IMDEA Energy Institute, Biotechnological Processes Unit, 28935, Móstoles, Spain.
Leibniz Institute for Agricultural Engineering and Bioeconomy e.V. (ATB), 14469, Potsdam, Germany.
J Biotechnol. 2020 Nov 10;323:9-16. doi: 10.1016/j.jbiotec.2020.07.017. Epub 2020 Jul 24.
Cellulose valorisation has been successfully addressed for years. However, the use of hemicellulosic hydrolysates is limited due to the presence of C5-sugars and inhibitors formed during pretreatment. Bacillus coagulans is one of the few bacteria able to utilize both C6- and C5-sugars to produce l-lactic acid, but its susceptibility to the lignocellulosic inhibitors needs further investigation. For such a purpose, the tolerance of different B. coagulans strains to increasing concentrations of inhibitors is studied. The isolated A162 strain reached the highest l-lactic acid productivity in all cases (up to 2.4 g L h), even in presence of 5 g L of furans and phenols. Remarkably, most of furans and phenolic aldehydes were removed from defined media and hemicellulosic gardening hydrolysate after fermentation with A162. Considering the high productivities and the biodetoxifying effect attained, A162 could be pointed out as a great candidate for valorisation of mixed sugars from hemicellulosic hydrolysates with high inhibitors concentration, promoting the implementation of lignocellulosic biorefineries.
多年来，纤维素的增值利用问题已得到成功解决。然而，由于预处理过程中形成的 C5 糖和抑制剂的存在，半纤维素水解物的应用受到限制。凝结芽孢杆菌是少数能够同时利用 C6 糖和 C5 糖生产 l-乳酸的细菌之一，但它对木质纤维素抑制剂的敏感性仍需进一步研究。为此，研究了不同凝结芽孢杆菌菌株对不断增加的抑制剂浓度的耐受能力。在所有情况下（甚至在存在 5 g/L 呋喃和酚类物质的情况下），分离出的 A162 菌株的 l-乳酸生产力最高（最高可达 2.4 g/L/h）。值得注意的是，A162 在发酵后可以从定义良好的培养基和木质纤维素园艺水解物中去除大部分呋喃和酚醛类物质。考虑到高生产力和生物解毒效果，A162 可以作为从木质纤维素水解物中利用高抑制剂浓度混合糖的有前途的候选物，促进木质纤维素生物炼制厂的实施。
