Systems Metabolic Engineering of Corynebacterium Glutamicum to Overcome the Cellular Toxicity Derived from Cellulosic Hydrolysate

Pretreatment of cellulosic biomasses by acid hydrolysis generates cellular inhibitors such as Furfural, HMF, and acetic acid etc. Therefore, it is necessary to overcome the toxicity in the hydrolysate during fermentation. Our goal is to develop the strain capable of being tolerant to the inhibitors. We investigated the effect of the inhibitors to Corynebacterium glutamicum, which is widely known as an amino acid producer and potential microbial cell factory. Cellular growth rates of C. glutamicum were decreased with various cellular inhibitors, including furfural that is a derivative of furan in the hydrolysate. C. glutamicum grown with furfural showed over 2-folds of reactive oxygen species stresses. In addition, the lower conversion rate of furfural and glucose uptake rate were measured. We have engineered C. glutamicum by overexpressing the target genes identified through both bioinformatics search and DNA microarray. When we cultivated the engineered strains with furfural, the growths were recovered as about 70% percent of growth rate of wild-type grown without furfural. Several metabolic engineering approaches could further improve the tolerance in C. glutamicum. This work was supported by the National Research Foundation of Korea Grant funded by the Korean Government (MEST) (2014, University-Institute cooperation program) and ‘Creative Allied Program (CAP)’ through the Korea Research Council of Fundamental Science and Technology (KRCF) and Korea Institute of Science and Technology (KIST).