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°C, 8–11,
and 50°C; and of F1 were 6, 40°C, 6–7, and 50°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.
Keywords
Pseudomonas monteilii
- Alkaline lipase - Soybeans - Purification
Li-June Ming is a visiting Professor at the National Cheng Kung University.