Production, characterization and applications of organic solvent tolerant lipase by Pseudomonas aeruginosa AAU2

Jatropha seedcake (JSC) represents an important environmental problem owing to its toxicity for the biodiesel producing sectors where they are generated in bulk as a major by-product. The aim of the present work was to study the feasibility of JSC as a substrate for lipase production under submerged condition. Pseudomonas aeruginosa AAU2 isolated from dumped rotting JSC was found to produce extracellular solvent tolerant lipase (0.432 U ml(-1)). A 11.4-fold increase in enzyme yield was obtained in an optimized medium containing 20 g JSC/I, 2.5 g potassium nitrate/I and 0.1 v/v% Tween 80 after 60 h of incubation at 30 C-circle under shake flask conditions (150 rpm). The pH and temperature optima of the partially purified AAU2 lipase were 7.5 and 40 C-circle, respectively. The AAU2 lipase was found to be a cysteine hydrolase and exhibited preference towards longer carbon chain fatty acid ester substrates over the shorter ones. The enzyme exhibited significant stability in the presence of commercial detergents namely, Ezee (R) and Wheel (R). The AAU2 lipase efficiently catalyzed biodiesel production using Jatropha oil. In addition, the enzyme also hydrolyzed 86.49% of commercially available phorbol ester (phorbol 12-myristate 13-acetate) within 12 h of incubation at 37 C-circle, suggesting its application in detoxification of phorbol ester from JSC. These results demonstrate viable approach for utilization of JSC biomass and degradation of phorbol esters by P. aeruginosa AAU2. (C) 2013 Elsevier Ltd. All rights reserved.