Bioprospecting thermostable cellulosomes for efficient biofuel production from lignocellulosic biomass

Abstract

The adverse climatic conditions due to continuous use of fossil-derived fuels are the driving factors for the development of renewable sources of energy. Current biofuel research focuses mainly on lignocellulosic biomass (LCB) such as agricultural, industrial and municipal solid wastes due to their abundance and renewability. Although many mesophilic cellulolytic microorganisms have been reported, efficient and economical bioconversion to simple sugars is still a challenge. Thermostable cellulolytic enzymes play an indispensible role in degradation of the complex polymeric structure of LCB into fermentable sugar stream due to their higher flexibility with respect to process configurations and better specific activity than the mesophilic enzymes. In some anaerobic thermophilic/thermotolerant microorganisms, few cellulases are organized as unique multifunctional enzyme complex, called the cellulosome. The use of cellulosomal multienzyme complexes for saccharification seems to be a promising and cost-effective alternative for complete breakdown of cellulosic biomass. This paper aims to explore and review the important findings in cellulosomics and forward the path for new cutting-edge opportunities in the success of biorefineries. Herein, we summarize the protein structure, regulatory mechanisms and their expression in the host cells. Furthermore, we discuss the recent advances in specific strategies used to design new multifunctional cellulosomal enzymes, which can function as lignocellulosic biocatalysts and evaluate the roadblocks in the yield and stability of such designer thermozymes with overall progress in lignocellulose-based biorefinery.

Antigen-43-mediated surface display revealed in Escherichia coli by different fusion sites and proteins

“…Moreover, the cellulase was also displayed in another strain, Zymobacter palmae (Kojima et al 2012). Cellulase-mediated biodegradation of cellulose is one promising approach in global carbon recycling (Ng et al 2010, 2011), and this biodegradation is also a potential consolidated bioprocessing (CBP) platform for effective production of biocommodities (Arora et al 2015;Liao et al 2011;Obeng et al 2017). Therefore, BsCel5 surface display by Ag43 may be a new approach for whole-cell catalysis and CBP in the future.…”

Potential of Thermotolerant Ethanologenic Yeasts Isolated from ASEAN Countries and Their Application in High- Temperature Fermentation

“…These thermotolerant strains are expected to provide a benefit for the industries because they are more robust and resistant to many stressors [14]. In addition, some of these thermotolerant microorganisms can produce distinctive enzymes that function under relatively high temperature conditions [16][17][18]. Thermotolerant yeasts have been found and isolated from a number of countries [19][20][21][22][23][24][25][26][27][28].…”

SELECTION AND IDENTIFICATION OF A NOVEL THERMOTOLERANT Kluyveromyces marxianus STRAIN FOR VALORIZATION OF LACTOSE WASTE INTO ETHANOL

“…However, the problem could be alleviated by using thermotolerant strains of yeast, which could capable to grow and produced ethanol at elevated temperatures. Other than thermotolerance, broad substrate utilization ability, higher saccharification rate, ethanol yieldand low energy requirement are the desirable traits for the successful exploitation of yeast for ethanol production (Dung et al, 2012;Kumar et al, 2013;Arora et al, 2015;Scully & Orlygsson, 2015). Therefore, the selection of the yeast strain is very crucial for bioconversion of different feedstock into ethanol.…”