Supplementation of vitamin B2 (ribofavin) in poultry feeding is essential. For economic and environmental reasons, ribofavin is now produced biotechnologically, which, in most industrial production, is based on genetically modifed organisms (GMOs). Due to legislation, organic animals must be fed with GMO-free feeds, which also applies to the production processes of vitamin additives in the feed. Therefore, the main objective of experiments in this paper is the screening of GMOfree wild-type yeast strains overproducing ribofavin as a starting point to develop GMO-free ribofavin production lines that ensure the continuous supply of ribofavin for organic livestock. A screening of wild-type, non-GMO microorganisms overproducing ribofavin was conducted. The wild-type yeast Meyerozyma guilliermondii DSM 11947 produced the highest ribofavin concentration in the screening procedure. In order to provide a feasible and afordable certifed organic animal vitamin B2 supplement, the possibility of minimizing the expensive media component, yeast extract, was shown. This work shows the possibility of using a wild-type strain to achieve higher levels of ribofavin by means of bioprocess engineering and without metabolic engineering. A fermentation strategy at the laboratory scale is provided, where a yield of 30 mg ribofavin per g dry matter of yeast cells was achieved.

Anja Kuenz · Marius Tölle · Sarah Bromann
Tecniche produttive