Gene expression profiling of sulfate reducing bacteria under varying copper concentrations

Author: Priya Saxena, Department of Chemical and Biological Engineering (Equal contribution)

Co-Author: Abhilash Kumar Tripathi, Department of Chemical and Biological Engineering (Equal contribution)

Contributor: Payal Thakur, Department of Chemical and Biological Engineering

Contributor: Shailabh Rauniyar, Department of Chemical and Biological Engineering

Mentor: Dr. Rajesh Sani, Department of Chemical and Biological Engineering

Sulfate reducing bacteria (SRB) are capable of forming biofilms that results in microbial induced corrosion (MIC) of metals and threatens a range of multi-billion-dollar industries. MIC accounts for 20–40% of the annual corrosion costs, which have been estimated to up to $276 billion. Copper (Cu) has been the material of choice for piping in these industries because of its toxicity to microbes. However, certain SRBs can induce copper corrosion which presents two fundamental problems: structural damage and human health risk from the release of Cu ions into the drinking water. Our research majorly focuses on a model SRB (i.e., Desulfovibrio alaskensis G20, DA G20) whose biofilm induces MIC in Cu. to the present study evaluated the gene expression profiles of DA G20 (transcriptomics) when grow with different concentrations of Cu. Our results show that in 5µM Cu, 47.4% genes were downregulated and 52.6% were upregulated while in 15µM Cu 49.7% genes were upregulated and 50.3% are downregulated. The gene Dde_1676 (Radical SAM domain – containing protein) responsible for metal ion binding was upregulated by 7 and 8-fold in 5µM and 15µM Cu, respectively. The gene Dde_0356, (Flagellar basal body rod protein) which helps in motility, was downregulated 12 and 7-fold in 5µM and 15µM Cu, respectively. The downregulation of Dde_0356 indicates the propensity of DA G20 towards biofilm formation in the presence of Cu ions. The gene level data obtained in this study will be used to identify key metabolic functions involved in Cu resistance. This information could be used to design strategies to inhibit biofilm formation by SRB.