Formulation of microbial cocktails for BTEX biodegradation

BTEX biodegradation by a mixed community of micro-organisms offers a promising approach in terms of cost-effectiveness and elimination of secondary pollution. Two bacterial strains, Pseudomonas putida F1 and Pseudomonas stutzeri OX1 were chosen to formulate synthetic consortia based on their ability to biodegrade the mono-aromatic compounds. Benzene and toluene supported the growth of both the strains; while ethyl benzene and o-xylene were only utilized as growth substrates by P. putida F1 and P. stutzeri OX1, respectively. In a mixed substrate system, P. putida F1 exhibited incomplete removal of o-xylene while P. stutzeri OX1 displayed cometabolic removal of ethyl benzene with dark coloration of the growth medium. The biodegradation potential of the two Pseudomonas species complemented each other and offered opportunities to explore their performance as a co-culture for enhanced BTEX biodegradation. Several microbial formulations were concocted and their BTEX biodegradation characteristics were evaluated. Mixed culture biodegradation ascertained the advantages of the co-culture over the individual Pseudomonas species. This study also emphasized the significance of inoculum density and species proportion while concocting preselected micro-organisms for enhanced BTEX biodegradation.