Effect of non-enzymatic proteins on enzymatic hydrolysis and simultaneous saccharification and fermentation of different lignocellulosic materials

Abstract

Non-enzymatic proteins were added during hydrolysis of cellulose and simultaneous saccharification and fermentation (SSF) of different biomass materials. Bovine serum albumin (BSA), a model non-enzymatic protein, increased cellulose and xylose conversion efficiency and also enhanced the ethanol yield during SSF of rice straw subjected to varied pretreatments. Corn steep liquor, yeast extract, and peptone also exerted a similar effect as BSA and enhanced the enzymatic hydrolysis of rice straw. Compared to the glucose yields obtained after enzymatic hydrolysis of rice straw in the absence of additives, the glucose yields after 72h of hydrolysis increased by 12.7%, 13.5%, and 13.7% after addition of the corn steep liquor, yeast extract, and peptone, respectively. This study indicated the use of BSA as an alternative to intensive pretreatment of lignocellulosic materials for enhancing enzymatic digestibility. The utilization of non-enzymatic protein additives is promising for application in glucose and ethanol production from lignocellulosic materials.

Recombinant family 3 carbohydrate-binding module as a new additive for enhanced enzymatic saccharification of whole slurry from autohydrolyzed Eucalyptus globulus wood

“…Results also show that the effect is dose-dependent, with the effective dosage being within the reported range for other proteins (e.g. BSA, 10-50 mg/g) (Yang and Wyman 2006;Wang et al 2015).…”

“…The use of synergistic proteins (accessory or helper proteins) that can synergistically cooperate with, or protect, cellulases is an emerging strategy for enhanced saccharification of lignocellulosic biomass, resulting in cost reduction with respect to cellulase usage and the enzymatic saccharification of lignocellulose (Kim et al 2014). Notably, protein supplementation might save cellulase loadings by at least 50% without decreasing hydrolysis yield (Wang et al 2015). Nonhydrolytic proteins, such as bovine serum albumin (BSA), expansins and expansin-like proteins, engineered peptides, peptone, yeast extract, and carbohydrate-binding modules (CBMs), have been tested in cellulosic or lignocellulosic saccharification with significant positive effects (Kim et al 2014;Liu et al 2016).…”

“…non-hydrolytic ''opening up'' or disruption of cellulose), among other functions (e.g. enzyme protection from thermal deactivation) (Wang et al 2015), depending on the protein itself and substrate nature.…”

Toward a fundamental understanding of cellulase‐lignin interactions in the whole slurry enzymatic saccharification process

“…The use of bovine serum albumin (BSA) as lignin‐block additives was first reported by Yang and Wyman in 2006 . Several other exogenous non‐enzymatic proteins, such as peptone, protein digest, and yeast extract, have also been studied as a substitution of pure BSA owing to their advantages in cost and availability . The efficiency of proteinous additives is summarized in Table .…”

Co-fermentation using Recombinant Saccharomyces cerevisiae Yeast Strains Hyper-secreting Different Cellulases for the Production of Cellulosic Bioethanol

“…This was followed by washing with deionized water until the pH was neutralised, and then the material was dried at 60 °C until a constant dry weight was obtained. The pre-treated rice straws were milled to pass through a 2-mm screen 49 . EFBs, as another cellulosic substrate, were prepared as follows.…”