Succinic acid production from softwood with genome-edited Corynebacterium glutamicum using the CRISPR-Cpf1 system

Abstract

Background: Corynebacterium glutamicum is a useful microbe to produce succinic acid, a bio-based platform chemical, under anaerobic condition. The knock-out mutant of lactate dehydrogenase 1 gene, Δldh1-6, was generated by using CRISPR-Cpf1 genome editing system. HAPC (hydrogen peroxide and acetic acid) pretreatment is a softwood-favorable. Results: In the 1-5% hydrolysate, the best condition to produce succinic acid from the hydrolysate was confirmed to ferment 4% hydrolysate, resulted in 14.82 g L-1 succinic acid production for 6 h, which reached to 2.47 g L-1 h-1 productivity. No production of acetic acid and lactic acid was detected during the fermentation. However, 2.0 g L-1 lactic acid and 0.41 g L-1 acetic acid were formed in the fermentation of 5% hydrolysate while 9.64 g L-1 succinic acid was produced. Conclusion: These results show that the single gene knock-out, Δldh1-6 mutant, is sufficiently available for succinic acid production from hydrolysate of pine wood.