Method for the production of carboxylic acids under unsterile conditions

A method for biotechnological production of carboxylic acids, wherein the method comprises:

• culturing of microorganisms under unsterile conditions in a culture medium containing waste water,
• wherein the waste water comprises carbon-rich compounds and/or the method comprises adding carbon-rich compounds to the waste water,
• wherein the unsterile conditions comprise that before, during and after cultivation, no chemical or thermal sterilization measures and pasteurization measures are applied,
• the microorganisms comprise the yeast strain Yarrowia lipolytica H181 (DSM 7806),
• the carboxylic acids to be produced comprise at least one substance selected from the group consisting of aconitic, malic, succinic, citric, fumaric, isocitric, α-ketoglutaric, oxaloacetic, pyruvic and itaconic acids, and
• the carbon-rich compounds comprise at least one substance selected from the group consisting of monoglycerides, diglycerides, triglycerides, fatty acids, fatty acid methyl or ethyl esters, ethanol, methanol, glycerol, glucose, fructose, galactose, lactose, lactic acid, saccharose, xylose, arabinose, and n-alkanes;
• and
• wherein the method comprises at least one pre-cultivation step for producing inoculum of the yeast Yarrowia lipolytica H181 (DSM 7806) in an unsterile manner.