Study On Terramycin Mycelial Dreg Aerobic Composting Enhanced With High-Efficiency Microbial Agent And Its Effect On Removal Of Antibiotic Resistance Genes

Antibiotic residue and its antibiotic residues are a kind of new pollutants,and will produce Antibiotic Resistance Genes（ARGs）,its persistent residue and transmission in the environment is more harmful than antibiotics.Therefore,it is worth paying attention to find a new way to remove residual antibiotics and ARGs in antibiotic mycelial dreg,and further explore the dynamic change and transfer mechanism of ARGs in the aerobic composting process of terramycin mycelial dreg.Therefore,the effects of high-efficiency complex bacterial agent on basic physical and chemical parameters,microbial community,residual terramycin and ARGs in aerobic composting process of terramycin residue were investigated.The main conclusions are as follows:1)A Thermoactinomyces vulgaris strain GS2 was selected to improve the effect of aerobic composting,and its protease activity was up to 25.42 U·m L^-1.Protease live to rise further,with the preliminary screening of Geobacillusthermodenitrificans LB6 and Bacillus subtilis LB7 for compatibility,through orthogonal experiment,determine the GS2:LB6:LB7 was 5:3:12,and the efficient composite microbial agent was prepared.Its enzyme activity reached 42.73 U·m L^-1.2)The control group was compost without adding high efficiency compound microbial agent.The effects of high efficiency compound bacterials and commercial biological bacterials on physicochemical properties,toxicity and fertilizer efficiency of terramycin mycelial dreg aerobic compost were studied.The maximum temperature of the compost was 70.55℃,which was beneficial to the retention of nitrogen source,and the seed germination index（GI）of the compost product was increased to 107.31%.The degradation rate of organic matter increased by 5.52%.The finished compost products can basically meet the Organic Fertilizer Standard（NY/T525-2021）.3)To explore the effects of high efficiency compound microbial microbial agent on terramycin residue,microbial community and ARGs in terramycin.The results showed that the degradation rate of residual terramycin was increased significantly after the addition of high efficiency microbial compound bacteria,reaching 99.17%.The degradation rates of Van RA,Van T and dfr A24 increased by 40.81%,5.65%and 54.18%,respectively.The abundance of Thermophilic bacteria genera,and the relative abundance of pathogenic bacteria decreased.It is concluded that the difference of bacterial abundance caused by temperature changes in different composting stages may be the internal mechanism of ARG changes in composting process.This study illustrates that there are a variety of ARGs in terramycin mycelial dreg aerobic compost,which changes the interaction mode of the protobacterial community in compost,reduces the complexity of the bacterial community,reduces the number of ARGs-carrying microorganisms,and leads to the decline of some ARGs abundance,thus affecting the internal mechanism of ARG changes in the compost process.It provides theoretical reference and technical support for the harmless treatment and resource utilization of antibiotic mycelial dreg.