Preliminary study for optimization of enzymatic hydrolysis of waste cellulosic materials

Abstract

Lignocellulose is a generic term describing the main constituents in most plants, namely cellulose, hemicelluloses, and lignin. Cellulose is a glucose polysaccharide, hemicelluloses are polysaccharides with a backbone of different hexoses (glucose, mannose, galactose) and pentoses (xylan, arabinose), and lignin is a complex network of different phenyl propane units. The cellulosic materials are potential sources of ethanol. Steps of this process are saccharification of cellulose to reduce sugars, under enzymes action and to reduce sugars fermentation by yeast to obtain ethanol. The aim of this study is to examine the influence of substrate concentration, temperature and pH upon enzymatic saccharification of waste cellulosic materials, based on office paper, newspaper and cardboard, in ratio of 1:1:1 (w/w) and reducing sugar accumulation dynamics in optimised conditions. The study has established optimal parameters: the ratio of enzyme:substrate as 0.5 EU/g substrate, temperature 48°C, pH 4.8 and addition of surfactant Tween 80 in proportion of 0.3 %, reported to the total volume of liquid. The reducing sugar yield was 35 mg reducing sugars/ g dry weight cellulosic waste.