Whey Lactose as a Raw Material for Microbial Production of Biodegradable Polyesters

Whey, a by-product of diary and cheese industry, constitutes the watery portion after the separation of fat and caseins from whole milk. Cheese whey is a surplus material produced in volumes almost equal to the milk processed in cheese manufactories, therefore its disposal as a waste causes serious pollution problems in the surrounding environment where it´s discarded. This is due to its enormous biochemical oxygen demand that is mainly caused by its high lactose content; as a consequence a large amount of industrial capital is requested for whey disposal. During the last years, the amounts of whey increased to such an extent that they cannot be simply used as animal feed as the most common application. To overcome these problems a sustainable alternative is to upgrade whey and its derivates to a resource for many value added industrial products, making whey not only a waste but also a valuable resource. The article presents a future-oriented, alternative strategy to use surplus whey, namely its upgrading to the role of a raw material for cost-efficient production of polyhydroxyalkanoate (PHA) biopolyesters. PHAs are a group of bio-based, bio-compatible and compostable bio-plastics of increasing significance for numerous industrial applications. Data for PHA production from whey on different production scales and techniques by various microbial species are compared and embedded in the entire scientific field of biopolymers. The review shows how the smart solution of an industrial waste disposal problem can be combined with enhanced cost efficiency in production of “green plastics”.