School of Bioengineering, Dalian University of Technology, No.2 Linggong Road, Ganjingzi District, Dalian City, Liaoning Province, 116024, People's Republic of China.
Bioprocess Biosyst Eng. 2021 Sep;44(9):1935-1941. doi: 10.1007/s00449-021-02573-z. Epub 2021 Apr 22.
The purpose of this study was to establish a simplified operational process for lactic acid (LA) production from inedible starchy biomass by open fermentation using thermotolerant Lactobacillus rhamnosus DUT1908. One step simultaneous liquefaction, saccharification and fermentation (SLSF) was proposed to produce LA using aging paddy rice with hull (APRH) as feedstock. First, a robust microbial strain was obtained by adaptive laboratory evolution under high temperature stress. As a result, L. rhamnosus DUT1908 showed high thermotolerance up to 50 °C and high efficiency of substrate utilization. Then, the performance of this thermotolerant L-lactic acid producing strain was demonstrated. Finally, various fermentation strategies were compared for LA production from APRH, including simultaneous saccharification and fermentation (SSF) and SLSF. In one-step open SLSF process, 107.8 g/L lactic acid was obtained with a productivity of 3.4 g/(L.h) and a yield to theoretical glucose of 0.89 g/g. This is the highest yield and productivity of lactic acid reported on starchy residues, and provides an efficient route for the development of high value-added products.
本研究旨在建立一种使用耐热乳杆菌 DUT1908 通过开放式发酵从不可食用的淀粉生物质生产乳酸 (LA) 的简化操作流程。提出了一步同步液化、糖化和发酵（SLSF）方法，以老化带壳稻谷（APRH）为原料生产 LA。首先，通过高温胁迫下的适应性实验室进化获得了一种稳健的微生物菌株。结果，L. rhamnosus DUT1908 表现出高达 50°C 的高热耐受性和高效的基质利用效率。然后，展示了这种耐热 L-乳酸生产菌株的性能。最后，比较了各种发酵策略从 APRH 生产 LA，包括同步糖化和发酵（SSF）和 SLSF。在一步开放式 SLSF 工艺中，获得了 107.8 g/L 的乳酸，产率为 3.4 g/（L.h），理论葡萄糖产率为 0.89 g/g。这是淀粉残渣中报道的最高乳酸产率和生产率，为开发高附加值产品提供了有效的途径。
