Co-fermentation of glucose and xylose from sugarcane bagasse into succinic acid by Yarrowia lipolytica

Abstract

This study focused on the feasibility of Y. lipolytica PSA02004 co-utilising glucose and xylose from sugarcane bagasse hydrolysate in succinic acid (SA) fermentation. Optimum pH, temperature and cellulase dosage of enzymatic hydrolysis through optimisation were pH 5, 50 °C and 40 FPU/g, respectively. The hydrolysis yields for glucose and xylose were 0.35 ± 0.00 g/g and 0.15 ± 0.00 g/g, respectively. A feasibility study using a 2.5-L bioreactor demonstrated that mixed glucose and xylose could be utilised for SA production, with the resultant SA titre, yield and productivity of 28.2 ± 0.6 g/L, 0.55 ± 0.01 g/g and 0.36 ± 0.01 g/L/h, respectively. Then, the investigation of nutrient-limiting factor showed 40 g/L of initial glucose concentration and 8.4 g/L of initial xylose concentration containing hydrolysate and 2% CSL were the optimum medium composition in SA fermentation. SA production using sugarcane bagasse hydrolysate was conducted, in which SA titre, yield and productivity were 33.2 ± 0.3 g/L, 0.58 ± 0.01 g/g and 0.33 ± 0.01 g/L/h, respectively. The experimental results reported in this study show that glucose and xylose in sugarcane bagasse hydrolysate were successfully co-utilised by Y. lipolytica PSA02004 in SA production. This implies a sugarcane waste biorefinery could lead to a generic feedstock for the efficient production of succinic acid.