Effect Of GR24 On Biogas Upgrade And Nutrient Removal By Microalgae-based Technology

A large amount of N,P nutrients and pollutants were discharged into rivers,lakes and other water bodies,causing water ecosystems to face severe eutrophication and the threat of chemical and serious pollution nowadays.This article aimed to purify the biogas slurry and upgrade the biogas,and uses the freshwater microalga Chlorella vulgaris as the biological material to explore the effect of the new plant hormone Strigolactones（SLs）analogue GR24 concentration on microalgae organisms,including removing the conventional and special pollutants in simulated biogas slurry and the concentration of CO₂ in simulated biogas,and constructing the algae-bacterial symbiont to study the impacts of biological purification effect of GR24 concentration under red-blue composite light.Hope to help establish an effective energy management system,and provide new ideas for the treatment of polluted water bodies.The study indicated that:（1）Chlorella vulgaris was cultivated to remove the conventional pollutants in the biogas slurry and purify the biogas of pig farm and upgrade the biogas,and the effect of GR24 concentration on it was studied.The best growth rate and photosynthetic performance were obtained by the microalgae cultured with 10^-7 M GR24.Under the induction of 10^-7 M GR24,the removal efficiency of COD,TN and CO₂ were78.62±2.36%,76.47±1.53%and 64.05±1.15%,respectively.In addition,the highest TP removal efficiency of 80.27±1.93%was obtained at 10^-9 M.Taking the removal efficiencies of pollutants and CO₂ into account,the optimal GR24 concentration range of biological purification of simulated biogas slurry was determined to be 10^-9-10^-7 M.（2）Chlorella vulgaris was cultivated in BG11 medium supplemented with three50 mg·L^-1 tetracycline antibiotics（Oxytetracycline Hydrochloride,Tetracycline Hydrochloride,Chlortetracycline Hydrochloride）,and the effect of GR24concentration on it was studied.The microalgae with the same initial concentration had the highest removal efficiency of high concentration of Tetracycline Hydrochloride,reaching 88%.GR24 had no effect on the efficiency of microalgae to remove 50mg·L^-1 tetracycline antibiotics,but it had a positive effect on the growth of microalgae in a high-concentration antibiotic environment.The optimal concentration GR24 range was 10^-7-10^-6 M.High-concentration antibiotics inhibited the photosynthetic performance of microalgae,and increased the degree of intracellular oxidative damage,but GR24 helped alleviate it to a certain extent.（3）Chlorella vulgaris and Ganoderma lucidum were used to construct an algae-bacterial symbiosis,and the effect of light strategy on the purification of biogas from the GR24 algal-bacterial symbiote was studied.The optimal mixed intensity ratio（red-blue）was 5:5 under the induction of GR24.The nutrient removal efficiencies were about 80%,and the highest CO₂ removal efficiency was close to 60%.The optimal concentration range for purification of biogas slurry and biogas was 10^-9 M and 10^-7 M,respectively.In conclusion,the study focused on the influences that GR24 on the removal of conventional and special pollutants from Chlorella vulgaris and symbiosis.It was hoped to provide a theoretical basis for the practical application of biological purification technology,and had guiding significance for the treatment of water pollution and the realization of water ecological restoration.