A Method For The Extraction Of Liquid Hydrocarbons From microalgal Biomass

In early 1980's microalgae were proposed as a source of energy, chemicals, and pharmaceutical compounds (vitamins, fatty acids, etc.). This necessitated culture of microalgae in synthetic media or wastewater treatment ponds and the subsequent extraction of the compounds from the biomass. The present study 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 the necessary laboratory data regarding the fundamental process parameters. In this two-phase research project, a microalgal lipid extraction method was selected against the available methods for fat extraction from fatty tissue. Solvent extraction was selected as the method of choice. For this method, tight fundamental process parameters were identified which included pre-treatment, solvent type, mixing, temperature, concentration of microalgae, ratio of solvent to microalgae (S:A) (Volatile weight basis), time of extraction, and lastly the microalgal batch or type. In the first phase, two devised procedures were employed to determine the applicable limiting values of solvent to microalgae ratio, and those of time. Another objective was to obtain levels which extract lipids in reasonable variations from other levels. Ratios of 10:1, 25:I, and 50:1 met the criteria for S:A ratio whereas the selected time levels were 5, 10, 15, 20, 30, 60, 90, 120, 240, and 1440 minutes.