[1S02a] 02. AFOB - Part 2

3:35 PM - 3:45 PM JST(6:35 AM - 6:45 AM UTC)

[1AFOB-14] Engineering Microbial Cell Factories for Lignocellulose Bioconversion

○Kai Li¹ (1. Shanghai Jiao Tong University (China))

Keywords:

Synthetic biology,Lignocellulose,Cell factory,Cellulase,α-Carotene

Effective utilization of glucose, xylose, and acetate, common carbon sources in lignocellulose hydrolysate, can boost biomanufacturing economics. However, carbon leaks into biomass biosynthesis pathways instead of the intended target product remain to be optimized. This study aimed to enhance a carotene production by optimizing glucose, xylose, and acetate utilization in a high efficiency Corynebacterium glutamicum cell factory. Heterologous xylose pathway expression in C. glutamicum resulted in strain m4, exhibiting a threefold increase in a carotene production from xylose compared to glucose. Xylose utilization was found to boost the biosynthesis of pyruvate and acetyl CoA, essential precursors for carotenoid biosynthesis. Additionally, metabolic engineering including pck, pyc, ppc, and aceE deletion, completely disrupted the metabolic connection between glycolysis and the TCA cycle, further enhancing a carotene production. This strategic intervention directed glucose and xylose primarily towards target chemical production, while acetate supplied essential metabolites for cell growth recovery. The engineered strain C. glutamicum m8 achieved 30 mg/g a carotene, 67% higher than strain m4. In fed batch fermentation, strain m8 produced 1,802 mg/L of a carotene, marking the highest titer reported to date in microbial fermentation. Moreover, it exhibited excellent performance in authentic lignocellulosic hydrolysate, producing 216 mg/L a carotene, 1.75 times higher than the initial strain m4. This labor division strategies significantly contribute to the development of clean processes for producing various valuable chemicals from lignocellulosic biomass.