全细胞生物催化合成(R)-2-羟基-4-苯基 丁酸乙酯

Whole Cell Catalytic Synthesis of Ethyl (R)-2-hydroxy-4-ethylbutyrate

摘要:

利用全细胞生物催化合成(R)-2-羟基-4-苯基丁酸乙酯[(R)-HPBE]，并利用氢核磁共振（1HNMR）、气相色谱-质谱联用(GC-MS)、液相色谱(LC)对产物结构进行表征。以2-羰基-4-苯基丁酸乙酯（OPBE）为唯一碳源，从葡萄园土壤中筛选分离得到一株高选择性不对称还原OPBE为(R)-HPBE的菌株酵母G5，通过形态和18S rDNA分析鉴定为粘质红酵母(Rhodotorula mucilaginosa CCZU- G5)。构建Rhodotorula mucilaginosa CCZU- G5全细胞催化还原OPBE合成(R)-HPBE的反应体系并进行了优化。结果表明最适催化反应条件为：在20 mL PBS反应体系中，反应温度为35 ℃，pH 7.5，菌体质量浓度0.2 g/mL，葡萄糖质量浓度3.0%，金属离子Ca2+ 浓度3 mmol/L，底物OPBE浓度为20 mmol/L，反应时间12 h，(R)-HPBE产率达82%，对映体过量值(e.e.)值为99.9%。

Abstract:

A strain of Yeast G5 was isolated from vineyard soil samples, which can catalyze asymmetric reduction of ethyl-2-oxo-4-phenylbutanoate (OPBE) to ethyl (R)-2-hydroxy-4-phenylbutyrate [(R)-HPBE]. It was identified as Rhodotorula mucilaginosa by its morphological and 18S rDNA sequence analysis. Various parameters affecting on asymmetric biocatalytic reduction of Rhodotorula mucilaginosa CCZU-G5 were investigated, and the optimal conditions were achieved, i.e. 35 ℃, pH 7.0, cell concentration 0.2 g/mL, 3.0% glucose (w/v), 3 mmol/L Ca2 . After reacting 12 h under the optimum conditions, the product yield would be up to 82% with 99.9% e.e. value.