Treatment of Waste Paper Using Ultrasound and Sodium Hydroxide for Bioethanol Production

Abstract

Bioethanol produced from lignocellulose feedstock is a renewable substitute to declining fossil fuels. Pretreatment using ultrasound assisted alkaline was investigated to enhance the enzyme digestibility of waste paper. The pretreatment was conducted over a wide range of conditions including waste paper concentrations of 1-5%, reaction time of 10-30 min and temperatures of 30-70°C. The optimum conditions were 4 % substrate loading with 25 min treatment time at 60°C where maximum reducing sugar obtained was 1.89 g/L. Hydrolysis process was conducted with a crude cellulolytic enzymes produced by Cellulomonas uda (PTCC 1259).The maximum amount of sugar released and hydrolysis efficiency were 20.92 g/L and 78.4 %, respectively. Sugars released from waste paper were fermented into bioethanol with Saccharomyces cerevisiae. The maximum concentration of bioethanol estimated was 9.5 g/L after 48h of cultivation, the yield and volumetric productivity were 0.454 g/g glucose and 0.2g bioethanol/ L h. respectively. This study of ultrasound and sodium hydroxide treatment may be (we think) it will be a promising technique to develop bioethanol production from waste paper.

On the Conversion of Paper Waste and Rejects into High-Value Materials and Energy

“…Bioethanol is the only fuel so far that can be transported in liquid form and does not release greenhouse gases into the atmosphere when burned as the CO 2 emitted is used up by plants in photosynthesis as long as the biofuel consumption rate is not more than the photosynthesis rate [87]. First-generation bioethanol is produced from sugar and starch, whereas second-generation bioethanol is produced from waste containing lignocellulose.…”

“…Most of the processes that are used currently for bioethanol production from biomass involve certain pretreatments before hydrolysis and fermentation. Pretreatments include the usage of acid, alkali, or other organic solvents, and choosing the correct pretreatment is crucial in bioethanol production as it affects the cellulose conversion rates and enzyme activity [87]. Pretreatment is essential to gain good yields of sugars from cellulose and hemicellulose, and it increases the digestibility of cellulosic biomass [92].…”