| Abstrakt: |
Aloe vera (AV) leaf rind, a potent second-generation lignocellulosic biomass, was employed for fermentative co-production of lactic acid (LA) and acetone-butanol-ethanol (ABE) using Bacillus coagulans MTCC 492 and Clostridium acetobutylicum MTCC 11274, respectively. A systematic sequential biomass treatment using deep eutectic solvents (DESs) (Glyc, choline chloride:glycerol, and Reln, choline chloride:urea), mild sulfuric acid (1%, v/v) (MSA), and cellulase was adopted for lignin fractionation, pentose (C5), and hexose (C6) hydrolysates preparation. It has been observed that adoption of DES pretreatment tends to reduce the fermentative inhibitors (predominantly lignin derived) by 2.36-fold after MSA saccharification as compared to the conventional acid (2%, v/v) (CA) pretreatment. Additionally, DES exerted a significant structural disintegration of biomass as evident from SEM, FTIR, NMR, and XRD that favored subsequent saccharification. Maximum delignification of 76.87% (w/w) was obtained when biomass was treated with Glyc-MSA that in turn yielded 70.71 g/L of total sugar. Bacillus coagulans MTCC 492, an efficient LA producer through pentose sugar utilization, resulted in 35.87 g of LA/L of the hydrolysate. Subsequently, the cellulose-rich residual biomass (after Glyc-MSA) when hydrolyzed enzymatically using cellulase yielded a hydrolysate containing 34.44 g/L of total sugar. Clostridium acetobutylicum MTCC 11274 was employed for fermentation of this C6 sugar-rich hydrolysate that resulted in 4.83 g/L of total ABE. Through this study, a multi-product development strategy was formulated for systematic utilization of AV leaf rind cell wall components (lignin, cellulose, and hemicellulose) towards its segregated bio-based utilization. [ABSTRACT FROM AUTHOR] |
Full text from SpringerLink