A novel BTEX degrading strain isolated from contaminated groundwater was evaluated. Response surface methodology was used to determine the effective parameters in BTEX biodegradation. Pseudomonas sp. BTEX-30 was able to degrade a mixture of BTEX compounds in water phase. m-Xylene co-metabolized in the presence of benzene and toluene Dioxygenase was found to be the key incorporating enzyme in co-metabolism of m-xylene