Institute of Chemical and Engineering Sciences, Agency for Sciences, Technology and Research, 1 Pesek Road, Jurong Island, Singapore 627833, Singapore.
Bioresour Technol. 2013 Mar;132:38-44. doi: 10.1016/j.biortech.2013.01.011. Epub 2013 Jan 16.
Cost-effective production of optically pure lactic acid from lignocellulose sugars is commercially attractive but challenging. Bacillus coagulans C106 was isolated from environment and used to produce l-lactic acid from xylose at 50°C and pH 6.0 in mineral salts medium containing 1-2% (w/v) of yeast extract without sterilizing the medium before fermentation. In batch fermentation with 85g/L of xylose, lactic acid titer and productivity reached 83.6g/L and 7.5g/Lh, respectively. When fed-batch (120+80+60g/L) fermentation was applied, they reached 215.7g/L and 4.0g/Lh, respectively. In both cases, the lactic acid yield and optical purity reached 95% and 99.6%, respectively. The lactic acid titer and productivity on xylose are the highest among those ever reported. Ca(OH)2 was found to be a better neutralizing agent than NaOH in terms of its giving higher lactic acid titer (1.2-fold) and productivity (1.8-fold) under the same conditions.
从木质纤维素糖中经济高效地生产光学纯乳酸具有商业吸引力，但具有挑战性。凝结芽孢杆菌 C106 是从环境中分离出来的，用于在含有 1-2%（w/v）酵母提取物的无机盐培养基中，在 50°C 和 pH 6.0 下从木糖生产 L-乳酸，发酵前无需对培养基进行灭菌。在 85g/L 木糖的分批发酵中，乳酸的浓度和产率分别达到 83.6g/L 和 7.5g/Lh。当采用补料分批（120+80+60g/L）发酵时，它们分别达到 215.7g/L 和 4.0g/Lh。在这两种情况下，乳酸的产率和光学纯度分别达到 95%和 99.6%。在木糖上的乳酸浓度和产率均高于以往报道的水平。在相同条件下，与 NaOH 相比，Ca(OH)2 作为中和剂可获得更高的乳酸浓度（提高 1.2 倍）和产率（提高 1.8 倍）。
