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Karataş B. Effects of Chlorella sp. and Schizochytrium sp. extracts on growth indices, body composition, and gene expression profiles in rainbow trout (Oncorhynchus mykiss). Comp Biochem Physiol B Biochem Mol Biol 2025; 276:111047. [PMID: 39551361 DOI: 10.1016/j.cbpb.2024.111047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Revised: 11/07/2024] [Accepted: 11/12/2024] [Indexed: 11/19/2024]
Abstract
This study assessed the impact of dietary Chlorella sp. and Schizochytrium sp. extracts on growth performance, feed utilization, body composition, and gene expression related to growth, digestion, antioxidant defense, and immune response in rainbow trout (Oncorhynchus mykiss). A total of 180 fish (average weight 8.92 ± 0.04 g) were randomly distributed into 12 fiberglass tanks (400 L, 15 fish per tank, three replicates per treatment). Fish were divided into four dietary groups for 60 days: 0 % (Control), 0.5 % Chlorella sp. extract (CH), 0.5 % Schizochytrium sp. extract (SC), and a combined 0.25 % Chlorella sp. and 0.25 % Schizochytrium sp. (CH + SC). At trial end, fish in the CH + SC group had a final weight (FW) of 27.06 ± 0.28 g, significantly higher than other groups (P < 0.05), with improved growth parameters (P < 0.05). While body composition showed no differences in moisture, lipid, or ash content, crude protein was significantly higher in CH + SC (P < 0.05). Gene expression analysis showed upregulation of the growth hormone GH-I gene in the CH + SC group (P < 0.05). Genes related to digestive enzymes (trypsin, lipase, amylase) were also upregulated in all microalgae groups, with the highest levels in CH + SC (P < 0.05). Additionally, antioxidant genes (SOD, CAT, GPx) and immune-related genes (LYZII, TNF-α, IL-1β) showed elevated expression in CH + SC (P < 0.05). This study demonstrated that a diet containing Chlorella sp. and Schizochytrium sp. extracts supports growth, enhances nutrient utilization, and upregulates genes related to antioxidant and immune function in rainbow trout. Further research is recommended to assess functional immune responses and enzyme activities to confirm these physiological effects.
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Kodama Y, Fujishima M. Effects of the Symbiotic Chlorella variabilis on the Host Ciliate Paramecium bursaria Phenotypes. Microorganisms 2024; 12:2537. [PMID: 39770740 PMCID: PMC11678095 DOI: 10.3390/microorganisms12122537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2024] [Revised: 12/04/2024] [Accepted: 12/07/2024] [Indexed: 01/11/2025] Open
Abstract
Paramecium bursaria, a ciliated protist, forms a symbiotic relationship with the green alga Chlorella variabilis. This endosymbiotic association is a model system for studying the establishment of secondary symbiosis and interactions between the symbiont and its host organisms. Symbiotic algae reside in specialized compartments called perialgal vacuoles (PVs) within the host cytoplasm, which protect them from digestion by host lysosomal fusion. The relationship between P. bursaria and symbiotic Chlorella spp. is characterized by mutualism, in which both organisms benefit from this association. Furthermore, symbiotic algae also influence their host phenotypes, and algae-free P. bursaria can be obtained through various methods and reassociated with symbiotic algae, making it a valuable tool for studying secondary endosymbiosis. Recent advancements in genomic and transcriptomic studies on both hosts and symbionts have further enhanced the utility of this model system. This review summarizes the infection process of the symbiotic alga C. variabilis and its effects on the algal infection on number of host trichocysts, mitochondria, cytoplasmic crystals, total protein amount, stress responses, photoaccumulation, and circadian rhythms of the host P. bursaria.
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Daniela Rios Ramirez K, Botero Ñañez K, Leonardo Gonzalez Gomez C, Thiago Andrade Moreira Í. Efficient PAHs removal and CO 2 fixation by marine microalgae in wastewater using an airlift photobioreactor for biofuel production. ENVIRONMENTAL RESEARCH 2024; 261:119672. [PMID: 39053760 DOI: 10.1016/j.envres.2024.119672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Revised: 06/05/2024] [Accepted: 07/22/2024] [Indexed: 07/27/2024]
Abstract
Microalgae cultures have emerged as a promising strategy in diverse areas, ranging from wastewater treatment to biofuel production, thus contributing to the search for carbon neutrality. These photosynthetic organisms can utilize the resources present in wastewater and fix atmospheric CO2 to produce biomass with high energy potential. In this study, the removal efficiency of Polycyclic Aromatic Hydrocarbons (PAHs), CO2 fixation and lipid content in the biomass produced from microalgae grown in airlift photobioreactor were evaluated. Four mesoscale cultures were carried out: Control (Seawater + Conway medium), Treatment A (Oil Produced Water + Poultry Effluent Water), Treatment B (Poultry Effluent Water + Seawater) and Treatment C (Oil Produced Water, Seawater and nutrients). The impact of biostimulation, through the addition of nutrients, on PAHs removal efficiency (up to 90%), CO2 fixation rate (up to 0.20 g L-1 d-1) and the composition of the generated biomass was observed. Primarily, the addition of nitrates to the culture medium impacted CO2 fixation rate of the microalgae. In addition, a direct correlation was observed between PAHs removal and lipid accumulation in the biomass, up to 36% in dry weight, demonstrating microalgae's ability to take advantage of the organic carbon (PAHs) present in the culture medium to generate lipid-rich biomass. The concentration of polysaccharides in the biomass obtained did not exceed 12% on a dry weight basis, and the Higher Heating Value (HHV) ranged between 17 and 21 MJ kg-1. Finally, the potential of generating hydrogen through pyrolysis was highlighted, taking advantage of the characteristics of biomass as a conversion route to produce biofuels. These results show that microalgae are effective in wastewater treatment and have great potential in producing biofuels, thus contributing to the transition towards more sustainable energy sources and climate change mitigation.
