ANAEROBIC TOLUENE MINERALIZATION PATHWAY IN AZOARCUS TOLULYTICUS SP TOL 4

甲苯降解菌A.甲苯溶菌Tol-4， 从3份石油污染的样品中分离出8株相似菌株， 含水层沉积物 当菌株在甲苯上厌氧生长时， 甲苯中68%的碳以二氧化碳的形式存在， 发现生物质。 因为这种微生物是专性厌氧菌， 必须有一个新的途径降解甲苯。 苯甲酸 似乎是途径中的中间体，因为氟代苯甲酸酯 当将氟甲苯添加到生长培养基中时， 在 此外，[14 C]苯甲酸酯是在[14 C]甲苯存在下由[14 C]甲苯制备的。 过量的苯甲酸 两种代谢产物，E-苯亚硝酸（1 - 2%） 和苄基琥珀酸（<1%），从厌氧甲苯中积累 新陈代谢. 这些相同的产物也是在细胞 生长在氢化肉桂酸和反式肉桂酸上，但不 由苯甲醇、苯甲醛、苯甲酸、对甲酚或 它们的羟基化类似物。 有证据表明 甲苯降解途径涉及初始乙酰辅酶A攻击， 菌株Tol-4。 我们认为肉桂酰辅酶A 遵循氢化肉桂酰辅酶A的氧化，类似于推测的 氧化苄基琥珀酸形成E-苯基亚硝酸。 我们 我建议制备一些用碳-13标记的中间体 并通过碳-13核磁共振光谱跟踪它们的代谢。

A toluene degrading denitrifier bacterium, A. tolulyticus Tol-4, was I of 8 similar strains isolated from 3 petroleum-contaminated aquifer sediments. When the strain is grown anaerobically on toluene, 68% of the carbon from toluene is found as carbondioxide and 30% is found as biomass. Because this organism is an obligate anaerobe, it must have a novel pathway for biodegradation of toluene. Benzoic acid appears to be an intermediate in the pathway, because fluoro-benzoate accumulated when fluorotoluene was added to the growth medium. In addition, [14C]benzoate was produced from [14C]toluene in the presence of excess benzoate. Two metabolites, E-phenylitaconic acid (1 -2%) and benzy1succinic acid (<1%), accumulated from anaerobic toluene metabolism. These same products were also produced when cells were grown on hydrocinnamic acid and trans-cinnamic acid but were not produced from benzyl alcohol, benzaldehyde, benzoic acid, p-cresol, or their hydroxylated analogs. The evidence supports an anaerobic toluene degradation pathway involving an initial acetyl-CoA attack in strain Tol-4. We propose that a pathway in which cinnamoyl-CoA follows the oxidation of hydrocinnamoyl-CoA, analogous to the presumed oxidation of benzy1succinic acid to form E-phenylitaconic acid. We propose to prepare some of thes intermediates labeled with carbon- 13 and follow their metabolism by carbon- 13 NMR spectroscopy.