extraction, the pigment complex was isolated from the activated biomass. The saponification and subsequent neutralization of carotenoids were carried out in an inert medium. The resulting sample contained carotenoids in the amount of 52 ± 3 mg/mL. The chemical profile of the carotenoids in the biomass of the microalga Chlorella vulgaris BIN was also established. The major carotenoid was lutein (45%), followed by fucoxanthin (12%) and β-carotene (4.3%). The oil extract of the carotenoids may be used for the further production of a microencapsulated product with the aim of targeted delivery to the lower parts of the gastrointestinal tract.