PJB-2013-98
A COMPARATIVE STUDY OF NUTRITIONAL AND ENVIRONMENTAL FACTORS AFFECTING EXTRACELLULAR AND INTRACELLULAR INVERTASE PRODUCTION IN CANDIDA UTILIS
FATIMA ZAFAR QURESHI AND AAFIA ASLAM*
Abstract
Twenty-five strains of Candida utilis were isolated from various varieties of Vitis vinifera (black grapes), obtained from the local markets of Lahore. Strain KC-B10 showed maximum enzyme activity. Five media, M1, M2,M3, M4 and M5 were screened for enzyme activity with KC-B10 M1 showed maximum invertase activity i.e. 25.2 ± 0.20 U/ml extracellular invertase, 21.5 ± 0.40 U/ml intracellular invertase activity and dry cell mass 5.53 ± 0.03 g/l. The nutritional and environmental conditions were optimized for this medium using shake flask fermentation technique. After optimization of cultural conditions, the maximum enzyme activity of intracellular invertase (30.4 ± 0.47 U/ml) and extracellular invertase (49.4 ± 0.20 U/ml) with dry cell mass of 6.19 ± 0.01 g/l at 24 hrs incubation time, 1.6% (w/v) sucrose concentration, 1% yeast extract, pH 4, 30°C temperature and 200 rpm agitation rate. An increase of 49% was observed in extracellular activity while an increase of 30% was observed in intracellular activity with an increase of 10% dry cell mass. Invertase finds its uses in the confectionary and pharmaceutical industries. This study indicates that single organic source of nitrogen with a single carbon source and no other supplements are required for the optimum production of both types of invertases from Candida utilis KC-B10. Thereby resulting in the formation of an economically friendly optimized medium for production of invertases in Pakistan, a third world country with a fast growing population and limited resources.
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