Paper sludge is a solid residue in paper making process that is currently disposed in land fields or burned. That consequently pollutes the environment and on the other hand this waste could be potentially valuable bioenergy convertible resource. Paper sludge, which contains cellulosic and lignocellulosic residues, is believed to be one of the most promising feedstock for the production of bio-ethanol. Bio-ethanol is the most employed liquid biofuel either as a fuel or as a gasoline enhancer. Production of ethanol for fuel is increasing because of the demand to reduce oil consumption and improving air quality, which is related to reduced emission of CO and aromatic compounds.
The main processing challenge in the ethanol production is the pretreatment of lignocellusosic biomass. During the pretreatment the degree of crystallinity of cellulose must be reduced to increase the fraction of amorphous cellulose, which is amenable to enzymatic hydrolysis. For the pretreatment one can employ physical, chemical and biological methods. The pretreatment method should improve following formation of glucose and avoid the formation of inhibitors for subsequent hydrolysis and fermentation processes.
In this study paper sludge from paper making company was firstly pretreated by milling or using phosphoric acid (H3PO4) and then enzymatically treated with enzyme cellulase. Enzymatic hydrolysis of cellulose using cellulase converted it to glucose. Hydrolyses were conducted at temperature, ?? = 45 ºC, stirrer speed, fm = 200 min-1, different range of pH = (4 - 6) and amount of enzyme V = (100, 500, 1,000, 2,000 and 3,000) µL. We achieved the conversion of more than 83 % after 48 h hydrolysis at pH = 5 and amount of enzyme V = 3,000 µL.