The effect of orange peel concentration, HCl concentration, incubation time and temperature, and inoculum size on the spore count and activity of polygalacturonase (PG) enzyme produced from Aspergillus sojae M3 by solidstate fermentation was screened using 2k factorial design. | Turk J Biol 36 (2012) 394-404 © TÜBİTAK doi: Optimization of the process parameters for the utilization of orange peel to produce polygalacturonase by solid-state fermentation from an Aspergillus sojae mutant strain Hande DEMİR1, Nihan GÖĞÜŞ1, Canan TARI1, Doreen HEERD2, Marcelo Fernandez LAHORE2 1 Department of Food Engineering, İzmir Institute of Technology, Gülbahçe Campus, 35430 Urla, İzmir - TURKEY 2 Downstream Bioprocessing Laboratory, School of Engineering and Science, Jacobs University gGmbH, Bremen - GERMANY Received: ● Accepted: Abstract: The effect of orange peel concentration, HCl concentration, incubation time and temperature, and inoculum size on the spore count and activity of polygalacturonase (PG) enzyme produced from Aspergillus sojae M3 by solidstate fermentation was screened using 2k factorial design. Orange peel and HCl concentrations and incubation time were significant factors affecting the responses. Optimum conditions favoring both PG and spore production from Aspergillus sojae M3 were determined as 2% orange peel and 50 mM HCl concentrations at 22 °C and days of incubation. An overlay plot was constructed for use as a practical chart for production of high enzyme activity (> U/g substrate) and spore count ( × 108 to × 109 spore/mL) by superimposing the contours of PG activity and spore count responses. The accuracy and reliability of the constructed models on the responses was validated with the maximum calculated error rate between the predicted and actual activities at and , respectively. Key words: Aspergillus sojae, polygalacturonase, spore production, solid-state fermentation, orange peel, response surface methodology Introduction Enzymes are a key component in the textile, ethanol, and pharmaceutical industries as well as in the manufacture of food and beverages. Among food enzymes, pectinases are the complex and diverse group of enzymes that degrade pectic .
