Fractionation of baker's yeast vinasse via ultrafiltration: assessment of feasibility

Summary The potential of vinasse, gained from baker′s yeast production for the recovery of valuable molecules (invertase, food grade proteins and betaine), has been assessed. Particularly natural betaine, a trimethyl derivative of glycine, attracts more and more attention in human and animal nutrition. In this work, a straightforward membrane‐based process for the recovery of natural betaine and a very promising betaine‐rich protein fraction from fermentation broth of baker′s yeast was developed. The difficult separation of external invertase from yeast cells was observed in this work. Anyway, a residual invertase activity was found in vinasse, but it could not be efficiently purified to generate an industrial‐strength product. The presented process can be easily implemented in a conventional baker's yeast production plant by integrating an ultrafiltration station and an adsorption system. Based on our calculations, a potential recovery up to 1486 t year −1 of betaine‐rich proteins (5 € kg −1 ) and 593 t year −1 Betafin ® similar natural betaine (6–7 € kg −1 ) may be achieved.