Abdel-Rahman Mohamed Ali, Xiao Yaotian, Tashiro Yukihiro, Wang Ying, Zendo Takeshi, Sakai Kenji, Sonomoto Kenji
Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan; Botany and Microbiology Department, Faculty of Science (Boys), Al-Azhar University, Nasr City PN:11884, Cairo, Egypt.
Laboratory of Microbial Technology, Division of Systems Bioengineering, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
J Biosci Bioeng. 2015 Feb;119(2):153-8. doi: 10.1016/j.jbiosc.2014.07.007. Epub 2014 Oct 1.
There has been tremendous growth in the production of optically pure l-lactic acid from lignocellulose-derived sugars. In this study, Enterococcus mundtii QU 25 was used to ferment a glucose/xylose mixture to l-lactic acid. Maintenance of the xylose concentration at greater than 10 g/L achieved homo-lactic acid fermentation and reduced the formation of byproducts. Furthermore, carbon catabolite repression (CCR) was avoided by maintaining the glucose concentration below 25 g/L; therefore, initial concentrations of 25 g/L glucose and 50 g/L xylose were selected. Supplementation with 5 g/L yeast extract enhanced the maximum xylose consumption rate and consequently increased lactic acid production and productivity. Finally, a 129 g/L lactic acid without byproducts was obtained with a maximum lactic acid productivity of 5.60 g/(L·h) in fed-batch fermentation with feeding a glucose/xylose mixture using ammonium hydroxide as the neutralizing agent. These results indicate a potential for lactic acid production from glucose and xylose as the main components of lignocellulosic biomasses.
利用木质纤维素衍生糖生产光学纯L-乳酸的产量有了巨大增长。在本研究中，蒙氏肠球菌QU 25被用于将葡萄糖/木糖混合物发酵成L-乳酸。将木糖浓度维持在高于10 g/L可实现同型乳酸发酵并减少副产物的形成。此外，通过将葡萄糖浓度维持在25 g/L以下避免了碳代谢物阻遏（CCR）；因此，选择了25 g/L葡萄糖和50 g/L木糖的初始浓度。添加5 g/L酵母提取物提高了最大木糖消耗率，从而提高了乳酸产量和生产率。最后，在补料分批发酵中，以氢氧化铵作为中和剂，进料葡萄糖/木糖混合物，获得了129 g/L无副产物的乳酸，最大乳酸生产率为5.60 g/(L·h)。这些结果表明，以葡萄糖和木糖作为木质纤维素生物质的主要成分生产乳酸具有潜力。
