A mathematical model for the study of lipid accumulation in oleaginous microorganisms. I. Lipid accumulation during growth of Mucor circinelloides CBS 172-27 on a vegetable oil

Abstract

   The accumulation of lipids In microorganisms cultivated In growth media having as sole carbon and energy source vegetable or animal fat has been an object of research and industrial interest for many years. Interestingly, the accumulated fat often has a composition and structure much different from that of the fat present In the substrate.
   The present work describes a mathematical approach to the accumulation of fat by oleaginous microorganisms growing on medium containing vegetable oil as carbon source. A mathematical model, correlating the accumulation of reserve fat with the growth of microbial population and the available quantity of exocellular fat, is proposed. This model is verified by experimental data taken by cultivation of Mucor circinelloides CBS 172-27 on sunflower oil.
   The proposed model is described by the equation: X_L = X_Lo + L_o(1-e^-k₂.t)– (lnx-lnx_o)/k₁    where X_L(mg/l) the concentration of reserve lipids at time t(h), X_Lo(mg/l) the concentration of lipid reserves at time t=o, L_o(mg/l) the initial concentration of exocellular fat (a t=o), X(mg/l) the concentration of fat-free biomass at a given time t and Xo the concentration of fat-free biomass at time t=o; k₁ and k₂ constants.