Improved in situ saccharification of cellulose pretreated by dimethyl sulfoxide/ionic liquid using cellulase from a newly isolated Paenibacillus sp. LLZ1

• An environmental-friendly cellulase was newly isolated from soil samples.
• Developed a DMSO/ILs-cellulase system for the in situ saccharification of cellulose.
• Cellulose hydrolysis process was more energy efficient and environmentally friendly.

A cellulase producing strain was newly isolated from soil samples and identified as Paenibacillus sp. LLZ1. A novel aqueous-dimethyl sulfoxide (DMSO)/1-ethyl-3-methylimidazolium diethyl phosphate ([Emin]DEP)-cellulase system was designed and optimized. In the pretreatment, DMSO was found to be a low-cost substitute of up to 70% ionic liquid to enhance the cellulose dissolution. In the enzymatic saccharification, the optimum pH and temperature of the Paenibacillus sp. LLZ1 cellulase were identified as 6.0 and 40 °C, respectively. Under the optimized reaction condition, the conversion of microcrystalline cellulose and bagasse cellulose increased by 39.3% and 37.6%, compared with unpretreated cellulose. Compared to current methods of saccharification, this new approach has several advantages including lower operating temperature, milder pH, and less usage of ionic liquid, indicating a marked progress in environmental friendly hydrolysis of biomass-based materials.