Microbial β-glucosidase: Source, production and applications
Oladoja EO, Oyewole OA, Adamu BB, Balogun AN, Musa OI
β-glucosidase is an enzyme that is ubiquitous in nature and is produced by bacteria, fungi, plants and animals, including humans. Although, microorganisms especially fungi are considered the best choice for enzyme production as in industrial utilization especially from Trichoderma reesei, the filamentous fungus Acremonium persicinum, Aspergillus oryzae and Thermoascus aurantiacus. Classification of β-glucosidase is based on substrate specificity, nucleotide sequences identity and hydrophobic cluster analysis. β-glucosidase is known to hydrolyse the glycosidic bond of a carbohydrate moiety to release non-reducing terminal glycosyl residues, glycoside and oligosaccharides. Microbial β-glucosidases are produced in low quantities, and are inhibited by glucose, which is their end product. This results in accumulation of cellobiose during cellulolysis, which in turn inhibits endo-glucanase and exo-glucanase thereby making β-glucosidase the key enzyme in determining the cellulase efficiency. β-glucosidases have diverse biotechnological applications in food, biofuel, and agricultural industries. The search for novel and improved β-glucosidase is still continued to fulfil demand of an industrially suitable enzyme with high productivity of β-glucosidase and high glucose tolerance, thermostability and catalytic efficiency. This review article, describes the classes of β-glucosidases, mode of actions, microbial sources of β-glucosidases, production methods, factors affecting their production and biotechnological application.