Development of new biocatalysts for the production of long-chain dicarboxylic acids
Long-chain dicarboxylic acids can be used in many industrial applications as platform chemicals, for example in the polymer industry for the production of polyamides or polyesters. Dicarboxylic acids are mainly produced by chemical processes. In the chemical process, petrochemical raw materials are used for synthesis, and long-chain dicarboxylic acids (> 12 carbon atoms) are difficult to synthesize chemically.
Alternatively, certain yeast strains can be used for dicarboxylic acid production. These can convert alkanes or fatty acids into dicarboxylic acids with a corresponding chain length. The production of dicarboxylic acids in yeast takes place via the so-called omega-oxidation pathway, but at the same time the dicarboxylic acid formed is further metabolized in the beta-oxidation pathway of the yeast and used for energy production.
To prevent degradation of the dicarboxylic acids formed in the cell and to ensure complete conversion of fatty acids as renewable raw materials into dicarboxylic acids, strategies must be developed to block the beta-oxidation pathway in the cell. One possibility is the deactivation (knock-out) of genes of the beta-oxidation pathway using genetic engineering methods.
Such a modified yeast strain is already known from literature and achieves concentrations of over 100 g/l of long-chain dicarboxylic acids in fermentative processes (Picataggio et al., 1992, Metabolic engineering of Candida tropicalis for the production of long-chain dicarboxylic acids. Bio/Technology. 10: 894 - 898). Since this yeast strain is the yeast Candida cenakerosene, its use for the industrial production of long-chain dicarboxylic acids is limited.
Fraunhofer IGB is therefore working in the EU-funded BioConSepT project to provide new, microbiologically harmless production strains for dicarboxylic acid production.