(German title: Silage als Rohstoff für die chemische Industrie)

Grass is a globally widespread renewable raw material with high biomass yields. For industrial use, however, the problem of storing grass cuttings must be taken into account. Ensiling is a good way of making grass cuttings suitable for long-term storage. The lactic acid fermentation that takes place during this process leads to the preservation of the grass cuttings on the one hand and on the other hand already results in an initial increase in value, as lactic acid is one of the most important platform chemicals for plastics made from renewable raw materials.

In a joint project between the Department of Bioprocess Engineering and the Department of Thermal Process Engineering at the Technical University of Kaiserslautern and the Technical Biochemistry working group at Saarland University, the use of grass silage as a raw material for fermentative and chemical-catalytic processes for the production of basic and fine chemicals is to be developed. On the one hand, the extent to which silage can be fermented directly and, on the other hand, how fermentation characteristics can be improved by simple processing methods will be investigated. In a first process step, a pressed juice is obtained from the silage, from which a raw lactic acid fraction is obtained using extractive processes. Secondly, the hydrolysis of the polysaccharides contained in the silage is investigated. These raw fractions are then used in fermentative processes to produce solvents (ethanol, 1,2-propanediol) and basic chemicals (itaconic acid, succinic acid) or amino acids. The products produced are to be obtained as in-situ as possible using innovative processes. The silage should be used as completely as possible. This is why, for example, the raffinate from lactic acid extraction is used as a supplement in the fermentations. In addition, all residues are to be used for the production of biogas.