Be. Haigler et Jc. Spain, BIODEGRADATION OF 4-NITROTOLUENE BY PSEUDOMONAS SP STRAIN 4NT, Applied and environmental microbiology, 59(7), 1993, pp. 2239-2243
A strain of Pseudomonas spp. was isolated from nitrobenzene-contaminat
ed soil on 4-nitrotoluene as the sole source of carbon, nitrogen, and
energy. The organism also grew on 4-nitrobenzyl alcohol, 4-nitrobenzal
dehyde, and 4-nitrobenzoate. 4-Nitrobenzoate and ammonia were detected
in the culture fluid of glucose-grown cells after induction with 4-ni
trotoluene. Washed suspensions of 4-nitrotoluene- or 4-nitrobenzoate-g
rown cells oxidized 4-nitrotoluene, 4-nitrobenzaldehyde, 4-nitrobenzyl
alcohol, and protocatechuate. Extracts from induced cells contained 4
-nitrobenzaldehyde dehydrogenase, 4-nitrobenzyl alcohol dehydrogenase,
and protocatechuate 4,5-dioxygenase activities. Under anaerobic condi
tions, cell extracts converted 4-nitrobenzoate or 4-hydroxylaminobenzo
ate to protocatechuate. Conversion of 4-nitrobenzoate to protocatechua
te required NADPH. These results indicate that 4-nitrotoluene was degr
aded by an initial oxidation of the methyl group to form 4-nitrobenzyl
alcohol, which was converted to 4-nitrobenzoate via 4-nitrobenzaldehy
de. The 4-nitrobenzoate was reduced to 4-hydroxylaminobenzoate, which
was converted to protocatechuate. A protocatechuate 4,5-dioxygenase ca
talyzed meta-ring fission of the protocatechuate. The detection of 4-n
itrobenzaldehyde and 4-nitrobenzyl alcohol dehydrogenase and 4-nitroto
luene oxygenase activities in 4-nitrobenzoate-grown cells suggests tha
t 4-nitrobenzoate is an inducer of the 4-nitrotoluene degradative path
way.