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Cui X, Yang N, Cui H, Yang Q, Wu Z, Shao B, Zhao Y, Tong Y. Interspecific competition enhances microcystin production by Microcystis aeruginosa under the interactive influences of temperature and nutrients. WATER RESEARCH 2024; 265:122308. [PMID: 39180952 DOI: 10.1016/j.watres.2024.122308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2024] [Revised: 08/14/2024] [Accepted: 08/20/2024] [Indexed: 08/27/2024]
Abstract
Global warming and eutrophication contribute to frequent occurrences of toxic algal blooms in freshwater systems globally, while there is a limited understanding of their combined impacts on toxin-producing algal species under interspecific competitions. This study investigated the influences of elevated temperatures, lights, nutrient enrichments and interspecific interactions on growth and microcystin (MC) productions of Microcystis aeruginosa in laboratory condition. Our results indicated that elevated temperatures and higher nutrient levels significantly boosted biomass and specific growth rates of Microcystis aeruginosa, which maintained a competitive edge over Chlorella sp. Specifically, with phosphorus levels between 0.10 and 0.70 mg P L-1, the growth rate of Microcystis aeruginosa in mixed cultures increased by 23 %-52 % compared to mono-cultures, while the growth rate of Chlorella sp. shifted from positive in mono-cultures to negative in mixed cultures. Redundancy and variance partition analyses suggested that Chlorella sp. stimulate MC production in Microcystis aeruginosa and nutrient levels outshine temperature for toxin productions during competition. Lotka‒Volterra model revealed a positive correlation between the intensities of competitions and MC concentration. Our findings indicate that future algal bloom mitigation strategies should consider combined influence of temperature, nutrients, and interspecific competition due to their synergistic effects on MC productions.
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Neethu B, Ihjas K, Chakraborty I, Ghangrekar MM. Nickel adsorbed algae biochar based oxygen reduction reaction catalyst. Bioelectrochemistry 2024; 159:108747. [PMID: 38820671 DOI: 10.1016/j.bioelechem.2024.108747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 05/18/2024] [Accepted: 05/24/2024] [Indexed: 06/02/2024]
Abstract
Lately, the bio electrochemical systems are emerging as an efficient wastewater treatment and energy conversion technology. However, their scaling-up is considerably restrained by slow-rate of cathodic oxygen reduction reaction (ORR) or otherwise by the high cost associated with the available efficient ORR catalysts. In this investigation, a cost-effective and eco-friendly approach for synthesizing Ni based ORR catalyst utilizing biosorption property of microalgae is accomplished. The synthesised Ni adsorbed algal biochar (NAB) served as an efficient cathode catalyst for enhancing ORR in a microbial carbon-capture cell (MCC). On increasing the initial concentration of Ni2+ in the aqueous medium from 100 mgL-1 to 500 mgL-1, the biosorption capacity was found to increase from 3 mgg-1 to 32 mgg-1 of algae cell. The MCC operated with NAB based cathode catalyst loading of 2 mgcm-2 exhibited 3.5 times higher power density (4.69 Wm-3) as compared to the one with commercial activated carbon. A significant organic matter removal (82 %) in the anodic chamber with simultaneous algal biomass productivity in the cathodic chamber was attained by MCC with cathode loaded with 2 mgcm-2 of NAB. Hence, this easily synthesised low-cost catalyst, out of waste stream, proved its ability to improve the performance of MCC.
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Yuan S, Du M, Li X, Xu K, Zhang K, Liu X, Wang J. Adaptability and nutritional analysis of a newly isolated Chlorella sp. NeZha in brackish and marine environments with potential bioeconomic impacts. Front Nutr 2024; 11:1460675. [PMID: 39206305 PMCID: PMC11349555 DOI: 10.3389/fnut.2024.1460675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2024] [Accepted: 08/01/2024] [Indexed: 09/04/2024] Open
Abstract
Introduction The microalga Chlorella sp. NeZha, recently isolated from a balcony environment, shows significant adaptability across various salinity conditions, including seawater (SeaW), freshwater (FreshW), and high salinity levels (45‰). This study investigates its potential for sustainable aquaculture and biotechnological applications. Methods Morphological and genetic identification were conducted using optical microscopy and DNA sequencing. The microalga was cultivated in a 400 L outdoor photobioreactor, and its biochemical composition, including chlorophyll a, carbohydrate, protein, and lipid content, was analyzed. Its compatibility with zooplankton and growth in aquaculture wastewater were also evaluated. Results Chlorella sp. NeZha produced chlorophyll a at concentrations exceeding seaweed and Spirulina by 10- and 5-fold, respectively, with a dry weight chlorophyll a content of 34.25 mg/g and 25 pg./cell. The microalga also contained carbohydrate (~33%), protein (~20%), and lipids (~14%). It was compatible with zooplankton species, such as rotifers and brine shrimp, and showed promising growth in aquaculture wastewater. Discussion The findings suggest that Chlorella sp. NeZha is a viable candidate for sustainable aquaculture and biotechnological applications, offering high nutritional value and environmental resilience. Its adaptability to diverse salinity conditions and ability to thrive in wastewater highlight its potential for bioremediation and use as feedstock for zooplankton. Further research is recommended to optimize its cultivation and explore broader applications.
