Cellulase Production from Bacillus subtilis SV1 and Its Application Potential for Saccharification of Ionic Liquid Pretreated Pine Needle Biomass under One Pot Consolidated Bioprocess

Abstract

Pretreatment is the requisite step for the bioconversion of lignocellulosics. Since most of the pretreatment strategies are cost/energy intensive and environmentally hazardous, there is a need for the development of an environment-friendly pretreatment process. An ionic liquid (IL) based pretreatment approach has recently emerged as the most appropriate one as it can be accomplished under ambient process conditions. However, IL-pretreated biomass needs extensive washing prior to enzymatic saccharification as the enzymes may be inhibited by the residual IL. This necessitated the exploration of IL-stable saccharification enzymes (cellulases). Current study aims at optimizing the bioprocess variables viz. carbon/nitrogen sources, medium pH and fermentation time, by using a Design of Experiments approach for achieving enhanced production of ionic liquid tolerant cellulase from a bacterial isolate Bacillus subtilis SV1. The cellulase production was increased by 1.41-fold as compared to that under unoptimized conditions. IL-stable cellulase was employed for saccharification of IL (1-ethyl-3-methylimidazolium methanesulfonate) pretreated pine needle biomass in a newly designed bioprocess named as "one pot consolidated bioprocess" (OPCB), and a saccharification efficiency of 65.9% was obtained. Consolidated bioprocesses, i.e., OPCB, offer numerous techno-economic advantages over conventional multistep processes, and may potentially pave the way for successful biorefining of biomass to biofuel, and other commercial products.

Exceptional Solvent Tolerance inYarrowia lipolyticaIs Enhanced by Sterols

“…4). In addition, harmful interactions between the IL and membrane result in a cascade of detrimental effects on cellular processes including DNA damage, enzyme inactivation, and protein degeneration (59, 63–65), as observed by reduced sterol and chitin contents (Fig. 5D and SI Appendix, Fig.…”

Ionic Liquids in Biomass Processing

“…Biomass Reference 1-Ethyl-3-methylimidazolium acetate Bamboo, Hinoki Cypress wood, Sugarcane bagasse, Pine wood [81,82,83,84,85,86] Triethylammonium hydrogensulfate with 20 wt % water Miscanthus giganteus [68] Cholinium lysinate, Cholinium acetate Sorghum, Switchgrass, Eucalyptus, Pine [87,88,89] 1-Ethyl-3-methylimidazolium methanesulfonate Pine needles [90] 1-Butyl-3-methylimidazolium acetate Rice straw [91] 1-Ethyl-3-methylimidazolium acetate (42 wt. %) in DMSO Switchgrass [92] 1-Ethyl-3-methylimidazolium acetate, 1-Allyl-3-methylimidazolium formate and acetate…”

Potential application spectrum of microbial proteases for clean and green industrial production

“…Furthermore, considering the ever-growing world energy demand, industrialization, rapidly depleting fossil-fuel reserves, environmental health issues, there is emphasis on development of sustainable industrial technologies that are environmentally safe and involve minimum emissions (Jegannathan and Nielsen 2013;Vaid and Bajaj 2017). As a result there is a paradigm shift from traditional concepts of chemical-based production and manufacturing to eco-benign processes that are equally efficient and economic (Sarrouh et al 2012;Nargotra et al 2016). Application of enzymes for industrial processes may contribute significantly towards development of environmentally benign processes (Bajaj and Jamwal 2013;Mhamdi et al 2017).…”