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Title: Production, characterization, and potential application of a keratinolytic alkaline protease produced by alkaliphilic Vibrio sp.
Authors: Muhammed, Seid
Advisors: Amare Gessesse (Ph.D)
Keywords: Dehairing
Gelatin hydrolysis
Hair degrading
Keratinolytic protease
Keratinous wastes;
Used x-ray film
Vibrio sp. strain R11
Copyright: May-2011
Date Added: 5-Jul-2012
Publisher: Addis Ababa University
Abstract: At present alkaline proteases are widely used in leather processing, detergent formulations, silver recovery process, and in the production of protein hydrolysates. All alkaline proteases are dervied from microbial sources that grow on expensive growth substrate. Many studies showed that nearly 40% of the production cost of alkaline proteases is accounted for by the growth substrate. To reduce the production cost it is important to search for microorganisms capable of growing and producing suffiecient amount of the enzyme using cheap substartes. In this regard keratinacious wastes released by poultry and leather tanning industries has an enourmous potential to serve as growth substartes for protease production. In this study, a protease producing Vibrio sp. capable of growing on bovine and sheep hair was isolated from Lake Arenguade. The organism produced appreciable level of keratinolytic protease using hair as the sole source of carbon and nitrogen. The enzyme was active in the pH range of 7.0- 11.5 and 40-70°C with an optimum pH of 11.0 and 50oC. The enzyme showed good stability in the presence of oxidizing agents and detergents. Application of the enzyme at the inner side sheep skin at a dosage of 58U/ml, pH 10.0 brought about complete removal of hair within 24 h at room temperature and 12 h at 37oC. Protease R-11 was also tested for the recovery of silver from used x-ray films. At enzyme dose of 11.6 U/ml and at 55oC complete removal of the gelatin layer of used x-ray films was achieved within 3 min at pH 10.00. These results indicate the potential of protease R-11 for multipurpose industrial application. Because the organism produces the enzyme using cheap substrates, hair, its production cost is expected to be very low.
Description: A Thesis Submitted to the School of Graduate Studies Addis Ababa University In Partial Fulfillment of the Requirement for the Degree of Master of Science in Biotechnology
URI: http://hdl.handle.net/123456789/3279
Appears in:Thesis - Biology

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