Synthetic bacterial community based on microbial interactions for bioremediation of petroleum contaminated sites.

Constructing synthetic bacterial communities (SynComs) is beneficial for bioremediation of petroleum-contaminated sites. In this study, the distribution and response mechanisms of microbial communities to environmental factors were analyzed in refinery soil and groundwater in order to construct SynComs. Seven keystone petroleum-degrading strains were identified by bacterial co-occurrence networks. These seven strains were constructed into SynComs of three different ratios according to abundance of co-occurrence network (FB), abundance of operational taxonomic units (OTU) and equal proportion (EQ). C10-C40 hydrocarbons were the predominant pollutants in soil, and the pollution of groundwater was dominated by benzene, toluene and xylenes (BTEX). Aromatic degrading bacteria with iron and manganese-reducing and denitrifying bacteria were the keystone in Modules 0 and 1 of the co-occurrence network. The proportion of stochastic processes on bacterial community decreased from 75.44 % to 52.38 % in petroleum-contaminated soil. From degradation experiment, the FB showed the highest degradation efficiency, particularly for benzene (FB: 88.77 %; OTU: 79.75 %; EQ: 79.61 %). The bacterial species within SynComs enhanced the degradation of pollutants by strengthening synergistic degradation, improving microbial community stability and reducing the accumulation of intermediate products. Based on the interaction between bacteria and their correlation with pollutants, SynComs were likely to have more degradation potential. This study provides a new perspective on achieving efficient petroleum hydrocarbon-degrading communities in the remediation of contaminated sites.