(608b) Production of Microbial Lipids From Sweet Potato Starch Using Lipomyces Starkeyi

Production of microbial lipids from sweet potato starch using Lipomyces starkeyi

Sharif Rahman, Ramalingam Subramaniam, Stephen Dufreche, Rakesh Bajpai, and Mark E. Zappi,

Bioprocessing Research Laboratory

Department of Chemical Engineering

University of Louisiana at Lafayette, Lafayette, LA

It is well known that medium costs contribute substantially to the overall cost of biological products. This is true for microbial lipids as well. Based on our extensive research with production of lipids from starch using Lipomyces starkeyi, an economic analysis of the production process was conducted. This analysis revealed that operating and separation costs are the two key cost contributing factors other than the carbon source. Experiments were conducted to minimize cost per gallon of lipids by accounting for all the cost contributing factors. Those factors included carbon source, C/N ratio, medium optimization, reactor operation, and selection of solvent selection for extraction of lipids from Lipomyces starkeyi. Experiments were conducted in shake flasks as well as in the fermenters by controlling the pH, temperature and aeration. Lipid content of 0.75 g lipid/g dry weight cells was obtained from the high density cultivations. Fatty acid profile was analyzed for all the cases. Process simulator Aspen plus was used to simulate, scale-up, and economic analysis of the project. The results will be discussed during the presentation.