Yang Mengdan, Wei Tiandi, Wang Kai, Jiang Liqun, Zeng Dihao, Sun Xinhua, Liu Weifeng, Shen Yu
State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao, 266237, China.
Guangdong Engineering Laboratory of Biomass High-Value Utilization, Guangzhou Key Laboratory of Biomass Comprehensive Utilization, Guangdong Plant Fiber Comprehensive Utilization Engineering Technology Research and Development Center, Institute of Biological and Medical Engineering, Guangdong Academy of Sciences, Guangzhou, 510640, China.
Biotechnol Biofuels Bioprod. 2022 Sep 14;15(1):94. doi: 10.1186/s13068-022-02195-x.
Manufacturing fuels and chemicals from cellulose materials is a promising strategy to achieve carbon neutralization goals. In addition to the commonly used enzymatic hydrolysis by cellulase, rapid pyrolysis is another way to degrade cellulose. The sugar obtained by fast pyrolysis is not glucose, but rather its isomer, levoglucosan (LG). Here, we revealed that both levoglucosan kinase activity and the transportation of levoglucosan are bottlenecks for LG utilization in Saccharomyces cerevisiae, a widely used cell factory. We revealed that among six heterologous proteins that had levoglucosan kinase activity, the 1,6-anhydro-N-acetylmuramic acid kinase from Rhodotorula toruloides was the best choice to construct levoglucosan-utilizing S. cerevisiae strain. Furthermore, we revealed that the amino acid residue Q341 and W455, which were located in the middle of the transport channel closer to the exit, are the sterically hindered barrier to levoglucosan transportation in Gal2p, a hexose transporter. The engineered yeast strain expressing the genes encoding the 1,6-anhydro-N-acetylmuramic acid kinase from R. toruloides and transporter mutant Gal2p or Gal2p consumed ~ 4.2 g L LG in 48 h, which is the fastest LG-utilizing S. cerevisiae strain to date.
从纤维素材料制造燃料和化学品是实现碳中和目标的一项有前景的策略。除了常用的纤维素酶酶促水解外，快速热解是另一种降解纤维素的方法。通过快速热解获得的糖不是葡萄糖，而是其异构体左旋葡萄糖（LG）。在此，我们揭示了左旋葡萄糖激酶活性和左旋葡萄糖的转运都是酿酒酵母（一种广泛使用的细胞工厂）中利用LG的瓶颈。我们发现，在具有左旋葡萄糖激酶活性的六种异源蛋白中，来自红酵母的1,6-脱水-N-乙酰胞壁酸激酶是构建利用左旋葡萄糖的酿酒酵母菌株的最佳选择。此外，我们还发现，位于靠近出口的转运通道中部的氨基酸残基Q341和W455是己糖转运蛋白Gal2p中左旋葡萄糖转运的空间位阻屏障。表达来自红酵母的1,6-脱水-N-乙酰胞壁酸激酶基因和转运蛋白突变体Gal2p或Gal2p的工程酵母菌株在48小时内消耗了约4.2 g/L的LG，这是迄今为止利用LG最快的酿酒酵母菌株。
