Abstract：
Thermo-acidic pretreatment of lignocellulosic biomass is required to make it amenable to microbial metabolism and results in generation of furfural due to breakdown of pentose sugars. Furfural is toxic to microbial metabolism and results in reduced microbial productivity and increased production costs. This study asks if deletion of yghZ gene which encodes a NADPH-dependent aldehyde reductase enzyme results in improved furfural tolerance in Escherichia coli host. The ∆yghZ strain-SSK201-was tested for tolerance to furfural in presence of 5% xylose as a carbon source in AM1 minimal medium. At 96 h and in presence of 1.0 g/L furfural, the culture harboring strain SSK201 displayed 4.5-fold higher biomass, 2-fold lower furfural concentration and 15.75-fold higher specific growth rate (µ) as compared to the parent strain SSK42. The furfural tolerance advantage of SSK201 was retained when the carbon source was switched to glucose in AM1 medium and was lost in rich LB medium. The findings have potential to be scaled up to a hydrolysate culture medium, which contains furan inhibitors and lack nutritionally rich components, under bioreactor cultivation and observe growth advantage of the ∆yghZ host. It harbors potential to generate robust industrial strains which can convert lignocellulosic carbon into metabolites of interest in a cost-efficient manner.
摘要：
需要对木质纤维素生物质进行热酸性预处理以使其适合微生物代谢并由于戊糖的分解而导致糠醛的产生。糠醛对微生物代谢是有毒的并且导致降低的微生物生产率和增加的生产成本。这项研究询问编码NADPH依赖性醛还原酶的yghZ基因的缺失是否会导致大肠杆菌宿主中糠醛耐受性的提高。在AM1基本培养基中，在5％木糖作为碳源的存在下，测试了ΔyghZ菌株-SSK201-对糠醛的耐受性。在96小时和1.0g/L糠醛存在下，培养菌株SSK201表现出4.5倍的生物量，与亲本菌株SSK42相比，糠醛浓度低2倍，比生长速率（µ）高15.75倍。当在AM1培养基中将碳源转换为葡萄糖时，SSK201的糠醛耐受性优势得以保留，而在富LB培养基中丢失。这些发现有可能扩大到水解产物培养基，其中含有呋喃抑制剂，缺乏营养丰富的成分，在生物反应器培养下，观察ΔyghZ宿主的生长优势。它具有产生强大的工业菌株的潜力，这些菌株可以以具有成本效益的方式将木质纤维素碳转化为感兴趣的代谢物。
