Production of poly-3-hydroxybutyrate from lactose and whey by Methylobacterium sp. ZP24.

Methylobacterium sp. ZP24, isolated from a local pond, is able to grow in a medium containing 12 g l-1 lactose as a sole source of carbon, giving 5.25 g l-1 biomass yield and poly-3-hydroxybutyrate (PHB) up to 59% of its dry weight in 40 h. The isolate was also able to utilize cheese whey and produce 1.1 g l-1 PHB. Addition of ammonium sulphate increased the production of PHB from whey 2.5-fold. The potential of Methylobacterium sp. ZP24 in PHB production from cheese whey is discussed.