State Key Laboratory of Biocatalysis and Enzyme Engineering, and School of Life Sciences, Hubei University, Wuhan 430062, China.
ACS Synth Biol. 2023 Apr 21;12(4):1297-1307. doi: 10.1021/acssynbio.3c00056. Epub 2023 Apr 10.
Molasses with abundant sugars is widely used for bioethanol production. Although the ethanologenic bacterium can use glucose, fructose, and sucrose for ethanol production, levan production from sucrose reduces the ethanol yield of molasses fermentation. To increase ethanol production from sucrose-rich molasses, was adapted in molasses, sucrose, and fructose in parallel. Adaptation in fructose is the most effective route to generate an evolved strain F74 with improved molasses utilization, which is majorly due to a G99S mutation in Glf for enhanced fructose import. Subsequent deletion and overexpression in F74 to divert sucrose metabolism from levan production to ethanol production further enhanced ethanol productivity 28.6% to 1.35 g/L/h. The efficient utilization of molasses by diverting sucrose metabolic flux through adaptation and genome engineering not only generated an excellent ethanol producer using molasses but also provided the strategy for developing microbial cell factories.
富含糖分的糖蜜被广泛用于生物乙醇生产。虽然产乙醇菌可以利用葡萄糖、果糖和蔗糖进行乙醇生产，但蔗糖转化为密二糖会降低糖蜜发酵的乙醇产量。为了提高富含蔗糖的糖蜜的乙醇产量，我们同时对糖蜜、蔗糖和果糖中的进行了适应性进化。果糖适应性进化是产生改良糖蜜利用的进化菌株 F74 的最有效途径，这主要归因于 Glf 中的 G99S 突变，从而增强了果糖的导入。随后在 F74 中删除和过表达，将蔗糖代谢从密二糖生产转向乙醇生产，进一步将乙醇生产率提高了 28.6%，达到 1.35 g/L/h。通过适应性进化和基因组工程将蔗糖代谢通量转向，实现了糖蜜的高效利用，不仅为利用糖蜜生产乙醇提供了优秀的生产菌，也为开发微生物细胞工厂提供了策略。
