Engineering of klebsiella oxytoca for sustainable production of 2,3-butanediol from multiple sugars

Abstract

2,3-Butanediol (2,3-BDO) is a compound used in a variety of industries including fuel, rubber, cosmetics, pharmaceuticals and food additives. 2,3-BDO can be produced in an economical and environmentally friendly method through a biological production in addition to chemical synthesis. The cost of fermentation process for microbial production can be reduced through use of cheap raw materials (carbon sources) and development of strain with high productivity. Accordingly, efforts are being made to more economically produce high value-added products using multiple sugars derived from lignocellulosic biomass, which is an eco-friendly and renewable energy resource. However, most microorganisms show inefficient consumption of other sugars in the presence of glucose. In this study, Klebsiella oxytoca (K. oxytoca) with improved growth and consumption activity of four sugars was developed using foreign gene introduction and adaptive laboratory evolution strategy. In addition, whole genome resequencing and transcriptome analysis of evolved strain was performed to clarify the major factors and mechanisms contributing to improved phenotypes. And, metabolic engineering was carried out to enhance the 2,3-BDO synthesis pathway in evolved strain. Finally, the engineered K. oxytoca produced 2,3-BDO at high level in optimized fed-batch fermentation process. The developed strain in this study is considered as a promosing microorganism to be applicable to a wide range of lignocellulosic biomass for economic and sustainable production of 2,3-BDO in industry fields.