Preparation of Succinic Acid from Crop Straw via Two-step Fermentation

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.