The metabolic landscape of the bacteria Rhodococcus erythropolis used in the biodesulfurization of petroleum products: an emphasis on 2-hydroxybiphenyl.

Microorganisms produce diverse classes of metabolites under various physiological conditions. Many bacterial strains have been reported to carry out the process of desulfurization in a cost-effective manner by converting dibenzothiophene (DBT) into 2-hydroxybiphenyl (2-HBP) and then using the 2-HBP as a carbon source for growth and development. Key rate-limiting factors and an increased concentration of 2HBP (400 µM) affect the biodesulfurization activity of bacteria through the produced metabolites. Thus, this study was designed to explore the nature of the metabolites produced by Rhodococcus erythropolis in the presence of DBT and 2HBP supplemented with a culture medium. A total of 330 metabolites were detected, and the key metabolites identified were 11Z-eicosaenoyl-EA, 1-carboxyethylisoleucine, 1(3)-glyceryl-PGF2alpha, taurine, 2-hydroxynicotinic acid, 4,4-dimethyl-14alpha-hydroxymethyl-5alpha-cholest-8-en-3beta-ol, and 10-nitrooleic acid. The supplementation of DBT and DBT-2HBP resulted in the differential regulation of these metabolites, either through downregulation or overexpression. Furthermore, at high concentrations of 2-HBP, 1-carboxyethylisoleucine, taurine, 2-hydroxynicotinic acid, and nicotinic acid were upregulated. This work proposes that the identified metabolites may play a role in bacteria-mediated desulphurization and could be beneficial in developing a cost-effective method of desulphurization for refining petroleum.