Strategies To Achieve High-solids Enzymatic Hydrolysis Of Lignocellulosic Biomass

To make biomass-to-biosugar conversion economically feasible, enzymatic hydrolysis at high-solids loading is essential. Three strategies were presented to achieve high solids loading while maximizing carbohydrate conversion on dilute acid pretreated corn stover(PCS) and autohydrolysis pretreated hardwood(PHw), which are Fedbatch, Thickening, and Recycle processes. Enzymatic hydrolysis was performed at insoluble solids(IS) of 15% using washed substrate.For the substrate of PCS, the total sugar concentration increased from 31.8 g/L to 99.3 g/L when the insoluble solids content increased from 5% IS to 15% IS, while the final sugar conversion was decreased from 78.4% to 73.2%. All these three processes could improve the high-solids enzymatic hydrolysis of PCS. For the fed-batch process, a total sugar conversion efficiency of 76.8% was achieved when solid was split into 60:20:20 ratio, with all enzymes added first. For the thickening process, a sugar conversion of 76.5% was realized when the filtrate was recycled to simulate a steadystate process. Lastly, the recycle process was evaluated and the highest carbohydrate conversion of 81.4% was achieved.Differing with PCS, which has showed that the sugar conversion gradually decreased as the solids concentration increased, the decrease of sugar conversion for the PHw was more rapidly. An increase in the solids concentration from 5% IS to 10% IS with PHw resulted in a 15.9% decrease in total sugar conversion, and a further increase to 10% IS and 15% IS resulted a 9.3% decrease in total sugar conversion. Not all these three process performed well on high-solids enzymatic hydrolysis of PHw. The fed-batch process didn’t show any improvement on the final sugar conversion. With the thickening process, the sugar conversion increased to 64.3% which was higher than 58.3% achieved with base-case 15% IS, but not comparable to that at 5% IS(76.3%). The recycle process achieved the highest carbohydrate conversion of 71.8%, which was comparable to that at 5% IS.