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Pak. J. Bot., 47(4): 1521-1526, 2015.

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BIOSYNTHESIS, PURIFICATION AND CHARACTERIZATION OF COMMERCIAL ENZYME BY PENICILLIUM EXPANSUM LINK

KASHIF AHMED¹, EHSAN ELAHI VALEEM², QAMAR-UL-HAQ³

Abstract: Ever growing biotechnological industry has motivated the research towards the comprehensive survey of microorganisms, which could be used in extreme conditions of industry. In the present work optimization parameters in submerged fermentation, purification and characterization of invertase from Penicillium expansum Link using agricultural wastes (sunflower waste, cotton stalk and rice husk) as well as agro-industrial wastes (date syrup and molasses) as sources of carbon. Maximum production of invertase (7.03 U/mL) was observed when the strain was grown on culture medium (CM1) containing yeast extract as a source of nitrogen, date syrup as a source of carbon after 48 h of incubation at initial pH 5.0, temperature 35ºC, inoculum size of 6x10⁶ conidia in 50 mL of culture medium and agitation rate of 150 rev/min. After optimization the enzyme was also purified partially and then characterized. Kinetic constants (K_m 2.57 mM and V_max 178.6 U/mL/min) were determined by Lineweaver-Burk Plot and molecular mass (110 kDa) by 10% SDS-PAGE. Invertase showed maximum activity at pH 5.5 (128.7 U/mL) and at the temperature of 60ºC (114.6 U/mL). BaCl₂ (21.9%)_, MgSO₄ (42.6%), MnCl₂ (46.8%) and   EDTA (8.3%) enhanced the relative activity of enzyme while HgCl₂ (-90.9%), CuSO₄ (-82.3%) and CuCl₂ (-78.7%) were proved inhibitors.

Key words: Invertase, Submerged fermentation, Commercial enzyme.

¹Department of Chemistry, N.E.D. University of Engineering & Technology, Karachi, Pakistan

²Institute of Marine Science, University of Karachi, University Road, Karachi-75270, Pakistan

³ Federal Urdu University of Arts, Science and Technology, Gulshan-e-Iqbal, Karachi, Pakistan

Corresponding author e-mail: kashif25473@yahoo.com