Elucidation of the effects of inoculum size and age on lipase production by Geotrichum candidum

Lipases are extremely versatile enzymes with large industrial applications and they have been the subject of investigation over the last few years. A great variety of microorganisms can produce this enzyme, such as pluricellular fungi, but their growth need to be optimized due to the variations amongst experiments, which influence the results and reproducibility of the process. The aim of this work was to study the best conditions for inoculum size and age of Geotrichum candidum NRRLY-552, to reduce the variability of the inoculum. The optimized inoculum procedure was determined as: 1 circular area (0.79 cm2) of the solid medium containing cells and spores added to 100 mL of culture medium (5.0 % w/v of peptone, 0.1 % w/v of NaNO3, 0.1 % w/v of MgSO4 and 1.0 % w/v of soybean oil) incubated for 15 h at 30 °C, 250 rpm and with an initial pH of 7.0. This procedure permitted to reduce the experimental error from 30 to 20 % and it has been applied successfully in different studies since then.