Many microorganisms are able to produce polyhydroxybutyrate as a storage material. This natural, biodegradable polyester can replace fossil polymers in some applications, but is not equivalent to them in all properties. Through strain engineering or synthesis of the chiral building blocks for chemical polymerisation, we are developing new PHB variants with tailored properties for broader applications. For a cost-effective production of these polymers, we use the possibility of accumulating the PHB in cells from highly diluted biogenic waste streams and feed these into a material use.

Microorganisms can be part of biohybrid materials. The properties of these materials can be specifically influenced by selecting and modifying the microorganisms used. At the Chair of Chemistry of Biogenic Resources, corresponding biohybrid materials are being investigated and their properties optimised. By using microbial biomass, the materials are sustainable. For example, cells from industrial fermentation processes can be used to create a higher-value utilisation option in addition to thermal/energetic utilisation. The cells can be considered as a platform for functionalisation of the material. The function of natural or recombinant proteins is preserved in the material and becomes macroscopically usable.

In the material use of petroleum, the production of materials or polymers takes up a large share. In the same way, the material use of biomass for the production of polymers offers great potential. In addition to biogenic polymers produced directly from microorganisms or plants, the production of monomers from biogenic raw materials with subsequent chemical polymerisation is an efficient way to obtain a real CO2 sink. It is important that not only so-called drop-in monomers are produced, which are supposed to replace the petroleum-based monomers 1:1. Ethylene for polyethylene from glucose makes no sense with a mass yield of only 30 % and would neither be economically viable nor would it really be ecological. Oxygenated monomers such as butanediol, succinic acid or furandicarboxylic acid have a better mass balance and can be produced more efficiently from biomass than from fossil raw materials. It is particularly interesting when the biogenic raw materials have properties that are not found in the molecules of fossil raw materials, i.e. when they have completely new polymer or material properties.

The following examples give an impression of our current activities in this field:

  • In our work on synthetic chemo-enzymatic reaction pathways, for example, we have developed new reaction routes to 1,4-butanediol, 2,3-butanediol, isobutanol or acetoin from sugars.
  • Based on waste streams from the pulp industry (terpenes), we have developed a new class of chiral polyamides that are superior to fossil polymers in properties such as hardness and transparency.
  • By optimising integrated whole-cell biotransformation processes, we have provided long-chain dicarboxylic acids for bio-based polyesters and polyamides.