Anaerobic biodegradation of benzene series compounds by mixed cultures based on optional electronic acceptors.
A series of batch experiments were performed using mixed bacterial consortia to investigate biodegradation performance of benzene, toluene, ethylbenzene and three xylene isomers (BTEX) under nitrate, sulfate and ferric iron reducing conditions. The results showed that toluene, ethylbenzene, m-xylene and o-xylene could be degraded independently by the mixed cultures coupled to nitrate, sulfate and ferric iron reduction. Under ferric iron reducing conditions the biodegradation of benzene and p-xylene could be occurred only in the presence of other alkylbenzenes. Alkylbenzenes can serve as the primary substrates to stimulate the transformation of benzene and p-xylene under anaerobic conditions. Benzene and p-xylene are more toxic than toluene and ethylbenzene, under the three terminal electron acceptors conditions, the degradation rates decreased with toluene > ethylbenzene > m-xylene > o-xylene > benzene > p-xylene. Nitrate was a more favorable electron acceptor compared to sulfate and ferric iron. The ratio between sulfate consumed and the loss of benzene, toluene, ethylbenzene, o-xylene, m-xylene, p-xylene was 4.44, 4.51, 4.42, 4.32, 4.37 and 4.23, respectively; the ratio between nitrate consumed and the loss of these substrates was 7.53, 6.24, 6.49, 7.28, 7.81, 7.61, respectively; the ratio between the consumption of ferric iron and the loss of toluene, ethylbenzene, o-xylene, m-xylene was 17.99, 18.04, 18.07, 17.97, respectively.
Hu
Zhi-Feng
ZF
College of Environmental Science and Engineering, Ocean University of China, Qingdao 266003, China. hudu@tom.com
Dou
Jun-Feng
JF
Liu
Xiang
X
Zheng
Xi-Lai
XL
Deng
Dong
D
D000693:Anaerobiosis; D001421:Bacteria, Anaerobic / Q000378:metabolism*; D001554:Benzene / Q000378:metabolism*; D004583:Electrons; D005290:Ferric Compounds / Q000737:chemistry; D009566:Nitrates / Q000737:chemistry; D009573:Nitrites / Q000737:chemistry; D013431:Sulfates / Q000737:chemistry
D005290:Ferric Compounds; D009566:Nitrates; D009573:Nitrites; D013431:Sulfates; D001554:Benzene