Bioethanol production from waste paper acid pretreated hydrolyzate with xylose fermenting Pichia stipitis

This study evaluates acid pretreated waste paper hydrolyzate as feedstock for bioethanol production. The presence of 70.12 +/- 4.88% carbohydrates (holocellulose) makes waste paper a prospective and renewable biomass for bioethanol production. The waste paper was found to contain a-cellulose (61.5 +/- 3.49%), pentosans (7.42 +/- 0.36%), lignin (16.33 +/- 0.96%), ash (12.50 +/- 0.33%) and moisture (8.28 +/- 0.63%). Conditions for the dilute acid pretreatment of waste paper were optimized by varying solid/liquid ratio 1:8-1:14 (w/v), reaction time 01-06 h, and sulfuric acid concentration 0.005-1.00 N at 120 degrees C in an autoclave. The conditions optimized for acid hydrolysis of waste paper were 0.50 N H2SO4 at 120 degrees C for 02h reaction time keeping biomass:acid ratio 1:10 (w/v) for recovery of reducing sugars from waste paper hydrolyzate. Fermentation of acid hydrolyzate of waste paper with Pichia stipitis under optimum condition resulted in ethanol production 3.73 +/- 0.16 g/l with 77.54 +/- 4.47% of fermentation efficiency. (C) 2012 Elsevier Ltd. All rights reserved.