Mechanisms Of Nitrogen And Phosphorus And Antibiotic Resistance Genes Removal By Algal-Bacterial Consortia

Water pollution is one of the most serious environmental problems at present.The traditional sewage treatment technology has been continuously optimized and improved.At the same time,more and more researchers have also turned their attention to new technologies.Algae can effectively remove water pollutants and transform them into high value-added by-products,so it has attracted widespread attention.In this study,we investigated the removal mechanism of conventional pollutants from artificial wastewater by using Chlorella vulgaris and Bacillus licheniformis to form an algae-bacterial consortium system.The results showed that the appearance of Bacillus licheniformis could promote the growth of Chlorella vulgaris,and Bacillus licheniformis formed an algal consortium with Chlorella vulgaris in the form of adhesion or individual aggregation.The removal rates of TN,TP and COD by the algal-bacterial consortium were64.1%,46.3% and 69.8%,respectively.The consortium system was more effective than the single algae or single bacteria system in removing conventional pollutants from water bodies.In addition,Bacillus licheniformis in the algal symbiosis promoted the enhancement of amino acid,carbohydrate and organic acid metabolic processes in the algal cells,and also enhanced the carbon fixation process,TCA cycle in the cells of common Chlorella vulgaris.Bacillus licheniformis in the algal consortium enhanced the utilization of N and P pollutants in the water column by enhancing the above metabolic processes in the algal cells.This study also took antibiotic resistance genes(ARGs)as the research object to explore the changes of ARGs content in aqueous solution,the material changes of ARGs into the algal system,and the movement trajectory of exogenous ARGs into the cell interior.The results showed that the algae-bacterial consortium system had excellent ARGs removal ability,and the removal rate of ARGs was(98.5 ± 1.2)%;Glycoprotein has an effect on the removal of ARGs;The gene replication of ARGs is in Chlorella vulgaris and Bacillus licheniformis consortium is inhibited.As a new type of wastewater treatment technology,this study provides some reference for the removal of nitrogen and phosphorus nutrients in water and the horizontal transfer of ARGs by algae and bacteria symbionts.