A review on the production of fermentable sugars from lignocellulosic biomass through conventional and enzymatic route—a comparison

The scarcity of fossil fuels has urged the economically developed countries to find the resources for an alternative energy sources. In apprehension to this, biofuels, like bioethanol and biobutanol, produced from lignocellulosic biomass were considered as potential alternative. There are several methods for the pretreatment of biomass before it is being used as a feedstock for the production of fermentable sugars. However, one of the crucial concerns here is to enumerate an economic pretreatment scheme that can be implemented in large scale for the production of mostly exposed cellulosic part from biomass. This will ensure an effective hydrolysis of cellulose for the production of fermentable sugars and the production of biobutanol from these derived sugars. Moreover, the keynote understanding of an effective fermentation is the production of less inhibitory compounds like furfural, hydroxymethyl furfural during the hydrolysis of cellulose. Enzymatic hydrolysis of cellulose was reported as the most efficient method is this aspect. Trichoderma sp. was found the mostly used resources for the enzyme called cellulase and Aspergillus sp. for hemicellulase enzymes. The most crucial part here is the isolation of proper enzyme that will increase the rate of hydrolysis. Moreover, selection of proper pretreatment process will be a key benefit to the production of fermentable sugars through enzymatic hydrolysis. Based on the biomass nature, the evaluated hot water pretreatment followed by enzymatic hydrolysis with a provision of enzyme reusability (like encapsulated or enzyme separation with membrane) seems to be promising for enhanced biofuel-production.