ABSTRACT
Rhodococcus sp. 2N was found as a 1,3-propanediols-oxidizing strain from soil samples through enrichment culture using 2,2-diethyl-1,3-propanediol (DEPD) as the sole carbon source. The culture condition of the strain 2N was optimized, and the highest activity was observed when 0.3% (w/v) DEPD was added in the culture medium as an inducer. Chiral HPLC analysis of the hydroxyalkanoic acid converted from 2-ethyl-2-methyl-1,3-propanediol (EMPD) revealed that the strain 2N catalyzed the (R)-selective oxidation of EMPD. The reaction products and intermediates from DEPD and EMPD were identified by nuclear magnetic resonance analyses, and the results suggested that only one hydroxymethyl group of the propanediols was converted to carboxy group via two oxidation steps. Under optimized conditions and after a 72-h reaction time, the strain 2N produced 28 mM (4.1 g/L) of 2-(hydroxymethyl)-2-methylbutanoic acid from EMPD with a molar conversion yield of 47% and 65% ee (R).
摘要:从土壤样品中通过富集培养发现了Rhodococcus sp. 2N作为一株氧化1,3-丙二醇的菌株,其使用2,2-二乙基-1,3-丙二醇(DEPD)作为唯一碳源。优化了菌株2N的培养条件,当将0.3%(w/v)的DEPD作为诱导剂添加到培养基中时,观察到最高的活性。通过手性高效液相色谱分析从2-乙基-2-甲基-1,3-丙二醇(EMPD)转化而来的羟基烷酸,发现菌株2N催化了EMPD的(R)-选择性氧化。通过核磁共振分析鉴定了来自DEPD和EMPD的反应产物和中间体,结果表明丙二醇的一个羟甲基通过两步氧化转化为羧基。在优化条件下,经过72小时反应时间,菌株2N从EMPD产生了28毫摩尔(4.1克/升)的2-(羟甲基)-2-甲基丁酸,摩尔转化产率为47%,ee(R)为65%。