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Kadam RV, Rani V, Padmavathy P, Shalini R, Selvi MJT, Narsale SA. Assessment of heavy metals and environmental stress conditions on the production potential of polyunsaturated fatty acids (PUFAs) in indigenous microalgae isolated from the Gulf of Mannar coastal waters. ENVIRONMENTAL MONITORING AND ASSESSMENT 2024; 196:301. [PMID: 38400851 DOI: 10.1007/s10661-024-12447-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 02/12/2024] [Indexed: 02/26/2024]
Abstract
The present study evaluated the effects of heavy metals, viz., lead, mercury, and cadmium, on growth, chlorophyll a, b, c, carotenoids, and PUFA content of marine microalgae Chlorella sp. and Cylindrotheca fusiformis. At 96-h exposure, the IC50 values for Hg2+, Pb2+, and Cd2+ were 0.85 mg/L, 2.4 mg/L, and 5.3 mg/L respectively, in Chlorella sp. In C. fusiformis, IC50 values for Hg2+, Pb2+, and Cd2+ were 0.5 mg/L, 1.2 mg/L, and 3 mg/L respectively. The pigment contents of both microalgae were significantly affected upon heavy metal exposure. In Chlorella sp. and C. fusiformis, the exposed concentrations of Hg2+ averagely decreased the PUFA content by 76.34% and 78.68%, respectively. Similarly, Pb2+-exposed concentrations resulted in 54.50% and 82.64% average reductions in PUFA content of Chlorella sp. and C. fusiformis, respectively. Cd2+-exposed concentrations showed 32.58% and 40.54% average reduction in PUFA content of Chlorella sp. and C. fusiformis, respectively. Among the environmental stress conditions, the dark treatment has increased total PUFA content by 6.63% in Chlorella sp. and 3.92% in C. fusiformis. It was observed that the 50% nitrogen starvation (two-stage) significantly improved the PUFA production from 26.47 ± 6.55% to 40.92 ± 10.74% in Chlorella sp. and from 11.23 ± 5.01 to 32.8 ± 14.17% in C. fusiformis. The toxicity for both microalgae was followed in the order Hg2+ > Pb2+ > Cd2+. Among the two species, Chlorella sp. has shown a high tolerance to heavy metals and can be effectively utilized in PUFA production.
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Das T, Nur S, Haque ME, Acharjee MR, Newase S, Afrin S, Khatoon H. Data on growth performance of marine Chlorella sp. cultured in different cost-effective media. Data Brief 2024; 52:109894. [PMID: 38161659 PMCID: PMC10754696 DOI: 10.1016/j.dib.2023.109894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 11/18/2023] [Accepted: 11/27/2023] [Indexed: 01/03/2024] Open
Abstract
This paper presents the data on growth performance of marine Chlorella sp. cultured in different cost-effective media including cow dung, cow urine, poultry litter, compost, NPK (nitrogen, phosphorus, and potassium), and UTR (Urea, TSP, and red potash). Growth curve of Chlorella sp. was determined at 5 mg of cow dung, poultry litter, compost, NPK, UTR and 5 µL of cow urine per 350 ml sea water (25 ppt) to identify the onset of stationary phase. Further four media among these were selected to continue the experiment at 8 mg and 11 mg of concentration. The higher cell densities were 4.21 × 106 and 4.18 × 106 cells/mL for NPK at 8 mg and 11 mg of concentration on 6th and 5th day, respectively. Cow dung with an 11 mg of concentration exhibited 2.67 × 106 cells/mL on the 3rd day, which is around 1.5 times greater than the highest growth in the same concentration of poultry litter. Chlorella sp. had a higher cell density in NPK media than in other media, however it was discarded since it is inorganic and costly. Due to the low cell density in cow urine media and the prolonged stationary phase in poultry litter media, the focus of the subsequent study was then placed on cow dung media. The data will contribute to the selection of locally available and cost-effective culture media by determining the stationary phases for specific microalgal species which will replace the costly and labor-intensive commercial media.
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Kumari S, Kumar V, Kothari R, Kumar P. Nutrient sequestration and lipid production potential of Chlorella vulgaris under pharmaceutical wastewater treatment: experimental, optimization, and prediction modeling studies. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:7179-7193. [PMID: 38158522 DOI: 10.1007/s11356-023-31719-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 12/21/2023] [Indexed: 01/03/2024]
Abstract
The efficient management and treatment of pharmaceutical industry wastewater (PIWW) have become a serious environmental issue due to its high toxicity. To overcome this problem, the present study deals with the phycoremediation of PIWW using Chlorella vulgaris microalga isolated from the Ganga River at Haridwar, India. For this, response surface methodology (RSM) and artificial neural network (ANN) tools were used to identify the best reduction of total phosphorus (TP) and total Kjeldahl's nitrogen (TKN) based pollutants along with the lipid production efficiency of C. vulgaris. Three different concentrations of pharmaceutical wastewater (0, 50, and 100%), operating temperatures (20, 25, and 30 °C), and light intensity (2000, 3000, and 4000 lx) were used to design the phycoremediation experiments having 6:18 h of dark/light period and reactor functional volume of 15L. Findings revealed that C. vulgaris was good enough to remove maximum TP (90.35%), TKN (83.55%) along 20.88% of lipid yield at 25.62 °C temperature, 60.73% PIWW concentration, and 4000 lx of light intensity, respectively. Based on the model performance and validation results, ANN showed more accuracy as compared to the RSM tool. Therefore, the findings of this study showed that C. vulgaris is capable of treating PIWW efficiently along with significant production of lipid content which can further be used in various applications including biofuel production.
