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Effects of a phosphorus-solubilizing bacteria (PSB) Bacillus megatherium on growth and lipid production of Chlorella sorokiniana were investigated in synthesized swine wastewater with dissolved inorganic phosphorus (DIP), insoluble inorganic phosphorus (IIP), and organic phosphorus (OP). The results showed that the PSB significantly promoted the algal growth in OP and IIP, by 1.10 and 1.78-fold, respectively. The algal lipid accumulation was also greatly triggered, respectively by 4.39, 1.68, and 1.38-fold in DIP, IIP, and OP. Moreover, compared with DIP, OP improved the oxidation stability of algal lipid by increasing the proportion of saturated fatty acids (43.8 % vs 27.9 %), while the PSB tended to adjust it to moderate ranges (30.2-41.6 %). Further, the transcriptome analysis verified the OP and/or PSB-induced up-regulated genes involving photosynthesis, lipid metabolism, signal transduction, etc. This study provided novel insights to enhance microalgae-based nutrient removal combined with biofuel production in practical wastewater, especially with complex forms of phosphorus., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

This study explored the feasibility of a coupled system for antibiotic removal and biofuel production through microalgae cultivation. Initial, batch culture experiments demonstrated that sulfadiazine (SDZ) had an inhibitory effect on Chlorella sp. G-9, and 100.0 mg L-1 SDZ completely inhibited its growth. In order to improve SDZ removal efficiency by microalgae, three membrane photobioreactors (MPBRs) with different hydraulic retention times (HRTs) were established for continuous microalgae cultivation. The efficient coupling of SDZ removal and microalgal lipid production was achieved through the gradual increment of influent SDZ concentration from 0 to 100.0 mg L-1. The reduction in SDZ ranged between 57.8 and 89.7%, 54.7-91.7%, and 54.6-93.5% for the MPBRs with HRT of 4 d, 2 d, and 1 d, respectively. Chlorella sp. Was found to tolerate higher concentrations of SDZ in the MPBR system, and the resulting stress from high concentrations of SDZ effectively increased the lipid content of microalgae for potential biodiesel production. With the increase of influent SDZ concentration from 0 to 100.0 mg L-1, the lipid content of microalgae increased by 43.5%. Chlorophyll content, superoxide dismutase activity, and malondialdehyde content of microalgae were also evaluated to explore the mechanism of microalgae tolerance to SDZ stress in MPBR., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Saline wastewater was used in this study to culture freshwater microalgae Chlorella pyrenoidosa in sequencing batch photobioreactor to improve the sedimentation and lipid production of algal cells. Influent salinity of 0.5% or above effectively promoted the sedimentation of microalgae in the settling stage of photobioreactor, and greatly reduced the algal biomass in effluent. The mechanism of the saline wastewater in improving the sedimentation of microalgae included decreasing zeta potential, increasing cell particle size and promoting extracellular polymeric substances synthesis, which varied with influent salinity. Saline wastewater also promoted the lipid accumulation in microalgae. Lipid content of microalgae increased with increasing influent salinity. However, the growth of microalgae was greatly inhibited at the influent salinity of 2.0% and 3.0%. Therefore, the PBR with influent salinity of 1.0% achieved the highest productivity of microalgae lipid. The saturation of fatty acids of microalgae gradually increased with increasing influent salinity., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

This study investigated the possibility of coupling anaerobic hydrolysis in an anaerobic membrane bioreactor (AnMBR) with mixotrophic microalgae cultivation in a membrane photobioreactor (MPBR) for the sustainable treatment of municipal wastewater. Using the hydrolyzed wastewater discharged from AnMBR, Chlorella pyrenoidosa in MPBR grew in a mixotrophic mode and realized rapid growth. During the stable operation, MPBR achieved average carbon capture rate of 42.82 mg L -1 d -1 and algal lipid production rate of 19.66 mg L -1 d -1 . The average reduction in TN, TP, and TOC during stable operation was 96.7%, 98.0%, and 95.9%, respectively. Mass balance analysis showed that the overall system captured 14.76 mg of carbon from the atmosphere per liter of wastewater treated. Therefore, this AnMBR-MPBR hybrid system simultaneously realized advanced treatment of municipal wastewater, efficient production of algal lipid, and carbon capture from atmosphere, and thus has a good potential in the sustainable treatment of municipal wastewater., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

In this work, glucose addition (0.7 g l -1 ) almost doubled hydrogen yield of Chlorella pyrenoidosa (121.1 ml l -1 vs 65.5 ml l -1 ), with a positive correlation between hydrogen production and glucose consumption (-0.977, P < 0.01). When the electrons transport from water photolysis to algal hydrogenase was inhibited, the hydrogen productivity declined by 21.1%; whereas it dramatically decreased by 70.9% when the algal nicotinamide adeninedinucleotide dehydrogenase (NADH) was inhibited. Therefore, in the presence of glucose, the electrons for algae based hydrogen production would be mainly from glucose glycolysis rather than water photolysis. Further deuterated-glucose trial indicated that the glucose might serve as an electron donor for algal hydrogenases. Finally, a tentative electron transport route from glucose to algal hydrogenase was proposed, hoping to provide more scientific direction for further algae-based hydrogen production improvement., (Copyright © 2019 Elsevier Ltd. All rights reserved.)