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Pak. J. Bot., 47(3): 1121-1127, 2015.

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PRODUCTION OF RENNIN-LIKE ACID PROTEASE BY MUCOR PUSILLUS THROUGH SUBMERGED FERMENTATION

SUNILA DAUDI, HAMID MUKHTAR*, ASAD-UR-REHMAN AND IKRAM-UL-HAQ

Abstract: The present study is concerned with the isolation and screening of Mucor species for the production of acid protease in shake flasks. Out of eight mould cultures evaluated, five were isolated from soil and three were provided from the Institute of Industrial Biotechnology, Government College University, Lahore. Of all the isolates tested, Mucor pusillus IHS₆ was found to be the best producer of rennin-like acid protease producing 75 U/ml of the enzyme. Different agricultural byproducts were evaluated as fermentation substrates and maximum enzyme synthesis (61 U/ml) was obtained when rapeseed meal was used as a substrate. Optimum pH and fermentation period for the production of protease were 5.5 (56U/ml) and 72 hrs (55U/ml), respectively. The production of protease by Mucor pusillus IHS₆ was also studied by adding different carbon and nitrogen sources to the fermentation medium. Fructose at a concentration of 1.5% (66 U/ml) and yeast extract at a concentration of 2% (68.2 U/ml) and ammonium chloride at a concentration of 0.1% (67U/ml)  were found to be the best carbon and nitrogen (organic and inorganic) sources respectively. Spore inoculum at a concentration of 1% (68.4 U/ml) was found to be the best for protease production by Mucor pusillus. The fermentation broth was found to have strong milk clotting activity with 200 RU.

Key words: Milk clotting, Cheese, Protease, Fungi, Rennet.

Institute of Industrial Biotechnology, Government College University, Lahore-54000, Pakistan

*Corresponding Author’s email: hamidmukhtar@gcu.edu.pk