Biosorption processes

Biosorption on immobilized algea

Macroalgea used as adsorption matrix

© Bunke

The research group 'biosorption' is focused on the treatment of contaminated waste-water as well as on the separation of valuable compounds out of liquids. A special task is the development of sorptive processes by utilizing biomass.


Research is including cultivation, characterization, and immobilization of biomass, respectively. Under current observationare distribution equilibria, kinetics, and the column dynamics of the adsorption processes.


Involved researchers:

Gerald Bunke


Cooperations:

Helmholtz Zentrum Berlin für Materialien und Energiespeichering Bessy II

Bioprocess design for lipopeptide and polyketide production with Bacillus subtilis

Laboratory scale process of in situ lipopetide process removal

© Glazyrina

Various endophyte strains are an important potential source of antimicrobial substances.  Utilization of these bacteria as a biological agent for protection of plants is an alternative to chemical methods. Plant growth-promoting rhizobacteria, most of which are Pseudomonas and Bacillus, are applied to a wide range of agricultural species to enhance growth, for example, by promoting seedling emergence, plant biomass and disease control. One of the most commonly used organisms, the rhizobacterium B. subtilis, has an average of 4-5% of its genome devoted to antibiotic synthesis and has the potential to produce more than two dozen structurally diverse antimicrobial compounds. Among these antimicrobial compounds, lipopeptide antibiotics, which include surfactin, fengycin and iturin families, have broad spectrum of antifungal activities and polyketide antibiotics (difficidin, bacillaene) exhibiting strong antibacterial activity. These antibiotics have great potential as food preservatives and as plant protection agents against plant diseases.
Moreover lipopepptides have well-recognized potential uses in biotechnology and biopharmaceutical applications because of their surfactant properties. Naturally occurring surface-active compounds are attracting attention in recent years because they offer several advantages over chemical surfactants, such as low toxicity, inherent good biodegradability and ecological acceptability.

Even though interest in biosurfactants and plant protection biological agent is increasing, these compounds do not compete economically with chemical synthesized substances. The main reasons for this are a relatively low yield of these compounds and expensive and complex purification and separation methods.

The key milestones are medium optimization, optimization of environmental conditions such as pH, temperature, agitation, oxygen availability and investigation the influence of the oxygen limitation on the synthesis of lipopeptide and polyketide antibiotics. The other field of this project is downstream processing. In the scope of this project two different new ISPR-techniques were developed. The one method is a foam fractionation. The speciality of this new system is the combination of the foam fractionation with the adsorption-desorption process on polystyrene resins, which is more efficient than other commonly used ISPR-techniques. Another new ISPR-approach is based on removal and separation of biosurfactants from the culture broth by compressing and harvesting of the liquid surface layer using a new device called “Flounder”. This in situ removal strategy allows for stable and efficient fermentation process under intensive foaming conditions without the need to add any anti-foam agents.


Involved researchers:

Julia Glazyrina, Peter Neubauer

In situ removal and purification of biosurfactants by automated surface enrichment

Flounder in the adsorption (left) and harvesting state (right)

© Glazyrina

Biosurfactants are removed and separated from complex mixtures by compressing and harvesting the liquid surface layer during several extraction cycles. The automated collection pre-treatment in a custom-built glass body called ‘flounder’ is characterized.

This method is applied to Bacillus subtilis cultures, in which the lipopeptide antibiotic fengycin as well as the polyketide antibiotic bacillaene are removed from the cell suspension and separated from each other. The method is also compared to conventional methods that are used for biosurfactant separation and thereby evaluated.


Involved researchers:

Stefan Junne, Julia Glazyrina


Cooperation partner:

Dr. Klaus Lunkenheimer, Max-Planck-Institute of Colloids and Interfaces, Potsdam-Golm, Germany


Publication:
Glazyrina J., Junne S., Thiessen P., Lunkenheimer K., Götz P. In situ removal and purification of biosurfactants by automated surface enrichment. Applied Microbiology and Biotechnology. 2008 81(1) 23-31