The production of an extracellular lipase using corn steep liquor (CSL) as the nitrogen source in the cultivation of Geotrichum candidum NRRLY‐552 was evaluated. The optimized conditions in shake flasks were CSL, 8.0 % w/v, soybean oil, 0.6 % w/v, pH 7.0, 30 °C, 250 rpm, and 48 h, resulting in a maximum lipase productivity of 0.438 U mL−1 h−1(U = the amount of enzyme required to liberate 1 μmol of fatty acid per minute). Scale‐up was evaluated with airlift and stirred tank reactors; the best conditions, respectively, were 1 vvm(volume of gas per volume of medium per minute) of aeration which resulted in 0.535 U mL−1 h−1 (32 h) and 1 vvm and 300 rpm resulting in 0.563 U mL−1 h−1 (16 h). To facilitate downstream processes, lipase production was also evaluated using CSL previously clarified with activated charcoal resulting in 0.275 U mL−1 h−1 (24 h) using 12 % (w/v) of clarified CSL in shake flasks. The obtained results showed that CSL leads to similar productivity compared to peptone using the same microorganism under similar conditions. In addition the cost of fermentation medium using CSL is much lower because it is a very inexpensive by‐product from corn processing.

Lipase production by Geotrichum candidum NRRL Y-552 was studied using an alternative nitrogen source, yeast hydrolysate (Prodex-lac 1 ), and soybean oil as the carbon source and inducer of lipase production. Factorial design and response surface methodologies were applied to obtain optimized conditions for lipase production in shaken flasks, defined as: 3.5 g/100 mL of yeast hydrolysate and 0.7 g/100 mL of soybean oil with an initial pH of 7.0 at 30 8C and 250 rpm. The resulting lipase activity after 48 h was 24.3 U/mL (0.506 U/mL . h), 52 % higher than with peptone under the same conditions (U ¼ the amount of enzyme required to liberate 1 mmol of fatty acid per minute). Lipase production with the optimized medium was conducted in a stirred tank reactor and in an airlift bioreactor, both at 30 8C and 300 rpm; the best results obtained were 15.4 U/mL after 32 h of fermentation (0.481 U/mL.h) and 19.24 U/mL after 32 h of fermentation (0.601 U/mL . h) at 1 vvm, respectively. The results presented here from both bioreactors showed similar results to a previous study with the same microorganism under the same conditions using peptone as a nitrogen source. In addition, yeast hydrolysate is a cheaper nitrogen source than peptone and yeast extract, which permits a cost reduction above 90 % under similar conditions.

same catalytic efficiency (K m /k cat = 32.12 mg mL min −1 ) in relation to CCSL crude lipase. The lipases differ in biocatalytic properties between substrates, suggesting that the two lipases can be employed for different applications.