The downstream processing of biomolecules from fermentation broth involves several unit operations such as cell disruption, centrifugation, dialysis, chromatography, etc. However liquid-liquid extraction (LLE) is a more favourable option since it combines the early processing steps into a single operation. LLE can be applied on a variety of bioprocess streams. For instance a biopharmaceutical stream that contains a therapeutic protein or a stream from microalgal cultivation to separate the protein from the lipid fraction of the biomass.
In order to make microalgae biofuel economically viable there is need to incorporate the biorefinery approach. The current method for extraction of lipids from algae uses organic solvent which causes denaturation of the protein. The use of chromatographic methods makes the process for purification of biopharmaceutical proteins expensive. Thus there is need to develop mild but efficient extraction method.
Aim and research question
The aim of the thesis is to develop an extraction process using polymers and magnetic ionic liquids for the separation of proteins from biopharmaceutical feed stream and proteins and lipids from algal feed streams.
A known mild liquid-liquid extraction method will be selected and studied to separate proteins (Rubisco) and lipids (carotenoids, phospholipids/galactolipids) in an algal feed stream and proteins (monoclonal antibodies and bovine serum albumin) in biopharmaceutical feed streams. These proteins and lipids would then be screened for suitable extraction conditions with magneto-responsive ionic liquids. The behaviour of the proteins in the system with respect to degradation and modification will also be monitored. Finally the system would be studied for an integrated recovery of proteins and lipids from microalgae. The studies will focus on extraction/solubilisation rates and stimuli responsive recovery.