Effects of Medium Composition and Process Parameters on the Production of Extracellular Inulinase by Thermomyces lanuginosus
Quang D. Nguyen*, Noémi M. Sujtó, Erika Bujna, Ágoston Hoschke and Judit M. Rezessy-Szabó
Department of Brewing and Distilling, Faculty of Food Science, Corvinus University of Budapest, Ménesi út 45, H-1118 Budapest, Hungary
Article history:
Received July 28, 2011
Accepted September 20, 2012
Key words:
inulinase, optimisation, thermophilic fungus, Thermomyces lanuginosus, response surface methodology
Summary:
The production of extracellular inulinase by eighteen Thermomyces lanuginosus strains was screened, and strain IMI 140524 was selected for further studies. The effects of various carbon and nitrogen sources on inulinase activity were investigated, and the best ones were found to be Jerusalem artichoke extract and peptone at the optimum fraction of 1.8 and 0.6 %, respectively. Effects of medium composition and fermentation conditions were also determined for the production of extracellular inulinase. The addition of 1 % (by volume) Tween 80 into fermentation medium enhanced the secretion of extracellular inulinase. In bench-scale fermentor, the age and amount of inoculum were also optimized and they were determined to be 40-hour-old culture and 5.0 % (by volume), respectively. The initial pH of the medium was adjusted to 6.5 and no further pH control was needed. Optimal aeration and agitation were 0.75 L/min and 150 rpm, respectively.
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