Enhanced High-Solids Fed-Batch Enzymatic Hydrolysis of Sugar Cane Bagasse with Accessory Enzymes and Additives at Low Cellulase Loading
Enhanced High-Solids Fed-Batch Enzymatic Hydrolysis of Sugar Cane Bagasse with Accessory Enzymes and Additives at Low Cellulase Loading
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DOI：
10.1021/acssuschemeng.8b01972
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发表时间：
2018-10-01
影响因子：
8.4
通讯作者：
Zhang, Junhua
中科院分区：
文献类型：
--
作者：
Mukasekuru, Marie Rose;Hu, Jinguan;Zhang, Junhua
High cellulase loading is still a major impediment in the production of fermentative sugars from high-solids enzymatic hydrolysis of lignocellulosic substrates in the enzyme-based "biorefinery" industry. This study attempted a high-solids (20%) enzymatic hydrolysis of lignocellulosic substrate at a very low cellulase loading with mixed use of additives and accessory enzymes by fed-batch mode. To avoid the high initial biomass viscosity, the high-solids enzymatic hydrolysis of lignocellulosic substrates was initiated with a solids content of 8%. Thereafter, 4% of the additional substrates were consecutively fed into the hydrolysis system after 6, 12, and 18 h to reach a final solids content of 20%. Some additive mixtures (40 mg/g substrateTween 80 + 10 mg/g substrate tea saponin +20 mg/g substrate BSA) were observed to enable this fed-batch hydrolysis to increase 30% of the glucose yield after the 48 h. The combination of these additives and accessory enzymes (2.4 mg/g substrate xylanase and g substrate AA9) in the high-solids hydrolysis system further boosted the sugar release. This allowed us to achieve an industrially relevant sugar yield (83% cellulose and 90% xylan hydrolysis) and fermentable sugar titer (similar to 160 g/L) after 72 h, with a low cellulase enzyme loading (3 FPU/g substrate). Our results indicate that the fed-batch substrate addition process is a favorable model for high-solids enzymatic hydrolysis of lignocellulosic substrates. Moreover, the synergism between the additives and accessory enzymes can greatly boost the high-solids enzymatic hydrolysis of lignocellulosic substrates.
