Improvement of lipase production at different stirring speeds and oxygen levels

Abstract

-Lipase production by a Brazilian wild strain of Yarrowia lipolytica at different stirring speeds and air flow rates was studied. The relationship among lipid consumption, cell growth and lipase production by this microorganism is presented. The most pronounced effect of oxygen on lipase production was determined by stirring speed. Maximum lipase activity was detected in the late stationary phase at 200 rpm and an air flow rate of 1-2 dm 3 /min (0.8-1.7 vvm) when the lipid source had been fully consumed. Higher stirring speeds resulted in mechanical and/or oxidative stress, while lower stirring speeds seemed to limit oxygen levels. An increase in the availability of oxygen at higher air flow rates led to faster lipid uptake and anticipation of enzyme release into the culture medium. The highest lipase production was obtained at 200 rpm and 1 dm 3 /min (0.8 vvm).

A comprehensive study of lipase production byYarrowia lipolyticaCECT 1240 (ATCC 18942): from shake flask to continuous bioreactor

“…These culture times were similar to those reported for maximum lipase production by Y. lipolytica IMUFRJ 50 682, 7,15 but further shortening of the required culture times would be desirable.…”

Yarrowia lipolytica: A model microorganism used for the production of tailor‐made lipids

“…Results of the same magnitude with the ACA-DC 50109 strain (e.g., 2.5-8.5 U/ mL) have been achieved by Pereira-Meirelles et al [87,88]. Additionally, lipase production was critically influenced by the addition of various nutrients and surfactants to the medium, the agitation and aeration rates imposed, and the utilization of perfluorocarbons as oxygen carriers [89][90][91][92]. Kamzolova et al [93] have reported lipase activities higher than that of the strain ACA-DC 50109 (e.g., 1.8-45.5 U/ mL).…”

Industrial derivative of tallow: a promising renewable substrate for microbial lipid, single-cell protein and lipase production by Yarrowia lipolytica

“…Pereira-Meirelles et al (1997) reported maximum lipase concentrations around 2.5-3.0 IU/ml by a wild C. lipolytica strain cultivated on media containing olive oil and peptone, while higher quantities of total (extra-cellular and cell-bound) lipase were obtained in media enriched with both yeast extract and peptone (5.0-8.5 IU/ml) (Pereira-Meirelles et al 2000). Additionally, lipase production was lowered when the agitation rate in the medium increased (Alonso et al 2005). Kamzolova et al (2005) screened a huge number of Y. lipolytica strains and reported lipase activities ranging from 1.8-45.5 IU/ml.…”

“…The above findings support the potential of the microorganism for the biotechnological valorisation of saturated waste fats and the production of single-cell protein from fatty materials. In the literature, it is suggested that yield Y X/S values of around 0.9 ± 0.2 g/g are very satisfactory for single-cell protein fermentation from fatty substrates (Aggelis et al 1997;Alonso et al 2005) with lower Y X/S values (e.g. 0.5-0.7 g/g) obtained for high-lipase producing wild Y. lipolytica strains (Dominguez et al 2003;Kamzolova et al 2005).…”

“…urea, peptone or yeast extract) (Adamczak and Bednarski, 1996;Pereira-Meirelles et al 1997;Pereira-Meirelles et al 2000;Dominguez et al 2003;Fickers et al 2004;Fickers et al 2005a;Fickers et al 2005b). Lipase production is also critically affected by the presence of surfactants and the aeration and the agitation of the culture medium, and with wild Y. lipolytica strains, quantities ranging from 1.0 up to 58.5 IU/ml (1 IU defined as the quantity of the enzyme required for the liberation of 1 µmol of fatty acid per min) have been achieved (Dominguez et al 2003;Alonso et al 2005;Kamzolova et al 2005). Additionally, genetic engineering or mutagenesis have been employed in order to improve lipase production, and after extensive selection of new over-producing genetically engineered derivatives and optimisation of culture conditions, the concentrations have been remarkably ameliorated (Nicaud et al 2002;Fickers et al 2004;Fickers et al 2005b).…”