Moreover, there was no lag of biodegradation for both ethylbenzene and p-xylene, i.e., biodegradation started as soon as the pollutants came in contact with the cells. In contrast, toluene exhibited a biodegradation lag of about 80 h, followed by complete removal after 400 h of contact with the immobilized Mycobacterium sp. CHXY119 at an average biodegradation rate of 0.087 mg l−1 h−1. Immobilized Mycobacterium sp. CHXY119 had the worst efficiency for removing benzene, which is the most serious threat to human health among the BTEX compounds and has a minimum permitted dose of 0.005 mg l−1 in drinking water.