Gibson S A, Suflita J M
Department of Botany and Microbiology, University of Oklahoma, Norman 73019-0245.
Biodegradation. 1993;4(1):51-7. doi: 10.1007/BF00701454.
A bacterial consortium that anaerobically mineralized phenoxyacetate, with transient production of phenol as an intermediate, was obtained from a methanogenic aquifer site near the Norman, OK municipal landfill. This consortium was able to convert the eight halogenated chlorophenoxyacetates tested to the corresponding chlorophenols. The chlorophenols were not subsequently metabolized. The addition of reduced substrates increased the rate of degradation of all chlorophenoxyacetates, with 78% of mono- and di-chlorinated substrates being transformed to chlorophenols in butyrate-amended cultures, compared to less than 37% transformed in unsupplemented cultures. Butyrate increased the transformation of 2,4,5-trichlorophenoxyacetate from 10% to 20%. An experiment evaluating the effects of several compounds on the side-chain cleavage reaction of 3-chlorophenoxyacetate showed that addition of compounds which readily act as hydrogen donors (butyrate, crotonate, ethanol, propionate, and hydrogen) resulted in 2 to 5 times the amount of 3-chlorophenoxyacetate transformed compared to controls with no amendment, formate had a slight stimulatory effect, and acetate and methanol had no effect. Butyrate addition also increased the rate of phenoxyacetate degradation, resulting in transient phenol accumulation not observed in butyrate-unamended controls. These results support the hypothesis that the side-chain cleavage of phenoxyacetate is a reductive process that is stimulated by the oxidation of reduced cosubstrates.
从俄克拉何马州诺曼市城市垃圾填埋场附近的产甲烷含水层场地获得了一个细菌群落，该群落能在厌氧条件下将苯氧乙酸矿化，并以苯酚作为中间产物短暂生成。这个群落能够将所测试的8种卤代氯苯氧乙酸转化为相应的氯酚。氯酚随后未被进一步代谢。添加还原型底物提高了所有氯苯氧乙酸的降解速率，在添加丁酸盐的培养物中，78%的单氯和二氯底物转化为氯酚，而在未添加底物的培养物中这一比例不到37%。丁酸盐使2,4,5-三氯苯氧乙酸的转化率从10%提高到20%。一项评估几种化合物对3-氯苯氧乙酸侧链裂解反应影响的实验表明，添加易于作为氢供体的化合物（丁酸盐、巴豆酸盐、乙醇、丙酸盐和氢气）导致3-氯苯氧乙酸的转化量是未添加对照的2至5倍，甲酸盐有轻微的刺激作用，而乙酸盐和甲醇没有作用。添加丁酸盐还提高了苯氧乙酸的降解速率，导致在未添加丁酸盐的对照中未观察到的短暂苯酚积累。这些结果支持了以下假设：苯氧乙酸的侧链裂解是一个还原过程，受还原型共底物的氧化作用刺激。
