Modeling of oleaginous fungal biofilm developed on semi-solid media

• Published in: Bioresource technology 2011-10, Vol.102 (20), p.9697-9704
• Main Authors: Economou, Ch.N., Vasiliadou, I.A., Aggelis, G., Pavlou, S., Vayenas, D.V.
• Format: Article
• Language: English
• Subjects: biodiesel; Biofilm; Biofilms; Biological and medical sciences; Biotechnology; Carbohydrate Metabolism; Diffusion; Fermentation; Fundamental and applied biological sciences. Psychology; Fungi; Kinetics; Lipid accumulation; Lipids; Mathematical models; Methods. Procedures. Technologies; Microbial engineering. Fermentation and microbial culture technology; Modeling; Models, Theoretical; Mortierella; Mortierella - metabolism; Mortierella isabellina; nitrogen; oleaginous fungi; Semi-solid processing; Semi-solid state fermentation; solid state fermentation; Sorghum; Sugars; sweet sorghum
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2011.08.003

► A biofilm model was developed to describe the accumulation of oil in semi-solid state fermentation. ► The model employed double-substrate limitation kinetics with sugar inhibition. ► This is the first study that describes the lipid accumulation process in fungal biofilm. ► The study establishes a new approach to fungal lipid accumulation. An oleaginous fungus, Mortierella isabellina, able to transform efficiently sugar to storage lipid, was used as a model microorganism which develops a biofilm structure during the semi-solid fermentation process for the production of biodiesel from sweet sorghum. A mathematical model was developed to describe the fungal oil production in M. isabellina biofilm. The model describes diffusion and consumption of sugars and nitrogen of sweet sorghum and single cell oil production in a biofilm, which grows according to the kinetics of double-substrate limitation (sugars and nitrogen) with sugar inhibition. Experimental data from a previous experimental study were used to determine the kinetic parameters of the model. Maximum biofilm thickness and the percentage of lipid inside the biofilm were estimated using the model at 1892μm and 15%, respectively. The proposed mathematical model could prove a useful tool for designing semi-solid fermentation processes.