The cellulolytic system of Thermobifida fusca.

ABSTRACT

The process of bioethanol production from biomass comprises pretreatments and enzyme-mediated hydrolysis to convert lignocellulose into fermentable sugars. Because of the recalcitrant character of cellulose, the enzymatic hydrolysis is considered the major challenge in this process to be economically competitive. These technical difficulties highlight the need for the discovery of new enzymes to optimize and lower the cost of current technologies. Microorganisms have developed efficient systems for cellulose degradation. Among cellulolytic microbes, Thermobifida fusca possesses great physiological and cellulolytic characteristics (thermostability, high activity and tolerance to a broad pH range) making it an interesting organism to be studied from an applied perspective. In this review we describe the main enzymes/proteins produced by T.fusca (cellulases, xylanases, mannanase, manosidase, CBM33 and CelR), the effect of substrate on T. fusca proteome, enzyme improvement approaches, synergism between enzymes/proteins and artificial cellulosomes.