Microbial Xylanases: Sources, Types, and Their Applications

Abstract

Biomass conversion to an utilizable energy sources such as monomer sugars using enzymatic hydrolysis has been emerged as the current technology which promises the future energy. In nature, bioconversion process of biomass is mediated by a group of biofunctional hydrolytic enzymes. These enzymes generally work in cooperative synergetic action to facilitate enhanced effective degradation of biomass. Xylanase is one of the crucial hydrolytic enzymes involved in hydrolysis of xylan, the hemicellulose which constitutes 15–30 % of the plant biomass. This chapter discusses in detail about the enzymatic hydrolysis of xylan by the xylolytic enzyme endo-1,4-b-xylanase, its occurrence in nature and mode of action, structure and classifications, current methods for its production, purification, and character-ization. In addition, the major and recent industrial applications of this enzyme were highlighted as well. 7.1 Introduction Nowadays, the governments promote extensive researches for the development of an alternative transportation fuel from a renewable energy sources, realizing the upcoming major energy crisis due to the depletion of petroleum-derived fuels. As an initiative, the department of energy in US has started producing biofuels with a set target of 60 billion gallon per year by 2030. Europe also has the similar targets by that time to replace 25 % of petroleum-based liquid transportation fuel by biofuels (Himmel et al. 2007). However, it is a challenging target since the biofuel production using substrates such as sugar cane and corn has limited capacity to supply such a huge volumes. Apart from this, in many countries people protest against the use of food crops for biofuel production and many debates that it leads to a major food crisis. As a remedy, researchers found out that the lignocellulose