Engineering of <i>Klebsiella oxytoca</i> for the Production of 2,3-Butanediol from High Concentration of Xylose
Ji Won Cha, Seung Hoon Jang, Jaewoo Son, Jungyeon Kim, In‐Ho Jung, Kyoung Heon Kim, Yong Keun Chang, Ki Jun Jeong
Abstract
Klebsiella oxytoca is widely used for the biological production of 2,3-butanediol (2,3-BDO), a promising platform chemical with a broad range of applications. Here, to improve cell growth and production of 2,3-BDO under high concentration of xylose (100 g/L), we engineered K. oxytoca using an adaptive laboratory evolution and a biosensor-derived high throughput screening strategy. First, we developed a XylR-dependent xylose biosensor for the detection of intracellular xylose, and K. oxytoca containing the xylose biosensor was used for adaptive laboratory evolution in 100 g/L xylose. Cells were isolated by FACS screening, and the isolated strain (KO8S16) showed much improved cell growth with high xylose consumption rate (1.35 g/L/h) and 2,3-BDO productivity (0.53 g/L/h) compared with the wild-type strain. Through whole genome resequencing, it was revealed that a mutation in OmpR (a response regulator of osmotic stress) allowed to withstand high concentrations of xylose. Finally, fed-batch cultivation was performed by feeding high concentration of xylose, and K. oxytoca successfully produced 2,3-BDO at a concentration as high as 57.5 g/L by consuming 238.13 g/L xylose in 47 h.