Batch-based enzymatic saccharification of sweet sorghum bagasse

ABSTRACT

To improve enzymatic digestibility and sugar concentration, sweet sorghum bagasse was pretreated with alkali and liquid hot water, and then subjected to fed-batch enzymatic hydrolysis. Scanning electron microscopy assay suggested that different pretreatment methods resulted in different composition and structure of residues; these changes had a significant influence on cellulose hydrolysis. Fresh substrate was pretreated and then added at different amounts during the first 48 h to yield a final dry matter content of 30% (w/v). For liquid hot water pretreatment, a maximal glucose concentration of 95.71 g/L, corresponding to 52.85% xylan removal, was obtained with the sweet sorghum bagasse pretreated at 184°C for 18 min. NaOH soaking at ambient conditions removed lignin up to 60%, and the subsequent hydrolysis with cellulase loading of less than 10 FPU/g DM, and substrate supplementation every few hours yield the high glucose and xylose concentrations of 114.89L and 29.93 g/L, respectively after 144 h.

KEYWORDS:

• Alkali pretreatment
• enzymatic saccharification/hydrolysis
• fed-batch
• liquid hot water pretreatment
• sweet sorghum bagasse

Additional information

Funding

This work was funded by the National High-tech R&D Program (2013AA065803), Program of National Natural Science Foundation of China (21306196, 21176237, 21211140237), Science & Technology Project of Guangzhou (2013J4300026), and Guangdong science and technology research program (2013B010403021).