CURRENT CHALLENGES ON THE PRODUCTION AND USE OF CELLULOLYTIC ENZYMES IN THE HYDROLYSIS OF LIGNOCELLULOSIC BIOMASS

The second generation (2G) ethanol obtained from lignocellulosic biomass has been considered as a potential alternative source of energy for the transportation sector. However, the technologies to convert lignocellulose into fermentable sugars still face several challenges. One of the major challenges of this process is related to the cost of the cellulolytic enzymes. Thus, the development of bioprocesses for enzyme production and strategies to increase the final yield of the enzymatic hydrolysis reactions are required to ensure the economic feasibility of the biomass conversion process. In this review, it is discussed the progress related to fungal enzyme technology over the past few years with major emphasis on the biocatalysts needed for cellulose degradation as well as on cultivation strategies for the production of enzymes on-site. The potential of applying secretome analysis as a tool for the characterization of the enzymatic complexes and some limitations on the use of enzymatic cocktails in the saccharification step, such as the unproductive adsorption of enzymes onto lignin are also discussed in light of the recent literature.