Bioresource Technology 98 (2007) 1947–1950 0960-8524/$ - see front matter  2006 Published by Elsevier Ltd. doi:10.1016/j.biortech.2006.07.047 DetoxiWcation of sugarcane bagasse hydrolysate improves ethanol production by Candida shehatae NCIM 3501 Anuj Kumar Chandel a , Rajeev Kumar Kapoor a , Ajay Singh b , Ramesh Chander Kuhad a,¤ a Lignocellulose Biotechnology Laboratory, Department of Microbiology, University of Delhi South Campus, Benito Juarez Marg, New Delhi 110 021, India b Department of Biology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 Received 24 April 2006; received in revised form 20 July 2006; accepted 21 July 2006 Available online 2 October 2006 Abstract Sugarcane bagasse hydrolysis with 2.5% (v/v) HCl yielded 30.29 g/L total reducing sugars along with various fermentation inhibitors such as furans, phenolics and acetic acid. The acid hydrolysate when treated with anion exchange resin brought about maximum reduc- tion in furans (63.4%) and total phenolics (75.8%). Treatment of hydrolysate with activated charcoal caused 38.7% and 57.5% reduction in furans and total phenolics, respectively. Laccase reduced total phenolics (77.5%) without aVecting furans and acetic acid content in the hydrolysate. Fermentation of these hydrolysates with Candida shehatae NCIM 3501 showed maximum ethanol yield (0.48 g/g) from ion exchange treated hydrolysate, followed by activated charcoal (0.42 g/g), laccase (0.37 g/g), overliming (0.30 g/g) and neutralized hydroly- sate (0.22 g/g).  2006 Published by Elsevier Ltd. Keywords: Candida shehatae; Acid hydrolysis; DetoxiWcation; Ethanol; Laccase 1. Introduction Lignocelluloses are the largest source of hexose and pentose sugars with potential use for the production of fuel alcohol, chemicals and protein for food and feed purpose (Kuhad and Singh, 1993; Kuhad et al., 1997; Herrera, 2004). Amongst the various agricultural crop res- idues, sugarcane bagasse is the most abundant agricul- tural material in India and has a production rate of 179 metric tones/year on an average, second after Brazil (Kapoor et al., 2006). The cellulosic and hemicellulosic fractions can be hydrolyzed to sugars, which eventually could be fermented to ethanol. Thermochemical pretreat- ment disrupts the lignocellulosics and partially solubilize polysaccharides to release the fermentable sugars (Gray et al., 2006). The ideal organism for the production of ethanol would be the one, which can utilize pentose and hexose sugars generated by lignocellulose hydrolysis. The best-known alcohol fermenting organism, Saccharomyces cerevisiae is capable of fermenting only hexose sugars to ethanol. However, pentose fermenting organisms are lim- ited. Of various xylose fermenting yeasts, Candida sheha- tae is promising one for ethanol production from acid, auto and enzymatic hydrolysates from lignocellulosics (Abbi et al., 1996b). Dilute acid hydrolysis is a fast and easy method to per- form but it is hampered by non-selectivity and byproduct formation (Gray et al., 2006). During acid hydrolysis of lignocellulosics, in addition to the sugars, aliphatic acids (acetic, formic and levulinic acid), furan derivatives furfural and 5-hydroxymethylfurfural (HMF), and phenolic com- pounds are formed. These compounds are known to aVect ethanol fermentation performance (Larsson et al., 1999). Several detoxiWcation methods like neutralisation, over- liming with calcium hydroxide, activated charcoal, ion exchange resins (Carvalheiro et al., 2005) and enzymatic detoxiWcation using laccase (Jönsson et al., 1998) are * Corresponding author. Tel.: +91 09871509870/11 24112972; fax: +91 11 24115270. E-mail address: kuhad@hotmail.com (R.C. Kuhad).