Enzymatic processes

Enzymes (/ˈɛnzaɪmz/) are proteins that act as biological catalysts (biocatalysts).

In terms of lignocellulosic biomass valorisation, enzymes find two main applications: i) biomass pretreatment, and ii) polysaccharides hydrolysis.

Enzymatic processes

Enzymatic hydrolysis processes allow to produce monomeric sugars from (ligno)cellulosic biomass by using specific enzymes (i.e. cellulases and hemicellulases) able to break down the chemical bonds in cellulose and hemicellulose polymers. Several factors can affect the efficiency of this process: accessible surface area and crystallinity of the biomass, as well as pH, time and temperatures of the process. Enzymatic hydrolysis is gaining increased attention with respect to acid hydrolysis due to equipment corrosion, energy consumption, non-recyclability of reagents, fermentation inhibitors production during acid hydrolysis. To increase the hydrolysis efficiency, a pretreatment step prior to enzymatic reaction is usually required due to the complex lignocellulosic biomass composition (Primary processing).