Effects of oxygen volumetric mass transfer coefficient and pH on lipase production by Staphylococcus warneri EX17

Abstract

The principal objectives of this study were to evaluate the kinetics of lipase production by Staphylococcus warneri EX17 under different oxygen volumetric mass transfer coefficients (k L a) and pH conditions in submerged bioreactors, using glycerol (a biodiesel by-product) as a carbon source. Cultivations were conducted at different k L a (26, 38, 50, and 83 h −1 ) and pH values (6.0, 7.0, and 8.0). The optimal k L a and pH were 38 h −1 and 7.0, respectively. Under these conditions, the maximal cell production obtained was 8.0 g/L, and the volumetric and specific lipase production reached high levels of activity, approximately 800 U/L and 150 U/g cell, respectively, after 12 h of cultivation. This result was approximately five times higher than that obtained in the shake flask cultures. The relationship between cell growth and lipase production was found to be associated with growth by the Luedeking-Piret model. © KSBB

Influence of Mass Transfer and Kinetics on Biodiesel Production Process

“…To remove the unwanted glycerol from the wanted biodiesel, glycerol may also be used as a substrate in an enzyme reaction. Volpato et al (2009) studied the effects of oxygen volumetric mass transfer coefficient and pH on lipase production by Staphylococcus warneri EX17. The principal objectives of this study were to evaluate the kinetics of lipase production by Staphylococcus warneri EX17 under different oxygen volumetric mass transfer coefficients (k L a) and pH conditions in submerged bioreactors, using glycerol (a biodiesel by-product) as a carbon source (Volpato et al, 2009).…”

“…Volpato et al (2009) studied the effects of oxygen volumetric mass transfer coefficient and pH on lipase production by Staphylococcus warneri EX17. The principal objectives of this study were to evaluate the kinetics of lipase production by Staphylococcus warneri EX17 under different oxygen volumetric mass transfer coefficients (k L a) and pH conditions in submerged bioreactors, using glycerol (a biodiesel by-product) as a carbon source (Volpato et al, 2009). To remove the unwanted glycerol from the wanted biodiesel, glycerol may also be used as a reactant in a chemical reaction for the production of dichloropropanol.…”

Optimization of lipase production by Staphylococcus warneri EX17 using the polydimethylsiloxanes artificial oxygen carriers

“…The bioreactor was equipped with temperature, agitation, aeration, and pH controllers and two Rushton turbines with six flat-blades. The culture medium used was optimized in a previous study [20], and contained (in g/l): peptone, 10; yeast extract, 5; raw glycerol from biodiesel synthesis, 30; olive oil, 6; soybean oil, 5. The raw glycerol was used as the sole carbon source for cell growth and its composition was (in a weight basis): 82.8% glycerol, 5.5% ashes, 5.9% NaCl, 11.2% moisture, 0.5% monoacylglycerols, and pH 4.84.…”

Culture Conditions and Investigation of Bioreactor Configurations for Lipase Production by Rhizopus oryzae

“…During the last months, several reports were published stressing the need of searching for operating conditions in bioreactors to produce lipolytic enzymes from yeasts [9,35], bacteria [10], and fungi [21], but maximum activities of 700 U/L, 400 U/L, and 500 U/L, respectively, were obtained via the p-nitrophenyl esters method. Therefore, the extremely high levels obtained in this work with the same enzyme determination method point out the suitability of the proposed strategy as well as the bioreactor configuration to be implemented at higher scale for the production of lipolytic enzymes.…”

“…However, a considerable amount of the research carried out to date has focused on small-scale procedures, while less information is available on the particular characteristics of lipolytic enzyme biosynthesis in bioreactors and the feasibility of diverse culture modes, such as batch, fed-batch, or continuous systems [6][7][8]. Over the last few months, research concerning lipase production by yeasts and fungi in bioreactors has been employed to obtain high levels of lipase production, thus demonstrating the interest that the scale-up of this kind of biological process is triggering nowadays and then encouraging further research in this field [9][10][11][12].…”