Fermentative production of 2,3-butanediol from cheese whey by a non-engineered mutant strain of Lactococcus lactis

Cheese manufacturing generates huge amounts of whey, part of it being disposed of as waste, posing serious environmental problems. However, whey is a valuable resource that can be valorized in a cost-effective and sustainable way, being fermentation processes a suitable option. The non-engineered mutant strain Lactococcus lactis 43103, a non-pathogenic microorganism, was found to efficiently produce 2,3-butanediol (2,3-BDO) from lactose. Culture of this strain in a whey-based medium adapted to its nutritional requirements under optimized fermentation conditions resulted in 2,3-BDO productions close to 18 g/L, representing 76.8 % of the maximum theoretical yield, which reached 94.7 % when acetoin, its immediate precursor in the metabolic pathway, was included. The fermentation performance was not very far from that of the best producers (natural or engineered) and was the best one among the non-pathogenic and non-engineered bacteria. These results open up the possibility of valorizing whey through fermentation to 2,3-BDO, a valuable platform chemical.