title: Production of poly-beta-hydroxybutyric acid by microorganisms accumulated from river water using a two-stage perfusion culture system.
abstract: The perfusion culture system using a shaken ceramic membrane flask (SCMF) was employed to accumulate microorganisms separated from river water and to produce poly-beta-hydroxybutyric acid (PHB). Using a two-step culture method with a single SCMF, river microorganisms were cultured by separately feeding four representative carbon sources, n-propanol, lactic acid, methanol, and formic acid. After 140 h culture, the cell concentration and PHB content respectively reached 43 g/l and 35% when a propanol medium was fed. Using a two-stage perfusion culture with twin SCMFs, the seed cell mass was increased in the first SCMF and then supplied to the second flask for PHB production. As a consequence, the cellular PHB content rose to 51% in the second SCMF, while the cell concentration gradually increased to 25 g/l after 175 h perfusion culture. These results demonstrated the utility of the two-stage perfusion culture system for developing a cheap means of producing PHB coincident with wastewater treatment.
authors.affiliation: Department of Biological Science and Technology, Science University of Tokyo, 2641 Yamazaki, Noda, Chiba 278-8510, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Morimoto
authors.forename: F
authors.initials: F
authors.lastname: Tashiro
authors.forename: H
authors.initials: H
authors.lastname: Nagashima
authors.forename: K
authors.initials: K
authors.lastname: Nishizawa
authors.forename: F
authors.initials: F
authors.lastname: Nagata
authors.forename: Y
authors.initials: Y
authors.lastname: Yokogawa
authors.forename: T
authors.initials: T
authors.lastname: Suzuki