Abstract:

Objective: To produce a large scale of succinic acid through the bioconversion of crop straw. Methods: Crop straw was pretreated by steam-explosion method. Then Trichoderma viride was used to degradating crop straw in the first-step fermentation and Actinobaccillus succinogenes was used for producing succinic acid in the second-step fermentation. Results: The yield of pentose and hexose is about 49.4 g/L when the conditions of first-step fermentation were as follows: fermentation at 30 ℃ for 36 h, then enlargement of the broth by 8 times of volume and hydrolysis at 55 ℃ for 24 h. The yield of succinic acid is about 67 g/L when the second-step fermentation condition was as follows: jar pressure of CO2 0.11 MPa, rotation rate 250 r/min, and fermentation at 37 ℃ for 40 h. Conclusions: The two-step fermentation technology is worth extending to industrial production of succinic acid from crop straw.

Key words: crop straw, succinic acid, Actinobacillus succinogenes, Trichoderma viride, two-step fermentation