Biomass and Bioenergy 21 (2001) 109–120 Characterization and fermentation of steam exploded cotton gin waste T. Jeoh, F.A. Agblevor ∗ Department of Biological Systems Engineering, Virginia Polytechnic Institute and State University, 212 Seitz Hall, Blacksburg, VA 24061-0303, USA Received 19 June 2000; accepted 16 March 2001 Abstract Cotton gin waste was collected from a cotton ginning plant in Virginia and characterized before and after steam explosion to evaluate its potential applications for higher value products such as ethanol. The raw cotton gin waste had high levels of ash (10:5 wt%) and acid insoluble material (28:8 wt%). The xylan and cellulose contents were, respectively, 9 and 37 wt%. The cotton gin waste was steam exploded in a batch gun at severities ranging from 2 to 4.9. Substantial solubilization= degradation of ber material (9–17 wt%) occurred during steam explosion pretreatment especially at the high severities. Mannan, galactan, and arabinan were completely solubilized= degraded at severities greater than 3.56. Both glucan and xylan were solubilized= degraded at all severities, but xylan loss was considerably higher. The steam exploded material was essentially cellulose and acid insoluble material and small fractions of xylan at severities greater than 3.56. Steam explosion improved the enzyme hydrolysis of the material from 42% to 67% during 24 h incubation. E. coli KO11 was eective in converting the enzyme hydrolyzed substrate to ethanol. The highest ethanol yield (83% of theoretical yield) was achieved for material treated at a severity of 3.56. Both xylose and glucose were fermented to ethanol by the microorganism. c  2001 Elsevier Science Ltd. All rights reserved. Keywords: Cotton gin waste; Steam explosion; Pretreatment; Cellulose; Enzyme hydrolysis; Fermentation; E. coli KO11 1. Introduction Renewable energy technologies are of interest to the agro-based industries because they produce sev- eral million tons of waste material, which have to be disposed either through incineration, land applications * Corresponding author. Tel.: +1-540-231-2578; fax: +1-540- 231-3199. E-mail address: fagblevo@vt.edu (F.A. Agblevor). or landlling. However, because of the increasing tipping fees and stricter regulations on particulate emissions due to the Clean Air Act, there is renewed interest in producing value-added products from these raw materials. In the cotton industry, the ginning pro- cess generates a considerable amount of waste, which was previously disposed by combustion. For small cotton ginning plants, the cost of retrotting their fa- cilities to meet new particulate emission standards is prohibitive [1]. 0961-9534/01/$ - see front matter c  2001 Elsevier Science Ltd. All rights reserved. PII:S0961-9534(01)00028-9