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Akbarzadeh SS, Pourfakhraei E, Zargar M, Kashanchi M, Aghaei SS. Introducing of high rich lysine, arginine, and unsaturated fatty acids microalga as a food supplement. World J Microbiol Biotechnol 2023; 40:43. [PMID: 38105384 DOI: 10.1007/s11274-023-03839-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Accepted: 11/13/2023] [Indexed: 12/19/2023]
Abstract
Microalgae are powerful source for nutritionally valuable components as proteins, carbohydrates and especially unsaturated fatty acids. Microalgae may be employed in pharmaceutical, food, cosmetic, health industries, and biofuels. In this study for looking at high-level unsaturated fatty acids species, from 31 strains, by comparing growth curves, the best strain with a high growth rate and lipid content was selected by red Nile staining. It was determined by molecular identification that this strain belongs to the genus Chlorella sp. and is deposited into the Agricultural Biotechnology Research Institute of Iran Culture collection with culture collection number ABRIICC 30,041. Biomass analysis after growth optimization by response surface methodology showed that the selected strain had a specific growth rate of 0.216 ± 0.008 d-1, biomass productivity of 142.58 ± 4.41 mg/Ld, and lipid content of 13.9 ± 0.26% with a high level of unsaturated fatty acids of 53.15%. It also included 51.3 ± 0.53% protein with a very high quality essential amino acids of 40.36%, the most lysine (8.77%) and arginine (13.31%) has been reported until now, and 26.9 ± 0.23% carbohydrates in photoautotroph condition. By MTT assay, there is no effect of cytotoxicity. This research introduces a potent native strain comparable with commercial strains that can be a hopeful source for food supplements and valuable bioactive ingredients in functional foods.
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Plaza-Rojas CA, Amaya-Orozco NA, Rivera-Hoyos CM, Montaña-Lara JS, Páez-Morales A, Salcedo-Reyes JC, Castillo-Carvajal LC, Martínez-Urrútia W, Díaz-Ariza LA, Pedroza-Rodríguez AM. Use of biochar and a post-coagulation effluent as an adsorbent of malachite green, beneficial bacteria carrier, and seedling substrate for plants belonging to the poaceae family. 3 Biotech 2023; 13:386. [PMID: 37928437 PMCID: PMC10624780 DOI: 10.1007/s13205-023-03766-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 09/03/2023] [Indexed: 11/07/2023] Open
Abstract
Wastewater treatment plants produce solid and semi-solid sludge, which treatment minimises secondary environmental pollution because of wastewater treatment and obtaining new bioproducts. For this reason, in this paper, the co-pyrolysis of biogenic biomasses recovered from a biological reactor with immobilised fungal and bacterial biomass and a tertiary reactor with Chlorella sp. used for dye-contaminated wastewater treatment was carried out. Biogenic biomasses mixed with pine bark allowed the production and characterisation of two types of biochar. The raw material and biochar were on the "in vitro" germination of Lolium sp. seeds, followed by adsorption studies for malachite green (MG) dye using the raw material and the biochar. Results showed that using 60 mg L-1 of a cationic coagulant at pH 6.5 allowed for the recovery of more than 90% of the microalgae after 50 min of processing. Two biochar resulted: BC300, at pH 5.08 ± 0.08 and BC500, at pH 6.78 ± 0.01. The raw material and both biochars were co-inoculated with growth-promoting bacteria; their viabilities ranged from 1.7 × 106 ± 1.0 × 101 to 7.5 × 108 ± 6.0 × 102 CFU g-1 for total heterotrophic, nitrogen-fixing and phosphate-solubilising bacteria. Re-use tests on Lolium sp. seed germination showed that with the post-coagulation effluent, the germination was 100%, while with the biochar, with and without beneficial bacteria, the germination was 98 and 99%, respectively. Finally, BC500 adsorbed the highest percentage of malachite green at pH 4.0, obtaining qecal values of 0.5249 mg g-1 (R2: 0.9875) with the pseudo-second-order model. Supplementary Information The online version contains supplementary material available at 10.1007/s13205-023-03766-x.
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Mkpuma VO, Moheimani NR, Ennaceri H. Commercial paper as a promising carrier for biofilm cultivation of Chlorella sp. for the treatment of anaerobic digestate food effluent (ADFE): Effect on the photosynthetic efficiency. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 898:165439. [PMID: 37437632 DOI: 10.1016/j.scitotenv.2023.165439] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 07/04/2023] [Accepted: 07/08/2023] [Indexed: 07/14/2023]
Abstract
Microalgal technology is still economically unattractive due to the high cost associated with microalgal cultivation and biomass recovery from conventional suspension cultures. Biofilm-based cultivation is a promising alternative for higher biomass yield and cheap/easy biomass harvesting opportunities. Additionally, using anaerobic digestate food effluent (ADFE) as a nutrient source reduces the cultivation cost and achieves ADFE treatment as an added value. However, the search for locally available, inexpensive, and efficient support materials is still open to research. This study evaluates the potential of commercially available, low-cost papers as support material for biofilm cultivation of Chlorella sp. and treatment of ADFE. Among the four papers screened for microalgal attachment, quill board paper performed better in higher biomass yield and stability throughout the study period. The attached growth study was done in a modular food container vessel, using anaerobic digestate food effluent (ADFE) as a nutrient source and a basal medium as a control. The microalgae grew well on the support material with higher biomass yield and productivity of 108.64 g(DW) m-2 and 9.96 g (DW) m-2 d-1, respectively, in the ADFE medium compared with 85.87 g (DW) m-2 and 4.99 g (DW) m-2 d-1, respectively in the basal medium. Chlorophyll, a fluorescence (ChlF) probe, showed that cell density in the biofilm significantly changes the photosynthetic apparatus of the algae, with evidence of stress observed as the culture progressed. Also, efficient nutrient removal from the ADFE medium was achieved in the 100 %, 85 %, and 40.2 % ratios for ammoniacal nitrogen, phosphate, and chemical oxygen demand (COD). Therefore, using quill board paper as carrier material for microalgal cultivation offers promising advantages, including high biomass production, easy biomass harvesting (by scrapping or rolling the biomass with the paper), and efficient effluent treatment.
