AN OVERVIEW OF PURIFICATION STRATEGIES FOR MICROBIAL MANNANASES

Abstract

β-Mannanases hydrolyze mannan-based hemicelluloses and liberate short β-1,4 manno oligomers, which can be further hydrolysed to mannose by β-mannosidases. Such enzymes are not only of academic interest but also they have potential biotechnological applications in a wide range of industrial enzyme market, including food and feed technology, coffee extraction, bioethanol production, slime control agents, pharmaceutical field, pulp and paper industry, etc. Purified mannanases are required for some of the industrial applications like food and pharmaceutical industry. Moreover, purification of mannanase has enabled their successful sequence determination and their three-dimensional structure leading to better understanding of kinetic mechanism. Mannanases from a large number of bacteria, fungi, and actinomycetes have been purified to homogeneity. This article presents a critical review of different strategies which have been employed for the purification of bacteria, fungi and actinomycetes mannanases. Since protein purification is normally done in series of sequential steps involving a combination of different techniques, the effect of a sequence of steps and the number of times each step is used has been analyzed. This will prove to be of immense help while planning mannanase purification. Moreover special features of this class of enzymes, such as carbohydrate binding domains (CBDs) and their importance in the development of affinity methodologies to increase and facilitate mannanase purification has also been discussed. New directions to improve mannanase separation and purification from fermentation media are described.