Industrial Crops and Products 31 (2010) 277–283 Contents lists available at ScienceDirect Industrial Crops and Products journal homepage: www.elsevier.com/locate/indcrop Optimization of cellulase production by a versatile Aspergillus fumigatus fresenius strain (AMA) capable of efficient deinking and enzymatic hydrolysis of Solka floc and bagasse Rohit Soni, Asiya Nazir, B.S. Chadha ∗ Department of Microbiology, Guru Nanak Dev University, Amritsar 143005, India article info Article history: Received 10 September 2009 Received in revised form 30 October 2009 Accepted 5 November 2009 Keywords: Solid-state fermentation Box–Behnken design Cellulase and xylanase production Deinking Saccharification abstract This study reports the optimization of cellulase production by a versatile Aspergillus fumigatus fresenius (AMA) strain capable of efficient deinking and enzymatic hydrolysis of Solka floc and bagasse. The cul- ture produced maximal levels of cellulase on basal salt medium containing rice straw as carbon and beef extract as nitrogen source at 45 ◦ C. Further optimization of enzyme production was carried out using Box–Behnken design of experiment to study the influence of process variables (beef extract, temper- ature and tween 80) on cellulase and xylanase production. The model computed for R 2 value ranged between 95.3% and 99.9% indicating that they are appropriate and can be useful to predict the level of beef extract, temperature and tween 80 required to achieve optimal cellulase production by A. fumigatus fresenius (AMA). The culture under optimized conditions produced 240.2, 9.73, 470, 15, 2800 (units/g of substrate) of endoglucanase, Fpase, -glucosidase, cellobiohydrolase (CBH) and xylanase correspond- ing to 2.45, 2.88, 2.13 and 1.29 folds improvement, respectively, in enzyme activities when compared to those obtained under unoptimized conditions. The treatment of composite paper pulp with enzyme extracts (@ 0.5 U CMCase/g pulp) for 30 min resulted in 53% removal of ink and increased the brightness of the hand sheets by 4.32% ISO. The concentrated culture extracts from A. fumigatus fresenius also effi- ciently hydrolyzed Solka floc SW 40 and bagasse (@ 7%, w/v) resulting in 90 and 87% saccharification, respectively. © 2009 Elsevier B.V. All rights reserved. 1. Introduction Cellulases are important glycosyl hydrolases that are involved in degrading on and recycling the abundant cellulosic biomass in nature. From biotechnological standpoint, cellulases have a vital role to play in the generation of potentially sustainable energy sources such as glucose, ethanol, hydrogen and methanol (Kamm and Kamm, 2004; Zang and Lynd, 2005). Cellulases are produced by a variety of microorganisms including bacteria, actinomycetes and fungi. Fungi, however, are known to secrete cellulases in large amounts. Cellulase is a complex of enzyme system comprising of endoglucanase (EC 3.2.1.4), exoglucanase (EC 3.2.1.91) and - glucosidase (EC 3.2.1.21) that act in a synergistic fashion to carry out the complete hydrolysis of cellulose. Endoglucanase acts internally on the chain of cellulose cleaving 1,4--linked bonds and liberating oligosaccharides of varying degrees of polymerization. The exoglu- canases act processively from reducing and non-reducing ends removing cellobiose in a sequential manner. Finally, -glucosidase ∗ Corresponding author. Tel.: +91 183 2258802 09x3317; fax: +91 183 2258820. E-mail address: chadhabs@yahoo.com (B.S. Chadha). completes the saccharification by splitting cellobiose and small cello-oligossaccharides into glucose molecules (Wither, 2001). Cur- rently, cellulases have gained significant commercial importance due to their potential application in deinking of mixed office waste (MOW), magazines and newspapers, denim stone washing, etc. (Cavaco-Paulo, 1998; Soni et al., 2008; Vyas and Lachke, 2003). In addition, cellulases along with hemicellulases in the enzyme cocktails have the great potential in the saccharification of lignocel- lulosics to fermentable sugars, and perhaps the most sought after application for its role in bioconversion of cellulosics to ethanol (Elegir et al., 2000). The application of cellulases in these processes are carried out at relatively higher temperatures (∼50–60 ◦ C) and therefore those enzymes are preferred that are capable of withstanding high temperature for a longer period of time. The thermophilic and ther- motolerant fungi are known to thrive at high temperature and produce appreciable levels of thermostable enzymes that are suit- able for these applications (Maheshwari et al., 2000; Sharma et al., 2008). This paper reports cellulase production by Aspergillus fumigatus fresenius (AMA) strain isolated from the degrading paper/polythene composite waste. The strain was found to pro- duce an endoglucanase devoid of cellulose binding domain (CBD) 0926-6690/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.indcrop.2009.11.007