Cellulases: Classification, Methods of Determination and Industrial Applications

Abstract

Microbial cellulases have been receiving worldwide attention, as they have enormous potential to process the most abundant cellulosic biomass on this planet and transform it into sustainable biofuels and other value added products. The synergistic action of endoglucanases, exoglucanases, and β-glucosidases is required for the depolymerization of cellulose to fermentable sugars for transformation in to useful products using suitable microorganisms. The lack of a better understanding of the mechanisms of individual cellulases and their synergistic actions is the major hurdles yet to be overcome for large-scale commercial applications of cellulases. We have reviewed various microbial cellulases with a focus on their classification with mechanistic aspects of cellulase hydrolytic action, insights into novel approaches for determining cellulase activity, and potential industrial applications of cellulases.

Aromatic amino acids in the cellulose binding domain of Penicillium crustosum endoglucanase EGL1 differentially contribute to the cellulose affinity of the enzyme

“…Due to their critical function in the bioconversion of cellulosic materials, cellulases have deeply allured the interest of researchers. Currently, many cellulases have already been cloned and characterized genetically and biochemically, and this pace of progress is continuously accelerating [3]. …”

Efecto del pretratamiento con ácido sulfúrico diluido sobre la hidrólisis enzimática del Panicum maximum

“…Las enzimas presentaron una actividad de 1000 unidades de hidrolisis de biomasa (BHU)/g de mezcla y 250 unidades de celobioasa (CBU)/g de mezcla, respectivamente. Estas actividades enzimáticas se verificaron empleando el protocolo descrito por Sharma et al (2016), presentando una variación menor al 5% respecto a lo reportado en las fichas técnicas. Para la prueba de digestibilidad, se dosificó una actividad de 25 BHU/g de biomasa pretratada de celulasas y 0,27 CBU/g de biomasa pretratada de β-glucosidasas, limites superiores de dosificación de cada enzima según el fabricante.…”

Production, purification, characterization and usage of a detergent additive of endoglucanase from isolated halotolerant Amycolatopsis cihanbeyliensis mutated strain Mut43

“…3.2.1.21). Endoglucanases cleave cellulose chains randomly to produce cello-oligosaccharides (Sharma et al 2016). Endoglucanases for some industrial applications such as the hydrolysis of cellulolytic biomass for bioethanol production, food and feed improvement, fruit juice clarification, bio-polishing of cellulosic fabrics, and effective-washing of laundry, are produced by some fungi and bacteria.…”

“…Many commercial cellulases produced by fungi, such as Aspergillus niger, Trichoderma reesei, Penicillium sp. and Rhizopus sp., have limited use in industrial applications because their activity is significantly reduced in extreme conditions (Sharma et al 2016). Therefore, research regarding extraction and characterization of cellulases that tolerate extreme conditions from novel microorganisms is gaining more attention.…”