BioConSepT - From the plant to the plastic

Biobased polymers from second-generation renewable resources

The raw materials for industrial biotechnology come primarily from agricultural products - glucose from sugar-containing plants such as sugar beet or starch-containing plants such as cereals, vegetable oils from seeds. However, these so-called first-generation bio-based raw materials are in competition with food production and their use for the production of biofuels or bio-based chemicals is controversial. One concept that is already being implemented in a biorefinery is the complete energetic and material use of bio-based raw materials of the so-called second generation. These include lignocellulose from wood waste or vegetable oils that are not used in the food industry.

The EU-funded BioConSepT project, which involves 30 European partners from research and industry in addition to the Fraunhofer IGB, is investigating the use of second-generation raw materials for the production of biobased polymers. The aim of the project is to provide processes that convert second-generation raw materials into valuable chemicals. These processes are up to 30 percent cheaper and more sustainable than corresponding chemical or biotechnological processes that use first-generation raw materials.

The partners have selected processes for producing chemicals from second-generation raw materials in which enzymatic, microbial and chemical reactions are used and combined. In a first selection process, 2,5-furan dicarboxylic acid, itaconic acid, succinic acid, long-chain dicarboxylic acids, diamines, diamides and epoxides were identified as target molecules. Furthermore, the production of biosurfactants and glycerol carbonate is considered. Breakthroughs in cost reduction and sustainability of the selected processes are to be achieved by introducing continuous processes, new reactors and selective separation technologies. Another goal of the project is to provide sample quantities for market testing of bio-based polymers, resins, plasticizers, biosurfactants and solvents.

Dicarboxylic acids from vegetable oils

Long-chain dicarboxylic acids are chemically complex and expensive to synthesize, but represent an interesting intermediate for the synthesis of plastics such as polyesters. Yeasts of the genus Candida or Pichia are able to oxidize fatty acids to the corresponding dicarboxylic acids. Fraunhofer IGB has already established a process for the production of dicarboxylic acids using the yeast Candida cenakerosene. Up to 100 g/l 1,18-octadecenedicarboxylic acid could be produced from oleic acid by fermentation in an optimized process [1]. In the course of the BioConSepT project, the formation of dicarboxylic acids from other fatty acids of vegetable oils is being investigated at Fraunhofer IGB. In addition to process development, new yeast strains for dicarboxylic acid production are currently being investigated and robust production strains are being generated which allow the highest possible dicarboxylic acid yield.

Epoxides from vegetable oils

The epoxidation of unsaturated fatty acids and triglycerides results in products with increased polarity and reactivity. These epoxides can be used as PVC stabilizers, plasticizers or in bio-based polymers. Epoxidized soybean oil (ESBO) is usually used as a stabilizer or plasticizer in various plastics such as polyvinyl chloride (PVC) or polylactic acid (PLA) [2, 3]. In addition, the use of vegetable oil epoxides for photoinitiated cationic polymerization in thin-film applications has been described in the plastics industry [4]. Within BioConSepT at Fraunhofer IGB a process for the enzymatic production of epoxides with an immobilized enzyme is used for the conversion of second generation vegetable oils, including vegetable oils from waste streams.

Closing the gap between laboratory and industrial practice

In 2014, BioConSepT will select the two most promising production processes in order to provide product quantities in the range of 100 kg to 1000 kg. The implementation of the selected processes from laboratory to industrial scale will take place in Fraunhofer CBP's multifunctional plant in Leuna. In this way, BioConSepT should help to further reduce the gap between laboratory and industrial practice for the production of chemicals from existing biomass.