L-malic acid is a C4 dicarboxylic acid and a potential key building block for a bio-based economy. Malic acid is mainly used in the food and beverage industry, metal cleaning and pharmaceuticals, but can also serve as a polymerization initiator. A sustainable alternative to traditional petroleum-based synthesis is the microbial production of L-malic acid from renewable resources. The mold Aspergillus oryzae is known for its high production capacity for L-malic acid and has been granted GRAS status, making it a promising candidate for industrial fermentation.

Specifically, the project aims to bring the production of L-malic acid to pilot scale and optimize it. Sub-objectives of the project are therefore:

1. evaluation of the existing batch process with regard to its suitability for industrial scale and investigation of further cultivation options, such as fed-batch and repeated-batch.

2. identification and adjustment of process parameters, such as morphology, pH regulation and mixing, to enable scale-up.

3. stepwise process transfer to large scale from 2 L to 100 - 500 L.