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Zhang H, Shangguan M, Zhou C, Peng Z, An Z. Construction of a mycelium sphere using a Fusarium strain isolate and Chlorella sp. for polyacrylamide biodegradation and inorganic carbon fixation. Front Microbiol 2023; 14:1270658. [PMID: 37869678 PMCID: PMC10585063 DOI: 10.3389/fmicb.2023.1270658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 09/12/2023] [Indexed: 10/24/2023] Open
Abstract
In the context of global demand for carbon reduction, the formation of inorganic carbon (IC) in the wastewater from oil flooding becomes a potential threat. In this study, Chlorella sp. and Fusarium sp. were used to assemble a fungal-algal pellet to degrade polyacrylamide (PAM) and fix IC in synthetic oil-flooding wastewater. The results showed that the combination of Chlorella sp. and Fusarium sp. was more effective at degrading PAM and removing carbon than a monoculture. With PAM as the sole nitrogen source, the degradation of PAM by the consortium was enhanced up to 35.17 ± 0.86% and 21.63 ± 2.23% compared with the monocultures of fungi or microalgae, respectively. The degradation of the consortium was significantly enhanced by the addition of an external nitrogen source by up to 27.17 ± 2.27% and 22.86 ± 2.4% compared with the monoculture of fungi or microalgae, respectively. This may depend on the effect of synergy between the two species. For the removal of IC from the water, the removal efficiency of the consortium was higher than that of the microalgae by 38.5 ± 0.08%, which may be attributed to the ability of the fungi to aid in the adsorption of nutrients and its assimilation by the microalgae. Therefore, the Fusarium-Chlorella consortium can effectively degrade PAM, while simultaneously fixing carbon, which provides a feasible scheme for the treatment and carbon neutralization of the wastewater that contains PAM.
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Hui GT, Meng TK, Kassim MA. Green ultrasonication-assisted extraction of microalgae Chlorella sp. for polysaturated fatty acid (PUFA) rich lipid extract using alternative solvent mixture. Bioprocess Biosyst Eng 2023; 46:1499-1512. [PMID: 37580470 DOI: 10.1007/s00449-023-02917-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 07/26/2023] [Indexed: 08/16/2023]
Abstract
Conventionally, microalgal lipid extraction uses volatile organic compounds as an extraction solvent. However, these solvents are harmful to human and environmental health. Therefore, this study evaluated the feasibility of alternative green solvents, namely, ethanol, dimethyl carbonate (DMC), cyclopentyl methyl ether (CPME), and 2-methyltetrahydrofuran (2-MeTHF) in lipid extraction from Chlorella sp. via ultrasound-assisted extraction (UAE). This study indicated that extraction parameters, such as ethanol-to-2-MeTHF ratio, solvent-to-biomass ratio, temperature, and time, significantly affected the crude lipid yield (P < 0.05). The highest crude lipid yield of 25.05 ± 0.924% was achieved using ethanol-2-MeTHF mixture (2:1, v/v) with a solvent-to-biomass ratio of 20:1 (v/w) at 60 °C for 25 min accompanying 100 W and 40 kHz. Ethanol-2-MeTHF-extracted lipids showed dominance in linoleic acid, α-linolenic acid, and palmitic acid. Overall this findings supported UAE using ethanol and 2-MeTHF as extraction solvents is a promising green alternative to conventional solvent extraction of lipids from microalgae.
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Fathy WA, Techen N, Elsayed KNM, Essawy EA, Tawfik E, Alwutayd KM, Abdelhameed MS, Hammouda O, Ross SA. Applying an internal transcribed spacer as a single molecular marker to differentiate between Tetraselmis and Chlorella species. Front Microbiol 2023; 14:1228869. [PMID: 37680531 PMCID: PMC10482269 DOI: 10.3389/fmicb.2023.1228869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 08/04/2023] [Indexed: 09/09/2023] Open
Abstract
In the realm of applied phycology, algal physiology, and biochemistry publications, the absence of proper identification and documentation of microalgae is a common concern. This poses a significant challenge for non-specialists who struggle to identify numerous eukaryotic microalgae. However, a promising solution lies in employing an appropriate DNA barcoding technique and establishing comprehensive databases of reference sequences. To address this issue, we conducted a study focusing on the molecular characterization and strain identification of Tetraselmis and Chlorella species, utilizing the internal transcribed spacer (ITS) barcode approach. By analyzing the full nuclear ITS region through the Sanger sequencing approach, we obtained ITS barcodes that were subsequently compared with other ITS sequences of various Tetraselmis and Chlorella species. To ensure the reliability of our identification procedure, we conducted a meticulous comparison of the DNA alignment, constructed a phylogenetic tree, and determined the percentage of identical nucleotides. The findings of our study reveal the significant value of the ITS genomic region as a tool for distinguishing and identifying morphologically similar chlorophyta. Moreover, our results demonstrate that both the ITS1 and ITS2 regions are capable of effectively discriminating isolates from one another; however, ITS2 is preferred due to its greater intraspecific variation. These results underscore the indispensability of employing ITS barcoding in microalgae identification, highlighting the limitations of relying solely on morphological characterization.
