What is the best way to assess the hydrolytic performance of new cellulase preparations on various pretreated lignocellulosics?

A combination of pretreatment and effective hydrolysis is required to reduce the amount of enzyme and time required for hydrolysis. The enzymatic hydrolysis of biomass is a heterogeneous reaction which is influenced by many interdependent qualitative and quantitative factors. These include the reactivity/specific surface area of the cellulose, the “cellulase” mixture’s composition and stability, the operating conditions that are used and several other enzyme and substrate conditions. These factors all contribute to the enzyme dosage and reaction time that are required to achieve effective hydrolysis.  A review of the literature indicates that there is still no general consensus on how to best compare the catalytic performance of different enzyme mixtures. In the work that will be presented the advantages and limitations of previous approaches employed to assess the “hydrolytic potential” of a “cellulase mixture” will be described. These established methods will be compared to an “Enzymatic Biomass Hydrolyzability Logarithm Model” that involves a minimum amount of parameters but with broad applicability to help validate and describe the kinetics during the key phase of hydrolysis (to achieve 20-90% hydrolysis yields). The enzymatic hydrolysis of pretreated biomass substrates will be described as a function of initial enzyme dosage and reaction time. Examples will be given to illustrate how this model can used to quantitatively determine and compare the hydrolytic performance of various “cellulase mixtures” and how the choice of biomass substrate, pretreatment severity and hydrolysis operating conditions can all influence the performance of novel cellulase preparations.