Cell disruption and processing of intracellular metabolites

Algae, bacteria and yeast contain a vast repository of biochemicals with high economic value. However, recovering these biochemicals involves expensive downstream processing (DSP) with only the most valuable materials or those giving high yields being currently recovered in biorefineries.

Our approach integrates cell disruption with controlled and continuous separation of biochemicals using high-pressure extraction and membrane separation technologies. Reduction of necessary processing steps, resource use (e.g water and energy), and environmental impact (e.g. wastewater) are our main goals.

Cell disruption using pressure change technology

The main emphasis of our work is on the development of pressure change technology (PCT) for microbial cell disruption. In the pressure change technology (PCT), a suspension is mixed with an inert gas under pressure at low temperatures (5 to 40°C). When the gas is suddenly relaxed, microbial cells are destroyed, their ingredients however are not changed. Pressure change technology is therefore especially suited to recover temperature- and oxygen-sensitive intracellular metabolites (e.g. polyunsaturated fatty acids, PUFA).

We have been able to demonstrate the disruption of microalgae cells using PCT in order to extract superior-quality components for food supplements or cosmetics, e.g. omega-3 fatty acids.

High-pressure extraction

A further focus of our work is to combine the PCT process with high-pressure extraction and fractionation methods. This way, high-value metabolites like omega-3 fatty acids can be extracted with greater energy efficiency than previously.

Advantages

The advantage of high-pressure extraction compared with conventional extraction methods is that no solvent is required, thus pollution due to solvents and chemicals is avoided or reduced. This in turn facilitates the treatment and the reutilization of the process water.

Selective separation using electro-membrane filtration

Released proteins, peptides and also other charged biomolecules can be separated or enriched selectively by means of electro-membrane filtration, as the molecules can be concentrated in just one process step and separated on the basis of functional fractions.

Electro-membrane filtration combines mechanical pressure filtration across a porous membrane with the motion of ions and molecules in an electric field. Thus the separation is not carried out only on the basis of their size, but at the same time also according to the charge. Compared with classical ultrafiltration this increases the yield and reduces the amount of work and expenditure for cleaning the plants.

Applications

  • Extraction of functional substances (e.g. fatty acids, essential oils)
  • Selective enrichment of proteins and peptides for food supplement
  • Removal of unwanted biomolecules

Reference project

Whey2Food – Enhanced protein fractionation from protein sources for their use in special food applications

Project duration: November 2013 – October 2015

By refining an electro-membrane process initially investigated at the University of Hohenheim, the Whey2Food project consortium is investigating how to obtain high-quality whey proteins fractions. 

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