Interaction Of Culturable Microorganisms In Activated Sludge And Taxonomic Analysis Of New Bacteria

Antibiotic wastewater has complex composition and strong biological toxicity,and direct discharge of antibiotics has great safety risks.Activated sludge process is the most widely used wastewater treatment technology,in which microorganisms play a vital role in the degradation and transformation of pollutants.Therefore,it is of great significance to study the microbial resources and ecology in activated sludge for the effective treatment of antibiotic wastewater.This topic took the activated sludge in antibiotic wastewater treatment plant as the research object,analyzed the changes of bacterial community structure in the process of antibiotic wastewater treatment,at the same time used a variety of isolation methods to obtain the bacterial resources in it,and carried on a preliminary exploration on the survival and interaction of strains in antibiotic wastewater.The results will provide theoretical reference and strain resources for the biological treatment of antibiotic wastewater.Activated sludge samples were collected from the sewage treatment plant of Shandong Lukang Biological Company at different time points(January 2021-August 2021).Firstly.16S rRNA gene amplicon sequencing showed that the community richness and diversity were the highest when the activated sludge was newly added,and then decreased gradually.The dominant groups in activated sludge are Proteobacteria,Actinobacteriota,Firmicutes and Bacteroidota,and they always maintain the dominant position.The proportion of Proteobacteria increased continuously,eventually increasing to 71%,in which Acidovorax accounted for 18.2%of all sequences.The number of Myxococcota decreased continuously,and the relative abundance of Haliangium in Myxococcota increased gradually.Community composition,community richness and community diversity can be restored by replacing the new activated sludge.In addition to diversity sequencing,dilution coating,prey induction,environmental pressure and other strategies were used to isolate and culture bacteria in activated sludge,especially mucobacteria.A total of 411 strains of bacteria were obtained,which were distributed in Actinobacteriota(21 strains),Bacteroidota(26 strains),Firmicutes(31 strains),Myxococcota(99 strains)and Proteobacteria(234 strains),among which 64 strains were potential new bacteria.There is a lack of knowledge about the survival of acquired bacteria in antibiotic wastewater and the interactions between strains.By detecting the sequence number of a single strain cultured in antibiotic waste water for one week,85 strains were found.Data analysis showed that 42 strains were found to be non-viable,and some of them were shown to be dominant in the analysis of activated sludge flora.In order to detect the interaction between strains in the original wastewater environment,the strains were combined in pairs and cultured in antibiotic wastewater.Results 68 strains were detected,among which 13 strains could survive alone,12 strains could coexist in pairs,and 43 strains could either survive alone or coexist.There were 27 strains that could not survive when cultured alone,but survived in combination culture,among which 9 strains were dominant in activated sludge in sewage treatment plants.Three potential new strains of Flavobacterium were obtained in the pure culture process.We studied the phylogeny,morphological characteristics,physiological and biochemical classification characteristics and chemical composition characteristics of potential new strains and their reference bacteria.a new species of Flavobacterium odorum was established,the representative strain is HXWNR29T;Flavobacterium fragilis was established,the representative strain is HXWNR69T;Flavobacterium odorum was established,the representative strain is HXWNR70T.