Zhang Biao, Ren Lili, Zeng Shuai, Zhang Siyang, Xu Dayong, Zeng Xin, Li Feng
Anhui Province Key Laboratory of Pollutant Sensitive Materials and Environmental Remediation, School of Life Sciences, Huaibei Normal University, Huaibei, Anhui, 235000, People's Republic of China.
Appl Microbiol Biotechnol. 2020 Sep;104(18):7991-8006. doi: 10.1007/s00253-020-10808-4. Epub 2020 Aug 10.
Glycolysis and the pentose phosphate pathway (PPP) are two basic metabolic pathways that are simultaneously present in yeasts. As the main pathway in most species, the glycolysis provides ATP and NADH for cell metabolism while PPP, as a complementary pathway, supplies NADPH. In this study, the performance of Kluyveromyces marxianus using glycolysis or PPP were studied through the disruption of PGI1 or ZWF1 gene, respectively. K. marxianus using glycolysis as the only pathway showed higher ethanol production ability than that of the Kluyveromyces lactis zwf1Δ mutant; K. marxianus using only PPP showed more robustness than that of Saccharomyces cerevisiae pgi1Δ mutant. Additionally, K. marxianus pgi1Δ strain accumulated much more intracellular NADPH than the wild type strain and co-utilized glucose and xylose more effectively. These findings suggest that phosphoglucose isomerase participates in the regulation of the repression of glucose on xylose utilization in K. marxianus. The NADPH/NADP ratio, dependent on the activity of the PPP, regulated the expression of multiple genes related to NADPH metabolism in K. marxianus (including NDE1, NDE2, GLR1, and GDP1). Since K. marxianus is considered a promising host in industrial biotechnology to produce renewable chemicals from plant biomass feedstocks, our research showed the potential of the thermotolerant K. marxianus to produce NADP(H)-dependent chemical synthesis from multiple feedstocks. KEY POINTS: • The function of PGI1 and ZWF1 in K. marxianus has been analyzed in this study. • K. marxianus zwf1Δ strain produced ethanol but with decreased productivity. • K. marxianus pgi1Δ strain grew with glucose and accumulated NADPH. • K. marxianus pgi1Δ strain released glucose repression on xylose utilization.
糖酵解和磷酸戊糖途径（PPP）是酵母中同时存在的两条基本代谢途径。作为大多数物种的主要途径，糖酵解为细胞代谢提供ATP和NADH，而PPP作为一条补充途径，提供NADPH。在本研究中，分别通过破坏PGI1或ZWF1基因，研究了马克斯克鲁维酵母利用糖酵解或PPP的性能。仅将糖酵解作为唯一途径的马克斯克鲁维酵母比乳酸克鲁维酵母zwf1Δ突变体具有更高的乙醇生产能力；仅使用PPP的马克斯克鲁维酵母比酿酒酵母pgi1Δ突变体表现出更强的稳健性。此外，马克斯克鲁维酵母pgi1Δ菌株比野生型菌株积累了更多的细胞内NADPH，并且能更有效地共同利用葡萄糖和木糖。这些发现表明，磷酸葡萄糖异构酶参与了马克斯克鲁维酵母中葡萄糖对木糖利用的阻遏调控。依赖于PPP活性的NADPH/NADP比值，调节了马克斯克鲁维酵母中多个与NADPH代谢相关基因（包括NDE1、NDE2、GLR1和GDP1）的表达。由于马克斯克鲁维酵母被认为是工业生物技术中从植物生物质原料生产可再生化学品的有前景的宿主，我们的研究显示了耐热性马克斯克鲁维酵母从多种原料生产NADP（H）依赖性化学合成物的潜力。要点：• 本研究分析了PGI1和ZWF1在马克斯克鲁维酵母中的功能。• 马克斯克鲁维酵母zwf1Δ菌株产生乙醇，但生产力下降。• 马克斯克鲁维酵母pgi1Δ菌株利用葡萄糖生长并积累NADPH。• 马克斯克鲁维酵母pgi1Δ菌株解除了葡萄糖对木糖利用的阻遏。
