초록
<P><B>Abstract</B></P><P><I>Pseudomonas aeruginosa</I>strain BUP2 (MTCC No. 5924), a novel bacterium isolated from the rumen of the Malabari goat was explored in this study for its efficiency in the production of lipase in Benjamin Unni Priji medium supplemented with 1% groundnut oil. Plackett-Burman and Box-Behnken designs were applied for optimizing the culture parameters statistically for the enhanced production of lipase; and temperature (28°C), pH (6) and incubation time (24 h) were found as significant factors for increasing the production of lipase by 11% (from 152 to 171 U/mL). Using (NH<SUB>4</SUB>)<SUB>2</SUB>SO<SUB>4</SUB>fractionation and Sephadex G-100 gel filtration techniques, the lipase was purified to homogeneity (36 folds with 20% yield) with 2,392 U/mg specific activity; its apparent M<SUB>W</SUB>was 29 kDa, as judged by SDS-PAGE. The maximum activity (2,802 U/mL and 177% specific activity) of the purified lipase was observed with 50 mM<I>para</I>-nitrophenyl palmitate as substrate (at pH 8, 45°C temperature, 5.0 mM Ca<SUP>2+</SUP>and 0.5% Triton X-100, after 30 min of incubation). The<I>K</I><SUB>m</SUB>and<I>V</I><SUB>max</SUB>values of the purified lipase were found as 4.75 mM and 999 μmol/min/mg, respectively; and that this may be the first report on a lipase produced by a microorganism inhabiting the rumen of a goat. Briefly, the alkalophilic and thermotolerant lipase produced by<I>P. aeruginosa</I>strain BUP2 with higher specific activity would find better utility in detergency; moreover, this low M<SUB>W</SUB>protein is a good candidate for genetic engineering toward catalytic resolution of fine chemicals.</P>