Biorefining of Waste Paper Biomass: Increasing the Concentration of Glucose by Optimising Enzymatic Hydrolysis

Abstract

Waste copier paper is a potential substrate for the production of glucose relevant for manufacture of platform chemicals and intermediates, being composed of 51% glucan. The yield and concentration of glucose arising from the enzymatic saccharification of solid ink-free copier paper as cellulosic substrate was studied using a range of commercial cellulase preparations. The results show that in all cellulase preparations examined, maximum hydrolysis was only achieved with the addition of beta-glucosidase, despite its presence in the enzyme mixtures. With the use of Accellerase® (cellulase), high substrate loading decreased conversion yield. However, this was overcome if the enzyme was added between 12.5 and 20FPU g substrate(-1). Furthermore, this reaction condition facilitated continual stirring and enabled sequential additions (up to 50%w/v) of paper to be made to the hydrolysis reaction, degrading nearly all (99%) of the cellulose fibres and increasing the final concentration of glucose whilst simultaneously making high substrate concentrations achievable. Under optimal conditions (50°C, pH5.0, 72h), digestions facilitate the production of glucose to much improved concentrations of up to 1.33moll(-1).