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Peng H, Xv X, Cui X, Fu Y, Zhang S, Wang G, Chen X, Song W. Physicochemical characterization and antioxidant activity of polysaccharides from Chlorella sp. by microwave-assisted enzymatic extraction. Front Bioeng Biotechnol 2023; 11:1264641. [PMID: 37635998 PMCID: PMC10448769 DOI: 10.3389/fbioe.2023.1264641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 08/02/2023] [Indexed: 08/29/2023] Open
Abstract
Microwave-assisted enzymatic extraction (MAEE) was used for the separation of polysaccharides from micro-Chlorella. The extraction condition of MAEE was optimized by Box-Behnken design and response surface methodology. Results showed that the optimal condition for the extraction of Chlorella sp. crude polysaccharides (CSCP) was at 50°C for 2.3 h with 380 W of microwave power and 0.31% of enzyme dosage. Under the optimal extraction condition, the extraction yield of CSCP reached 0.72%. Similarly, the α-amylase modification conditions of the CSCP were also optimized, in which the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging rate was used as the response value. The scavenging rate of DPPH free radicals was 17.58% when enzyme dosage was 271 U/g at 51°C for 14 min. Moreover, the enzyme-modified CSCP presented a typical heteropolysaccharide mainly including glucose (48.84%), ribose (13.57%) and mannose (11.30%). MAEE used in this work achieved a high extraction yield of CSCP, which provides an efficient method for the extraction of CSCP from Chlorella sp.
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Phan TM, Van Huynh B, Darsono SNAC, Pham TL, Bui HM. Ultrasound-Assisted Lipid Extraction from Chlorella sp.: Taguchi Design and Life Cycle Assessment. Mol Biotechnol 2023:10.1007/s12033-023-00836-6. [PMID: 37535160 DOI: 10.1007/s12033-023-00836-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 07/10/2023] [Indexed: 08/04/2023]
Abstract
The present study delved into the enhancement of essential oil (EO) extraction process from Chlorella sp. through the implementation of ultrasound-assisted extraction. The Taguchi method was instrumental in determining the ideal parameters for the extraction process, which encompassed ultrasonic amplitude, reaction duration, hexane/ethanol (HE/EtOH) ratio, and processing temperature. The empirical findings indicated that optimal EO yield was realized at an ultrasonic amplitude of 80%, a reaction timeframe of 15 min, a HE/EtOH proportion of 3:1, and a temperature setting of 40 °C. These optimal conditions were further substantiated through additional experimentation, resulting in an EO yield of 18.8 ± 0.2%. A fatty acid profile analysis disclosed that the extracted EO predominantly consisted of long-chain fatty acids (C14-C20), with Palmitic, Heptadecanoic, Oleic, and Linoleic acids featuring as the main components. Nevertheless, a high unsaturation rate of 37.9% in the EO could potentially render it vulnerable to oxidative deterioration during storage, consequently affecting the quality of the ensuing biodiesel. A life cycle assessment of the sonication technique utilized for biodiesel production from Chlorella sp. highlighted that lipid extraction was the principal contributor to global warming and ecotoxicity, as per the CML and TRACI methods. Hence, the ultrasound-assisted extraction of EO from Chlorella sp. appears to be a promising and ecologically viable substitute to conventional techniques employed for biodiesel production.
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Wang S, Zhao Q, Yu H, Du X, Zhang T, Sun T, Song W. Assessing the potential of Chlorella sp. phycoremediation liquid digestates from brewery wastes mixture integrated with bioproduct production. Front Bioeng Biotechnol 2023; 11:1199472. [PMID: 37388770 PMCID: PMC10303122 DOI: 10.3389/fbioe.2023.1199472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 06/05/2023] [Indexed: 07/01/2023] Open
Abstract
Digestates from different anaerobic digesters are promising substrates for microalgal culture, leading to effective wastewater treatment and the production of microalgal biomass. However, further detailed research is needed before they can be used on a large scale. The aims of this study were to investigate the culture of Chlorella sp. in DigestateM from anaerobic fermentation of brewer's grains and brewery wastewater (BWW) and to explore the potential use of the biomass produced under different experimental conditions, including diverse cultivation modes and dilution ratios. Cultivation in DigestateM initiated from 10% (v/v) loading, with 20% BWW, obtained maximum biomass production, reaching 1.36 g L-1 that was 0.27g L-1 higher than 1.09 g L-1 of BG11. In terms of DigestateM remediation, the maximum removal of ammonia nitrogen (NH4 +-N), chemical oxygen demand, total nitrogen, and total phosphorus reached 98.20%, 89.98%, 86.98%, and 71.86%, respectively. The maximum lipid, carbohydrate, and protein contents were 41.60%, 32.44%, and 27.72%, respectively. The growth of Chlorella sp. may be inhibited when the Y(II)-Fv/Fm ratio is less than 0.4.
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Shanmuganathan R, Le QH, Aloufi AS, Gavurová B, Deepak JR, Mosisa E, R PT. High efficiency lipid production, biochar yield and chlorophyll a content of chlorella sp. microalgae exposed on sea water and TiO 2 nanoparticles. ENVIRONMENTAL RESEARCH 2023:116263. [PMID: 37247655 DOI: 10.1016/j.envres.2023.116263] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 05/13/2023] [Accepted: 05/26/2023] [Indexed: 05/31/2023]
Abstract
This study explores the challenges facing microalgae biofuel production, specifically low lipid content and difficulties with algal cell harvesting. The purpose of the research is to investigate the effect of seawater content and nanoparticle concentration on freshwater microalgae growth and biofuel production. The principal results of the study show that increasing the proportion of seawater and nanoparticles enhances the lipid content and cell diameter of microalgae, while excessive concentrations of nanoparticles and low seawater content lead to reduced microalgae growth. Furthermore, an optimal cell diameter was identified at a nanoparticle concentration of 150 mg/L. The study also reveals that increasing seawater content can decrease zeta potential and increase chlorophyll a content due to the concentration of dissolved organic matter. Increasing the seawater content from 0% to 25% decreased zeta potential by 1% owing to the instability and aggregation of the cells. Chlorophyll a for the 0% seawater was 0.55 which is increased to 1.32 only due to the increase in the seawater content. This significant increase is due to the concentration of dissolved organic matter in seawater. Additionally, the presence of seawater positively affects microalgae metabolic activity and biochar yield. The findings of this study offer valuable insights into the potential for optimizing microalgae biofuel production. The use of seawater and nanoparticles has shown promise in enhancing microalgae growth and biofuel yield, and the results of this study underscore the scientific value of exploring the role of seawater and nanoparticles in microalgae biofuel production. Further research in this area has the potential to significantly contribute to the development of sustainable energy solutions.
