Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China.
J Ind Microbiol Biotechnol. 2013 Jan;40(1):11-20. doi: 10.1007/s10295-012-1199-5. Epub 2012 Sep 27.
In the search for an effective biocatalyst for the reduction of acetophenones with unprotected hydroxy group on the benzene ring, a microorganism, which reduced para-acetylphenol to S-(-)-1-(para-hydroxyphenyl)ethanol under anaerobic conditions, was isolated from soil samples and the 16S rDNA study showed that it was phylogenetically affiliated with species of the genus Rhodococcus and was most similar to Rhodococcus pyridinivorans. Unexpectedly, this strain also hydroxylated para-acetylphenol to give 4-acetylcatechol in presence of oxygen, possessing para-acetylphenol hydroxylase activity. While the reduction of para-acetylphenol had an optimal reaction pH at 7 and a broad optimal temperature range (35-45 °C), the hydroxylation reached the maximum conversion at the pH range of 7-8 and 35 °C. This study identified for the first time a Rhodococcus strain with para-acetylphenol hydroxylase activity, which also contains highly enantioselective carbonyl reductase activity with potential applications for the asymmetric reduction of these less-explored but important ketones such as α-aminoacetophenone, 3'-hydroxyacetophenone and 4'-hydroxyacetophenone. The para-acetylphenol hydroxylase and carbonyl reductase activity are switchable by the reaction conditions.
在寻找一种有效的生物催化剂,用于还原苯环上未保护的羟基的苯乙酮时,从土壤样本中分离出一种微生物,该微生物在厌氧条件下将对乙酰氨基酚还原为 S-(-)-1-(对羟基苯基)乙醇,16S rDNA 研究表明它与红球菌属的物种具有系统发育关系,与红球菌属 pyridinivorans 最为相似。出乎意料的是,该菌株在有氧存在的情况下也将对乙酰氨基酚羟基化为 4-乙酰儿茶酚,具有对乙酰氨基酚羟化酶活性。虽然对乙酰氨基酚的还原在 pH7 时具有最佳反应 pH 值,并且具有较宽的最佳温度范围(35-45°C),但羟基化在 pH7-8 和 35°C 的范围内达到最大转化率。本研究首次鉴定出一种具有对乙酰氨基酚羟化酶活性的红球菌菌株,该菌株还含有高度对映选择性的羰基还原酶活性,可用于不对称还原这些研究较少但很重要的酮,如α-氨基苯乙酮、3'-羟基苯乙酮和 4'-羟基苯乙酮。对乙酰氨基酚羟化酶和羰基还原酶的活性可通过反应条件进行切换。