Processing Parameter Variation for PEF-Assisted Lipid Extraction from Oleagineous Yeasts

Some yeast strains can produce and store lipids. Compared to microalgae, oleaginous yeast can grow heterotrophically and space-saving in fermenters up to biomass densities of more than 40 gdw/L, which can save the preconcentration step usually required in microalgae processing. Furthermore, the fatty acid profile of lipids from oleagineous yeasts better matches the requirements for biofuel or bio-lubricant applications. One hurdle of PEF-processing of oleagineous yeasts is the comparably high conductivity of yeast suspensions of around 10 mS/cm.
In this contribution we will report about our studies on the effect of processing variations for PEF-assisted lipid extraction from Saitozyma podzolica, DSM 27192. Lipid yields for washed and unwashed biomass will be compared. Also, the influence of treatment field strength on product yield for the washed and un-washed biomass will be discussed. Electric field amplitude of the 1µs pulses was varied between 14 kV/cm and 40 kV/cm. As already known from studies on other biomass, this study confirms that the lipid yield depends on the administered specific treatment energy also for oleagineous yeasts. ... mehrElectric field amplitude plays a subordinate role.
Finally, a comparison of lipid yields for low-field-strength PEF-treatments of washed and un-washed yeast biomass will show, that including a washing step increases the lipid yield for comparable treatment energy expenditure.