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Oliveira APDS, Assemany P, Covell L, Calijuri ML. Copper multifaceted interferences during swine wastewater treatment in high-rate algal ponds: alterations on nutrient removal, biomass composition and resource recovery. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 324:121364. [PMID: 36849087 DOI: 10.1016/j.envpol.2023.121364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 12/15/2022] [Accepted: 02/24/2023] [Indexed: 06/18/2023]
Abstract
Microalgae cultivation in swine wastewater (SW) allows the removal of nutrients and biomass production. However, SW is known for its Cu contamination, and its effects on algae cultivation systems such as high-rate algal ponds (HRAPs) are poorly understood. This gap in the literature limits the proposition of adequate concentrations of Cu to optimise SW treatment and resource recovery in HRAPs. For this assessment, 12 HRAPs installed outdoors were operated with 800 L of SW with different Cu concentrations (0.1-4.0 mg/L). Cu's interferences on the growth and composition of biomass and nutrient removal from SW were investigated through mass balance and experimental modelling. The results showed that the concentration of 1.0 mg Cu/L stimulated microalgae growth, and above 3.0 mg Cu/L caused inhibition accompanied by an accumulation of H2O2. Furthermore, Cu affected the contents of lipids and carotenoids observed in the biomass; the highest concentration was observed in the control (16%) and 0.5 mg Cu/L (1.6 mg/g), respectively. An innovative result was verified for nutrient removal, in which increased Cu concentration reduced the N-NH4+ removal rate. In contrast, the soluble P removal rate was enhanced by 2.0 mg Cu/L. Removal of soluble Cu in treated SW reached 91%. However, the action of microalgae in this process was not associated with assimilation but with a pH increase resulting from photosynthesis. A preliminary evaluation of economic viability showed that the commercialisation of biomass considering the concentration of carotenoids obtained in HRAPs with 0.5 mg Cu/L could be economically attractive. In conclusion, Cu affected the different parameters evaluated in this study in a complex way. This can help managers consort nutrient removal, biomass production, and resource recovery, providing information for possible industrial exploitation of the generated bioproducts.
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Sawasdee N, Jantakee K, Wathikthinnakon M, Panwong S, Pekkoh J, Duangjan K, Yenchitsomanus PT, Panya A. Microalga Chlorella sp. extract induced apoptotic cell death of cholangiocarcinoma via AKT/mTOR signaling pathway. Biomed Pharmacother 2023; 160:114306. [PMID: 36738497 DOI: 10.1016/j.biopha.2023.114306] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 01/17/2023] [Accepted: 01/25/2023] [Indexed: 02/05/2023] Open
Abstract
Cancer is the leading cause of death worldwide. Drug resistance and relapse after current standard treatments frequently occur; thus, alternative and effective treatments are required. Algae and cyanobacteria are abundant organisms that serve as bioresources of nutrients/metabolites, which are attractive sources of numerous bioactive compounds for drug discovery. In the present study, we, therefore, investigated anti-cancer activities of crude polysaccharide and ethanolic extracts from Chlorella sp., Sargassum spp., and Spirulina sp. against cell lines of five top-leading cancers including lung cancer (A549), cervical cancer (Hela), breast cancer (MCF7), hepatocellular carcinoma (Huh7), and cholangiocarcinoma (CCA; KKU213A). Only ethanolic extracts of Chlorella sp. showed consistent inhibition of growth of all cancer cell types. CCA was the most sensitive to Chlorella sp. ethanolic extract with CC50 of 277.4, 400.5, and 313.4 µg/mL for KKU055, KKU100, and KKU213A cells, respectively. Flow cytometric analysis demonstrated that CCA cell death was triggered via apoptosis pathway in accompany with lowering procaspase-3, -8, and -9 and increasing caspase enzymatic activity in addition to reducing anti-apoptosis Bcl-2 protein. Interestingly, the treatment of the extract at 400 µg/mL greatly inhibited the AKT/mTOR survival signaling as evidenced by significant reduction of phosphorylated-AKT and phosphorylated-mTOR proteins. The presence of reported bioactive compounds, gallic acid, and lutein, were confirmed in Chlorella sp. extract by high-performance liquid chromatography. Gallic acid and lutein treatment caused a significant reduction of KKU055, KKU100, and KKU213A cell viability. This study demonstrated the anti-cancer effect of Chlorella sp. ethanolic extract to promote cancer cell death via inhibition of AKT/mTOR pathway.
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Zheng S, Wu A, Wang H, Chen L, Song J, Zhang H, He M, Wang C, Chen H, Wang Q. Purification efficiency of Pyropia-processing wastewater and microalgal biomass production by the combination of Chlorella sp. C2 cultivated at different culture temperatures and chitosan. BIORESOURCE TECHNOLOGY 2023; 373:128730. [PMID: 36791980 DOI: 10.1016/j.biortech.2023.128730] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 02/06/2023] [Accepted: 02/08/2023] [Indexed: 06/18/2023]
Abstract
To elucidate the impacts of culture temperature on nutrient removal efficiency of Pyropia-processing wastewater (PPW) and microalgal biomass production, Chlorella sp. C2 was employed and cultivated in raw PPW under different temperatures. Results showed that, after incubating for 7 days, higher biomass (0.50 g/L) and total lipids (21.84 %) were attained at 35 °C. The maximal chemical oxygen demand (COD), phycobiliprotein, total nitrogen and total phosphorus removal rates were observed at 30-35 °C and separately reached 62.41 %, 92.61 %, 92.19 % and 98.33 %. Interestingly, COD removal efficiencies of Chlorella cells, cultivated for 3, 5 and 7 days at 30-35 °C, 15-25 °C and 10 °C respectively, could reach >75 % with assistance from 60-80 mg/L chitosan. Meanwhile, the clarification efficiency of chitosan on algal cells reached >95 %. It suggests that Chlorella strain cultured at altered temperatures could efficiently remove PPW nutrients assisted by moderate chitosan, simultaneously achieving the rapid harvest of microalgae.
