Fundamental parameters in extraction of lipids from wastewater-grown microalgal biomass

The work in this dissertation was initiated in response to the increasing need for experimental data regarding microalgal lipid extraction processes. A large-scale process could not be developed without prior laboratory data regarding the fundamental process parameters. To obtain this data required the following steps: (1) Selection and design of a quick and simple laboratory procedure for the extraction of microalgal lipids to provide a basis for the scale-up operation. (2) Identification of the fundamental process parameters that influence the extraction of lipids from microalgae. (3) Selection of different levels for these parameters and their respective values. (4) Examination of the effects of these factors on the extraction process. (5) Development of the final technique resulting from these studies.;In the studies, maximum percent lipids extracted by the devised procedure was 17.3% of the biomass volatile weight. An acidic soxhlet extraction method, released almost 25% of the biomass volatile weight as lipids.;Residual oil, CC, was defined as the amount of oil remained in the lipid-free (inert) volatile weight of biomass after each extraction period. This parameter was calculated from the measured values of extracted lipids and is important in the design of the extracting vessels. It was revealed that four factors; solvent type, pretreatment, concentration of microalgae, and solvent to microalgae ratio, influence the residual oil values at all the ten extraction time levels selected, between 5 and 1440 minutes.;The reduction in residual oil versus time of extraction was approximated by a polynomial exponential function with cubic terms. One general model seemed to explain the behavior of the data for each experiment.;The minimum residual oil was obtained when: chloroform-methanol 2:1 was used as the solvent, the microalgal cells were mechanically disrupted to release the tightly bound lipids and then freeze-dried, 50 mls of solvent was used per gram volatile weight of biomass, temperature was 25...