Anaerobic biodegradation of benzene series compounds by mixed culturesbased on optional electronic acceptors
HU Zhi-feng , DOU Jun-feng , LIU Xiang , ZHENG Xi-lai , DENG Dong
DOI:
Received November 29, 2006,Revised January 29, 2007, Accepted , Available online
Volume 19,2007,Pages 1049-1054
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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 > pxylene.
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.
