Evaluation of organosulfur compound degradation property of a noble bacterial strain of Proteus mirabilis

Abstract

Organosulfur compounds asssociated with coal are the major contributors to environmental pollution. An organosulfur compound dibenzothiophene (DBT) occupies about 70% of all the organosulfur compounds detected in coal. Microbial desulfurization processes are evolving as a tool for the remediation of organosulfur compounds. The present work deals with a microbial processing technique developed for the degradation of an organosulfur compound DBT by a noble bacterial strain Proteus mirabilis isolated from petroleum-contaminated soil. The study revealed that the bacterium has a high tolerance towards higher concentrations of DBT and performed a normal rate of bacterial growth in a culture medium supplemented with 50 mM of DBT. The Proteus mirabilis bacterium catalyzed the microbial desulfurization of DBT present in the culture medium. It was estimated that the bacterium desulfurized about 99% of the DBT incubated in 500 mL of culture medium at 37 °C ± 2 with the Proteus mirabilis for 5 days. The high-performance liquid chromatography (HPLC) analysis showed the presence of 2-hydroxybiphenyl in the bacterial culture medium indicating that the bacterium has followed a sulfur-specific 4S microbial pathway for the degradation of DBT through the production of 2-hydroxybiphenyl.