Purification and characterization of extracellular lipases from Pseudomonas monteilii TKU009 by the use of soybeans as the substrate.

A lipase-producing bacterium was isolated and identified as Pseudomonas monteilii TKU009. A lipase (F2) and lipase-like materials (F1) were purified from the culture supernatant of P. monteilii TKU009 with soybean powder as the sole carbon/nitrogen source. The molecular mass of F1 and F2 was estimated to be 44 kDa by SDS-PAGE and gel filtration. The optimum pH, optimum temperature, and pH and thermal stabilities of F2 were 7, 40 degrees C, 8-11, and 50 degrees C; and of F1 were 6, 40 degrees C, 6-7, and 50 degrees C, respectively. F2 was completely inhibited by EDTA and slightly by Mg(2+), Fe(2+), Mn(2+), and SDS. F1 was completely inhibited by EDTA and Fe(2+) and strongly by Zn(2+), Mn(2+), Ca(2+), Mg(2+), and SDS. The activities of both the enzymes were enhanced by the addition of non-ionic surfactants Triton X-100 and Tween 40, especially for F1. F2 preferably acted on substrates with a long chain (C10-C18) of fatty acids, while F1 showed a broad spectrum on those with chain length of C4-C18. The marked activity of F2 in organic solvents makes it an ideal choice for application in a water-restricted medium including organic synthesis.