Characterization of a strain catalyzing biosynthesis of 3-hydroxypropionic acid

Abstract

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/18S 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.