Anaerobic co-metabolic oxidation of 4-alkylphenols with medium-length or long alkyl chains by Thauera sp., strain R5
Anaerobic co-metabolic oxidation of 4-alkylphenols with medium-length or long alkyl chains by Thauera sp., strain R5
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DOI：
10.1007/s00253-007-0918-8
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发表时间：
2007-03
影响因子：
5
通讯作者：
A. Shibata;A. Katayama
中科院分区：
文献类型：
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作者：
A. Shibata;A. Katayama
以4-正丙基苯酚、4-正丁基苯酚和4-羟基苯甲酸（4-HBA）为富集剂，在硝酸盐还原条件下，从水稻土中分离到一株4-烷基苯酚降解兼性厌氧细菌R5。菌株R5是一株革兰氏阴性杆菌，生长在具有短烷基链（≤C2）的酚类化合物、有机酸和乙醇上。16 S核糖体RNA基因序列分析表明该菌株属于Thauerasp。在4-HBA为碳源的条件下，该菌株将中长链（C3-C8）的4-正烷基酚转化为相应的氧化产物：1-（4-羟基苯基）-1-烯烃、-（4-羟基苯基）-1-烷酮和/或1-（4-羟基苯基）-1-醇。该菌株还将4-异丙基苯酚和4-仲丁基苯酚转化为（4-羟基苯基）-异丙烯和（4-羟基苯基）-仲丁烯，但不转化为具有叔烷基链的4-烷基苯酚（4-叔丁基苯酚或4-叔辛基苯酚）。没有另一种碳源，生物转化不会进行，并与硝酸盐还原相结合。以对甲酚、4-乙基苯酚、4′-羟基苯乙酮和4-HBA为碳源时，该菌株的转化活性较高，而以有机酸和乙醇为碳源时，该菌株的转化活性较低。我们建议，菌株R5共代谢转化烷基酚与氧化的α碳在烷基链中的相应的代谢产物在耦合与硝酸盐还原。
A 4-alkylphenol-degrading facultative anaerobic bacterium, strain R5, was isolated from paddy soil after enrichment with 4-n-propylphenol, 4-n-butylphenol and 4-hydroxybenzoate (4-HBA) under nitrate-reducing conditions. Strain R5 is a Gram-negative rod bacillus grown on phenolic compounds with short alkyl chains (≤C2), organic acids and ethanol. The sequence of the 16S ribosomal RNA gene revealed that the strain is affiliated withThauerasp. In the presence of 4-HBA as a carbon source, the strain transformed 4-n-alkylphenols with a medium or long-length alkyl chain (C3–C8) to the corresponding oxidised products as follows: 1-(4-hydroxyphenyl)-1-alkenes, -(4-hydroxyphenyl)-1-alkanones and/or 1-(4-hydroxyphenyl)-1-alcohols. The strain also transformed 4-i-propylphenol and 4-sec-butylphenol to (4-hydroxyphenyl)-i-propene and (4-hydroxyphenyl)-sec-butene but not 4-alkylphenols with tertiary alkyl chains (4-t-butylphenol or 4-t-octylphenol). The biotransformation did not proceed without another carbon source and was coupled with nitrate reduction. Biotransformation activity was high in the presence ofp-cresol, 4-ethylphenol, 4′-hydroxyacetophenone and 4-HBA as carbon sources and low in the presence of organic acids and ethanol. We suggest that strain R5 co-metabolically transforms alkylphenols to the corresponding metabolites with oxidised alpha carbon in the alkyl chain during coupling with nitrate reduction.