Production of poly(3-hydroxybutyrate) from whey by cell recycle fed-batch culture of recombinant Escherichia coli

A new fermentation strategy using cell recycle membrane system was develope d for the efficient production of poly(3-hydroxybutyrate) (PHB) from whey b y recombinant Escherichia coli strain CGSC 4401 harboring the Alcaligenes l atus polyhydroxyalkanoate (PHA) biosynthesis genes. By cell recycle, fed-ba tch cultivation employing an external membrane module, the working volume o f fermentation could be constantly maintained at 2.3 l. The final cell conc entration, PHB concentration and PHB content of 194 g l(-1), 168 g l(-1) an d 87%, respectively, were obtained in 36.5 h by the pH-stat cell recycle fe d-batch culture using whey solution concentrated to contain 280 g lactose l (-1) as a feeding solution, resulting in a high productivity of 4.6 g PHB l (-1) h(-1).