Effects of Medium Composition and Process Parameters on the Production of Extracellular Inulinase by Thermomyces lanuginosus

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