Genomic adaptation and metabolic hierarchy: Microbial community response to oxygen stress in community derived from sludge treating refinery wastewater

Abstract

The complexity of the metabolic networks in a microbial community is decided by the heterogeneity of available carbon sources such as in refinery wastewater treatment plants. The organic loading due to diverse hydrocarbons could be shunted in the metabolic network through different oxygenase's which work on different redox levels. In this study, the three different bioreactors in the continuous mode were set up with different dissolved oxygen (DO) levels with phenol as a representative carbon source. To understand the metabolic diversity, co-assembly from metagenome data was done leading to generation of 27 high-quality genomes which together represent 70% of the community. Clustering at various functional levels along with genomic abundance shows the existence of functional hierarchy in the community. Genomic comparison revealed the various scenarios of genomic adaptation and existence of metabolic plasticity which all together increases the community metabolic capacity. The whole experimental design combined with genome level functional entanglement between community member serve as a method for improvement of wastewater treatment processes under perturbing conditions.