Liquid hot water pretreatment combined with high-solids enzymatic hydrolysis and fed-batch fermentation for succinic acid sustainable processed from sugarcane bagasse

In order to sustainable process of bio-succinic acid (SA), response surface methodology (RSM) was applied to optimize liquid hot water pretreatment pretreatment of sugarcane bagasse (SCB), followed by high-solids enzymatic hydrolysis of pretreated residual that without washing, then the hydrolysates and partial pretreatment liquid were used as carbon sources for SA fermentation. Results showed that the highest sugars yield could be achieved at pretreatment conditions of temperature 186 degrees C, time 25 min and solid-to-liquid ratio 0.08; enzymatic digestion the pretreated residuals at 20 % (w/v) solid content via enzymes reconstruction and fedbatch strategy, the obtained sugars reached to 121 g/L; by controlling the nutrition and conditions of the fermentation process, most of the C5 and C6 sugars in the hydrolysate and pretreatment liquid were converted into SA with a conversion rate high to 280 mg/g SCB. This study can provide a novel clue for clean and efficient biorefining of chemicals.

Automated summary

This study applied response surface methodology to optimize the liquid hot water pretreatment of sugarcane bagasse, and achieved the highest sugar yield under the pretreatment conditions of 186°C, 25 min, and solid-to-liquid ratio of 0.08. By enzymatic hydrolysis of the pretreated residuals at 20% (w/v) solid content, the obtained sugars reached 121 g/L. Through controlling the fermentation process, most of the C5 and C6 sugars were converted into succinic acid with a high conversion rate of 280 mg/g SCB. This study provides a new clue for clean and efficient biorefining of chemicals.