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Wu H, Yang P, Li A, Jin X, Zhang Z, Lv H. Chlorella sp.-ameliorated undesirable microenvironment promotes diabetic wound healing. Acta Pharm Sin B 2023; 13:410-424. [PMID: 36815029 PMCID: PMC9939294 DOI: 10.1016/j.apsb.2022.06.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 04/29/2022] [Accepted: 05/12/2022] [Indexed: 11/01/2022] Open
Abstract
Chronic diabetic wound remains a critical challenge suffering from the complicated negative microenvironments, such as high-glucose, excessive reactive oxygen species (ROS), hypoxia and malnutrition. Unfortunately, few strategies have been developed to ameliorate the multiple microenvironments simultaneously. In this study, Chlorella sp. (Chlorella) hydrogels were prepared against diabetic wounds. In vitro experiments demonstrated that living Chlorella could produce dissolved oxygen by photosynthesis, actively consume glucose and deplete ROS with the inherent antioxidants, during the daytime. At night, Chlorella was inactivated in situ by chlorine dioxide with human-body harmless concentration to utilize its abundant contents. It was verified in vitro that the inactivated-Chlorella could supply nutrition, relieve inflammation and terminate the oxygen-consumption of Chlorella-respiration. The advantages of living Chlorella and its contents were integrated ingeniously. The abovementioned functions were proven to accelerate cell proliferation, migration and angiogenesis in vitro. Then, streptozotocin-induced diabetic mice were employed for further validation. The in vivo outcomes confirmed that Chlorella could ameliorate the undesirable microenvironments, including hypoxia, high-glucose, excessive-ROS and chronic inflammation, thereby synergistically promoting tissue regeneration. Given the results above, Chlorella is considered as a tailor-made therapeutic strategy for diabetic wound healing.
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Lv M, Zhao Y, Li D, Zhang B, Li L, Liu Z, Tang X, Zhao Y. The adsorption and absorption kinetics of BDE-47 by Chlorella sp. and the role of extracellular polymer substances influenced by environmental factors. ENVIRONMENTAL RESEARCH 2023; 216:114698. [PMID: 36328222 DOI: 10.1016/j.envres.2022.114698] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 10/08/2022] [Accepted: 10/27/2022] [Indexed: 06/16/2023]
Abstract
Microalgae act as the entrance of polybrominated diphenyl ethers (PBDEs) from abiotic to biotic environments, which controlled the environmental fate of PBDEs in aquatic environments. Combing with typical coastal environmental characteristics including extracellular polymer substances (EPS) enrichment, light limitation and nitrogen starvation, the changes of adsorption and absorption kinetics of BDE-47 by Chlorella sp. and the role of EPS therein were investigated. The results quantified the adsorption and absorption kinetics of BDE-47 by Chlorella sp. cells and fitted it by the Lagergren pseudo first order model. Furthermore, we found the adsorption and absorption kinetics could be changed by the above mentioned environmental factors. To be specific, the total BDE-47 adsorption amounts per microalgal cell were increased as the increase of ambient EPS (proteins or carbohydrates), attributing to the increase of soluble (SL)-EPS contents; increased total BDE-47 adsorption amounts but decreased absorption rates were found under light limitation and nitrogen starvation, which were attributed to increased bound (B)-EPS contents and protein/carbohydrates (P/C) ratios therein, respectively. Therefore, our study elucidated the adsorption and absorption kinetics of PBDEs by microalgae could be influenced by ambient environmental changes, clarified the roles of SL-EPS, B-EPS contents and P/C ratios, providing a solid basis for evaluating the environmental fate of PBDEs in the marine environments.
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Li J, Tang X, Pan K, Zhu B, Li Y, Wang Z, Zhao Y. Energy metabolism and intracellular pH regulation reveal different physiological acclimation mechanisms of Chlorella strains to high concentrations of CO 2. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 853:158627. [PMID: 36087671 DOI: 10.1016/j.scitotenv.2022.158627] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 09/05/2022] [Accepted: 09/05/2022] [Indexed: 06/15/2023]
Abstract
The intolerance of high CO2 in the exhaust gas is the "bottleneck" limiting the wide application of microalgae for CO2 biosequestration. Around this topic, we selected high-CO2-tolerant (LAMB 33 and 31) and nontolerant (LAMB 122) Chlorella strains to study their different energy metabolisms and cytoplasmic pH regulations in response to high CO2. Under 40 % CO2, LAMB 33 and 31 both showed elevated ATP synthesis, accelerated ATP consumption and fast cytoplasmic pH regulation while exhibiting different acclimating strategies therein: chloroplast acclimations were reflected by high chlorophyll contents in 33 but photosystem transitions in 31; faster mitochondrial acclimations occurred in 33 than in 31; cellular organic carbon mainly flowed to monosaccharide synthesis for 33 but to monosaccharide and protein synthesis for 31; and cytoplasmic pH regulation was attributed to V-ATPase in 31 but not in 33. All the above metabolic processes gradually collapsed in 122, leading to growth inhibition. Our study identified different metabolic acclimation strategies among Chlorella strains to high CO2 and provided new traits for breeding microalgae for CO2 biosequestration.
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