%0 Journal Article
%T Recovery of Bacillus licheniformis Alkaline Protease from Supernatant of Fermented Wastewater Sludge Using Ultrafiltration and Its Characterization
%A Jyothi Bezawada
%A S. Yan
%A Rojan P. John
%A R. D. Tyagi
%A R. Y. Surampalli
%J Biotechnology Research International
%D 2011
%I Hindawi Publishing Corporation
%R 10.4061/2011/238549
%X Investigation on recovery of alkaline protease from B. licheniformis ATCC 21424 fermented wastewater sludge was carried out by centrifugation and ultrafiltration. Optimization of ultrafiltration parameters (transmembrane pressure (TMP) and feed flux) was carried out with 10£¿kDa membrane. TMP of 90£¿kPa and feed flux of 714£¿L/h/m2 gave highest recovery (83%) of the enzyme from the centrifuged supernatant. The recovered enzyme had given maximum activity at temperature of 60¡ãC and at pH 10. It was stable between pH 8 to 10 and retained 97% activity at 60¡ãC after 180£¿min of incubation. Enzyme activity was significantly augmented by metal ions like Ca2+ and Mn2+. Protease inhibitors like phenylmethyl sulphonyl fluoride (PMSF) and diisopropyl fluorophosphates (DFPs) completely inhibited the enzyme activity. The partially purified protease showed excellent stability and compatibility with various commercial detergents. The detergent (Sunlight) removed the blood stains effectively along with the enzyme as additive. 1. Introduction The membrane separation processes are the most widespread in the field of biotechnology, and they are more easily operated and scaled up in comparison to other bioseparation processes such as chromatography, and electrophoresis. Among the various membrane separation processes, ultrafiltration is one of the processes that functions under pressure gradient which is mostly used for separation and purification of products including enzymes and other proteins [1¨C3] or to recover microbial products (cells and spores) present in a culture medium [4¨C6]. Because of the low amount of enzyme present in the cell-free filtrate, the water removal is a primary objective. Ultrafiltration is an effective technique that has been largely used for the recovery of enzymes [7, 8] and, in general, is a preferred alternative to evaporation. This pressure driven separation process is not expensive and also gives encouraging results with little loss of enzyme activity. This process offers both concentration and purification [9]. However, the application of membrane processes in general have some specific problems like fouling or membrane clogging due to the precipitates formed by the final product and/or deposition of solid particles on the membrane. If the solute flow towards the membrane is greater than the solute passing through the membrane, the solute accumulates on the surface of the membrane, this accumulation forms a concentration layer which is known as concentration polarization [10]. Tangential flow filtration is powerful and advantageous alternative
%U http://www.hindawi.com/journals/btri/2011/238549/