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

Abstract

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 °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 fed-batch 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.

Keywords: Enzymatic hydrolysis; Fermentation; Liquid hot water; Succinic acid; Sugarcane bagasse.