High solid and low enzyme loading based saccharification of agricultural biomass

Abstract

Two agricultural biomass materials, namely wheat straw and sugarcane bagasse, were pretreated with NaOH and then used as substrates for enzymatic saccharification. After the pretreatment, the increase in glucan content and the decrease in lignin content were more than 65%, while less than 20% increase occurred in xylan content. The enzymatic saccharification was initiated with solid loading 9% (w/v), and then 8%, 7% and 6% (w/v) solid was fed at 8, 24, and 48 h, respectively. The final enzyme solid loading was 9.60 FPU/g solid and 30% (w/v), respectively. At 144 h, the produced glucose, xylose, and reducing sugar concentrations for wheat straw were 81.88, 20.30, and 115.25 g/L, respectively, and for sugarcane bagasse they were 125.97, 8.66, and 169.50 g/L, respectively. The final conversions of wheat straw and sugarcane bagasse were 34.57% and 50.85%, respectively. SEM images showed that the surface structure of the two materials changed a lot via alkali-pretreatment and enzymatic hydrolysis. In summary, a high concentration sugar is produced from the two agricultural biomass materials by high solid and low enzyme loading. Compared to wheat straw, sugarcane bagasse is more suitable for use in sugar production.