Effect of nutrient and physical parameters on dibenzothiophene desulfurization activity of Streptomyces sp. VUR PPR 101 isolated from oil contaminated soils of mechanical workshops

Abstract

Motor vehicles use petroleum products and release sulfur dioxide gas which causes deleterious effects to environment and humans. The sulfur containing compounds present in petroleum products especially organosulfur compounds serve as major source of sulfur dioxide emission. During refining process, petroleum products are subjected to hydrodesulfurization for the removal of sulfur, which is not an efficient method and most of the organosulfur compounds are not eliminated particularly dibenzothiophene and its derivatives. A process known as biodesulfurization which employs microorganisms was suggested to be an alternative to hydrodesulfurization. The dibenzothiophene was selected as model organosulfur compound to perform biodesulfurization studies due its high recalcitrant nature. The microbes which remove sulfur via 4S pathway from organosulfur compounds (dibenzothiophene) are commercially important. In the present study, the effect of different nutrient sources (carbon, nitrogen and amino acid sources at different concentrations) and physical parameters like temperature and pH on dibenzothiophene desulfurization activity (via 4S pathway) of Streptomyces sp. VUR PPR 101 was studied and optimized. The optimum carbon and nitrogen sources for DBT biodesulfurization activity were found to be 4% glucose and 1% yeast extract, respectively. The best amino acid source reported was 0.3 mg/ml glutamine. At a temperature of 300C and pH 7.0, the organism showed maximum biodedulfurization activity.