Progress and perspective on lignocellulosic hydrolysate inhibitor tolerance improvement in Zymomonas mobilis

• Main Authors: Yongfu Yang, Mimi Hu, Ying Tang, Binan Geng, Mengyue Qiu, Qiaoning He, Shouwen Chen, Xia Wang, Shihui Yang
• Format: Article
• Language: English
• Published: SpringerOpen 2018-02-01
• Series: Bioresources and Bioprocessing
• Subjects: Lignocellulose; Inhibitor; Zymomonas mobilis; Robustness; Adaptive laboratory evolution (ALE); Mutagenesis
• Online Access: http://link.springer.com/article/10.1186/s40643-018-0193-9

Abstract Pretreatment is the key step to overcome the recalcitrance of lignocellulosic biomass making sugars available for subsequent enzymatic hydrolysis and microbial fermentation. During the process of pretreatment and enzymatic hydrolysis as well as fermentation, various toxic compounds may be generated with strong inhibition on cell growth and the metabolic capacity of fermenting strains. Zymomonas mobilis is a natural ethanologenic bacterium with many desirable industrial characteristics, but it can also be severely affected by lignocellulosic hydrolysate inhibitors. In this review, analytical methods to identify and quantify potential inhibitory compounds generated during lignocellulose pretreatment and enzymatic hydrolysis were discussed. The effect of hydrolysate inhibitors on Z. mobilis was also summarized as well as corresponding approaches especially the high-throughput ones for the evaluation. Then the strategies to enhance inhibitor tolerance of Z. mobilis were presented, which include both forward and reverse genetics approaches such as classical and novel mutagenesis approaches, adaptive laboratory evolution, as well as genetic and metabolic engineering. Moreover, this review provided perspectives and guidelines for future developments of robust strains for efficient bioethanol or biochemical production from lignocellulosic materials.