No description available.

This study investigated the extraction of lipids and β-carotene from microalgae using microemulsions as an alternative to current solvents. Type I and type IV microemulsions composed of 4% lecithin, sorbitan monooleate, PEG-6-caprylic glycerides, and ethyl caprate were able extract lipids from lyophilized microalgae better than hexane and ethyl caprate. HPLC quantified the extracted β-carotene, with type IV microemulsions extracting the most β-carotene at 0.137±0.074% (w/w) of the total microalgae biomass after an hour. The growth recovery of the microalgae after extraction was observed over 2 weeks. Variability in the data prevented definite conclusions about the ability of algae to grow after extraction. The type IV extractions consistently showed some signs of survival. After two weeks, a pale-green colour was observed in the 15min and 1h extractions. This study showed that microemulsions can successfully extract lipids from microalgae; future work would apply microemulsion formulations to live algal cells for in-situ extraction.

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The technique of extraction with supercritical carbon dioxide (SC-CO$ sb2$), which is now used routinely for the recovery of non-polar analytes from a variety of liquid and semipermeable solid media, was extended to the efficient extraction of metal ions. Measurements of the solubilities in SC-CO$ sb2$ corroborated the hypothesis that the non-polar character of a series of tetraalkylammoniun dialkyldithiocarbamates ion pairs was influenced (i) primarily by the chain length of the alkyl substituent(s) on the carbamate nitrogen and (ii) to a lesser extent, by the chain length of the alkyl substituent(s) on the ammonium counter ion. In operation, analyte metal(s) in aqueous medium was derivatized by in situ complexation with the dithiocarbamate complexing reagent and the product complex(es) was partitioned into the SC-CO$ sb2$ mobile phase then purged from the extractor by replacing the headspace with fresh solvent. A novel silica flame-in-tube interface was developed for the sensitive detection, by atomic absorption spectrometry (AAS), of As, Cd, Cu, Mn, Pb, Se, or Zn in SC-CO$ sb2$ extractor eluate. For different analyte elements, the limits of detection (LODs) ranged from sub-nanogram to low picogram if standard was flow injected into the mobile phase. These sensitivities permitted differences in the rates of mobilization of different forms of the analyte metal from various media to be explored as a technique for probing the interaction of the analyte metal with the matrix. A portion of the Zn burden in fresh bovine liver was mobilized rapidly in the absence of complexing agent and the remainder was solubilized more rapidly than the Zn in a freeze-dried reference material of this tissue. The nebulizer assembly of a conventional flame-AAS was modified to extend the range of metals amenable to on-line detection. Supplemental heating of the inlet air to 200$ sp circ$C resulted in an on line detector which provided approximately a ten-fold improvement over convention

Pectin is a polysaccharide found in plant cell walls. It is a linear molecular chain of D-galacturonic acid units linked by a 1—»4 glycosidic bonds. Pectin is widely used in the food industry. The main sources of pectin are citrus fruits and apple. In South Africa, pectin is still imported whereas it can be produced from waste peels that result from citrus processing. A consortium was formed by CSIRBio/Chemtek, Chemin, Kat River Co-op and University of KwaZulu Natal (UKZN) to investigate pectin production. UKZN was to develop the drying (for off-season purposes) and extraction technology required for pectin production. The project was categorized into two phases; the drying and the extraction phases. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2009.

Phase equilibrium data is essential in the operation, design and development of industrial / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2008.

This study investigated the extraction of lipids and β-carotene from microalgae using microemulsions as an alternative to current solvents. Type I and type IV microemulsions composed of 4% lecithin, sorbitan monooleate, PEG-6-caprylic glycerides, and ethyl caprate were able extract lipids from lyophilized microalgae better than hexane and ethyl caprate. HPLC quantified the extracted β-carotene, with type IV microemulsions extracting the most β-carotene at 0.137±0.074% (w/w) of the total microalgae biomass after an hour. The growth recovery of the microalgae after extraction was observed over 2 weeks. Variability in the data prevented definite conclusions about the ability of algae to grow after extraction. The type IV extractions consistently showed some signs of survival. After two weeks, a pale-green colour was observed in the 15min and 1h extractions. This study showed that microemulsions can successfully extract lipids from microalgae; future work would apply microemulsion formulations to live algal cells for in-situ extraction.

No description available.