(242c) Application of High Voltage for the Destabilization of Water-in-Oil Emulsion for the Extraction of Lipids From Microorganisms without Removal of Water

The conventional biofuel production process from microbial sources involves lipid extraction, fuel conversion (i.e. transesterification, catalytic cracking) and downstream processing. Other processes combine the first two steps into a single step (i.e. in situ transesterification, fluidized-bed catalytic cracking) to improve the process economics. However, all these processes are sensitive to water, which for microbial lipid sources constitutes up to 98% (weight) of the growth medium. Removal of water has proved to be the bottleneck for biofuel production from microbial sources (>50% of the biodiesel cost from activated sludge). Thus an alternative extraction strategy is needed. In this study, ternary systems containing alkane + lipids + water were established to design a water tolerant extraction scheme. Initial results indicated that for these ternary systems, emulsions could be formed in different regions of the phase diagram. These emulsions might complicate the phase separation. Thus, an electrostatic coalescence process was sought to break these emulsions. This process, which is important in the petroleum industry for removal of water from crude oil, involve application of electric field (~13-20 kV) to break emulsion drops and could be used to separate lipids in microbial consortia in the presence of water.