Network And Meta-Omics Reveal The Key Degrader And Cooperation Patterns In An Efficient 1,4-Dioxane-Degrading Microbial Community

Abstract

Background: 1,4-dioxane is an emerging wastewater contaminant with probable human carcinogenicity. Our current understanding of microbial interactions during 1,4-dioxane biodegradation process in mix cultures is limited. Here, we applied metagenomic, metatranscriptomic and co-occurrence network analyses to unraveling the microbial cooperation between degrader and non-degraders in an efficient 1,4-dioxane-degrading microbial community CH1.Results: The 1,4-dioxane degrading bacterium, Ancylobacter polymorphus ZM13, was isolated from CH1 and proved to be the key degrader because of the high relative abundance, highly expressed toluene monooxygenase genes tmoABCDEF and high betweenness centrality of networks. The strain ZM13 cooperated obviously with 6 bacterial genera in the network, among which Xanthobacter and Mesorhizobium were proved to be involved in the intermediate metabolism with responsible genes encoding alcohol dehydrogenase (adh), aldehyde dehydrogenase (aldh), glycolate oxidase (glcDEF), glyoxylate carboligase (gcl), malate synthase (glcB) and 2-isopropylmalate synthase (leuA) upregulated. Also, 1,4-dioxane facilitated the shift of biodiversity and function of CH1, and those cooperators of CH1 cooperated with ZM13 in the way of providing amino acids or fatty acids and relieving environmental stresses to promote biodegradation.Conclusions: This study revealed the biodiversity, community structure, microbial functions and interactions in a microbial community CH1 during the efficient 1,4-dioxane degradation and proved the degrader Ancylobacter polymorphus ZM13 that isolated from CH1 was the key degrading bacterium. These results provide new insights into our understanding of how the key degrading bacterium interacted with cooperators in a 1,4-dioxane-degrading community, and has important implications for predicting microbial cooperation and constructing highly efficient synthetic 1,4-dioxane-degrading communities.