Organic acids

Organic acids, which usually contain at least one carboxyl group, are highly versatile compounds with a wide range of applications for industries such as consumer goods, food and beverage, pharmaceuticals, and chemicals. They are produced either from petroleum-based feedstock through multi-step chemical synthesis or from renewable resources via microbial biosynthesis. The target compounds of INCOVER – Citric acid, Itaconic acid and α-Ketoglutaric acid – contain additional functional groups (e.g. hydroxy- or oxocarboyxlic acid) and have an outstanding potential for an effective biotechnological production by yeast based bioprocesses.

Citric acid, a 6-carbon tricarboxylic acid, is one of the world's most important bulk chemicals solely produced by biosynthesis. In the EU alone, the current citric acid consumption is 530,000 t/annum, annual import is about 200,000 t, and the demand is expected it increase by 5% every year. Citric acid is used in many industrial processes as a cleaner, decalcifier, colour-stabilizer, acidulant and flavour enhancer. Citric acid is accepted worldwide as GRAS (generally recognized as safe), and used as food additive in the EU as approved by the E numbers: E330 (citric acid), E331-E333 (citrates). 

Itaconic acid, an unsaturated 5-carbon dicarboxylic acid, is used exclusively for technical applications. Therefore, itaconic acid is a component of applications such as polyesters, plastics, resins, adhesives or coatings. It is exclusively manufactured microbially by cultivation of the fungus Aspergillus terreus. In a market with an annual growth of 8-10%, 15,000 t/annum is consumed in EU. 

α-ketoglutaric acid (KGA), a 5-carbon dicarboxylic acid which is currently traded as a fine and specialty chemical, a variety of applications include use as a building block for the synthesis of heterocycles and novel elastomers or as an additive in diet preparations and infusion solutions. At present, KGA is synthesized chemically using different routes.

There are different applications of organic acid production, as shown in figure 1.