Table of Contents
Biotechnology Research International
Volume 2011 (2011), Article ID 238549, 11 pages
http://dx.doi.org/10.4061/2011/238549
Research Article

Recovery of Bacillus licheniformis Alkaline Protease from Supernatant of Fermented Wastewater Sludge Using Ultrafiltration and Its Characterization

1INRS-ETE, Université du Québec, 490, Rue de la Couronne, QC, Canada G1K 9A9
2USEPA, P.O. Box-17-2141, Kansas City, Kansas, KS 66117, USA

Received 13 February 2011; Revised 30 April 2011; Accepted 3 May 2011

Academic Editor: Manuel Canovas

Copyright © 2011 Jyothi Bezawada et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

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°C and at pH 10. It was stable between pH 8 to 10 and retained 97% activity at 60°C 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.