ORIGINAL PAPER Optimization of amylase production by Aspergillus niger in solid-state fermentation using sugarcane bagasse as solid support material Renato Pe ´rez Rose ´s Æ Nelson Pe ´rez Guerra Received: 8 February 2009 / Accepted: 15 June 2009 / Published online: 28 June 2009 Ó Springer Science+Business Media B.V. 2009 Abstract Synthesis of amylase by Aspergillus niger strain UO-01 under solid-state fermentation with sugarcane bagasse was optimized by using response surface meth- odology and empirical modelling. The process parameters tested were particle size of sugarcane bagasse, incubation temperature and pH, moisture level of solid support material and the concentrations of inoculum, total sugars, nitrogen and phosphorous. The optimum conditions for high amylase production (457.82 EU/g of dry support) were particle size of bagasse in the range of 6–8 mm, incubation temperature and pH: 30.2°C and 6.0, moisture content of bagasse: 75.3%, inoculum concentration: 1 9 10 7 spores/g of dry support and concentrations of starch, yeast extract and KH 2 PO 4 : 70.5, 11.59 and 9.83 mg/ g of dry support, respectively. After optimization, enzyme production was assayed at the optimized conditions. The results obtained corroborate the effectiveness and reliabil- ity of the empirical models obtained. Keywords Amylase  Optimization  Solid-state fermentation  Sugarcane bagasse Abbreviations RSM Response surface methodology SLF Submerged liquid fermentation SSF Solid-state fermentation gds g of dry support TAA Total amylase activity EU Enzymatic units T Temperature IC Inoculum concentration M Moisture content TS Total sugars concentration N Nitrogen concentration P Phosphorous concentration Introduction The Aspergillus species produce a large variety of extra- cellular enzymes of which amylases are of world-wide interest in fermentation, food, pharmaceutical, textile and paper industries (Bhargav et al. 2008; Uma Maheswar Rao and Satyanarayana 2007). Production of amylases by Aspergillus strains in both submerged liquid fermentation (SLF) and solid-state fermentation (SSF) by using different food wastes or agricultural residues has been thoroughly studied (Ellaiah et al. 2002; Francis et al. 2002, 2003; Murado et al. 1997; Salas et al. 2006). However, compar- ative studies between SLF and SSF claim higher yields and other advantages for products obtained by SSF, such as low energy requirements, lower availability of water that reduces the possibilities of contamination by bacteria and yeast, small volumes of polluting effluents and low downstream processing cost (Guerra et al. 2003; Raimbault 1998). The production of amylases in SSF is affected by a variety of physicochemical factors, including the type and nutrient composition of the substrate, incubation temperature, pH, R. P. Rose ´s Department of Pharmacy, Natural Science Faculty, University of Oriente, Santiago de Cuba, Cuba N. P. Guerra (&) Nutrition and Bromatology Group, Department of Analytical and Food Chemistry, Food Science and Technology Faculty, Ourense Campus, University of Vigo, As Lagoas, 32004 Ourense, Spain e-mail: nelsonpg@uvigo.es 123 World J Microbiol Biotechnol (2009) 25:1929–1939 DOI 10.1007/s11274-009-0091-6