高效催化合成3-羟基丙酸的菌株特性

Characterization of a strain catalyzing biosynthesis of 3-hydroxypropionic acid

3-羟基丙酸(3-HP)是一种具有重要经济价值的新兴平台化合物,可用来合成多种化工产品和特种生物降解材料.本研究以1,3-丙二醇(1,3-PDO)为底物全细胞催化合成3-HP.通过菌株筛选和ESI-MS验证共得到3株目的微生物,经鉴定比较,Acetobacter sp.催化合成3-HP性能最高,10 g L-1 1,3-PDO经7 h可生成11.65 g L-1的3-HP,摩尔转化率高达98.4%.对Acetobacter sp.底物催化特异性研究表明该菌株对其他相关醇类如乙二醇、戊醇、苯甲醇、苯乙醇等具有不同程度的催化能力,Acetobacter sp.对甘油仅具有微弱催化活性.研究表明Ca2+、Mg2+、Fe3+能够显著提高细胞催化合成3-HP的速率,向全细胞催化液中加入终浓度0.01 mol L-1的CaCl2,细胞催化活性提高了11.6%.同时考察了氧载体和表面活性剂、贮存温度、菌体重复利用对Acetobacter sp.催化活性的影响并获得了该菌株催化合成3-HP的特性.利用Acetobacter sp.细胞催化1,3-PDO,为3-HP的制备提供了一种新的可能.

3-hydroxypropionic acid（3-HP） is one of the strategic building blocks with highly-economic value. This study aimed to screen microbial strains catalyzing 1,3-propanediol（1,3-PDO） to 3-HP, and to understand their catalytic properties. The strains were isolated through transparent circle method, and identified by morphological analysis, biochemical properties and 16S/18 S rDNA gene sequences. The products were confirmed by HPLC and ESI-MS. The catalytic activity of the target strain was represented by the average 3-HP production rate in 6 h. Three different strains were screened, among them strain Acetobacter sp. with the best catalytic performance was used as biocatalyst in the subsequent experiments. After 7 h biocatalysis, 11.65 g L-1 3-HP was obtained with a high molar conversion（98.4%）. Acetobacter sp. catalytic specificity showed that the strain could also catalyze ethylene glycol, amyl alcohol, benzyl alcohol, phenylethyl alcohol to a certain extent, but having weak catalytic activity on glycerol. It was founded that Ca2＋, Mg2＋, Fe3＋ could significantly improve 3-HP production rate, Acetobacter sp. catalytic activity increased 11.6% when 0.01 mol L-1 CaCl2 was added to the biocatalytic system. Factors including oxygen carriers and surface active agents, storage temperature and cell reusability also influenced the catalytic activity of Acetobacter sp. To the best of our knowledge, this is the first report describing the production of 3-HP from 1,3-PDO by Acetobacter strains. The biocatalysis procedure introduced in this study can provide an economically and technically promising alternative for 3-HP production.