Potential of Bacillus subtilis from marine environment to degrade aromatic hydrocarbons

Abstract

Microbial degradation of aromatic pollutants has been a promising method for bioremediation and restoring environmental damage. Protocatechuate (PCA) is a common intermediate in the microbial degradation of several aromatic compounds. The present study reports the identification of protocatechuate 3,4-dioxygenase (3,4-PCD)—a key enzyme of the β-ketoadipate pathway, in Bacillus subtilis isolated from coastal water containing waste discharge from paper mills, textile industries, and timber processing factories. The strain efficiently degraded PCA up to 20 mM concentration. Enzyme assay indicated the production of 3,4-PCD and cleavage of the benzene ring at ortho position and the formation of keto compounds of the beta- ketoadipate pathway. The utilization of PCA by plasmid cured cells indicates PCA metabolism is encoded by chromosomal genes. The metabolic potential of the B. subtilis isolate makes it a promising tool for bioremediation of aromatic pollutants present in marine environments.