Diversity of Paenibacillus sp. LLZ1 Cellulase and its Improved Enzyme Activity and Stability in the Ionic Liquid 1-Ethyl-3-methylimidazolium Diethyl Phosphate

Wei Yang, Min Zhou, Lishi Yan, Xin Ju, Liangzhi Li

Abstract


The stability of cellulase in the presence of ionic liquids (ILs) is pivotal for the in situ saccharification of cellulose. This study investigated the effects of various carbon sources on the cellulase production of Paenibacillus sp. LLZ1. The results showed that the activities of both the total cellulase and endoglucanase induced by microcrystalline cellulose were higher than those induced by other examined carbon sources. Simultaneously, a zymography analysis revealed the presence of seven protein bands (carboxymethylcelluloses 3, 4 and 6 through 10) with endoglucanase activity when MCC was used as the carbon source for culturing Paenibacillus sp. LLZ1. The endoglucanase induced by MCC showed stability in a 25% solids 1-ethyl-3-methylimidazolium diethylphosphate ([Emim]DEP) solution. Furthermore, the addition of metal ions and surfactants increased the endoglucanase activity in the [Emim]DEP solution, where 0.5 mM of Fe2+ and 0.1% of polysorbate (PSM 60) led to 11% and 29% increases in filter paper activity, respectively. Finally, three types of biomass (MCC, bagasse cellulose, and bagasse) were used as raw materials for in situ enzymatic hydrolysis when involved 5% [Emim]DEP and 0.1% polyoxyethylene (60) sorbitan monostearate (PSM 60). Fourier-transform infrared spectroscopy and specific surface area measurements were used to explain the effects of PSM 60 on the hydrolysis efficiency of these three biomasses.

Keywords


Biomass; Cellulase; Endoglucanase activity; Ionic liquid; Paenibacillus sp. LLZ1; Surfactant

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