Polyphosphate formation by Acinetobacter johnsonii 210A : effect of cellular energy status and phosphate-specific transport system

• Published in: Applied microbiology and biotechnology Vol. 51; no. 5; pp. 639 - 646
• Main Authors: VAN NIEL, E. W. J, DE BEST, J. H, KETS, E. P. W, BONTING, C. F. C, KORTSTEE, G. J. J
• Format: Journal Article
• Language: English
• Published: Berlin Springer 31.05.1999; Springer Nature B.V
• Subjects: Acinetobacter johnsonii; Agrotechnological Research Institute; Bacteria; Biological and medical sciences; Biology of microorganisms of confirmed or potential industrial interest; Biomass; Biosynthesis; Biotechnology; E coli; Energy; Energy sources; Fundamental and applied biological sciences. Psychology; Instituut voor Agrotechnologisch Onderzoek; Kinases; Laboratorium voor Microbiologie; Lipids; Microbiological Laboratory; Microbiologie; Microbiology; Miscellaneous; Mission oriented research; Phosphates; Phosphates; Microorganism growth; Enzyme; Transferases; Biological transport; Neisseriaceae; Biosynthesis; Metabolism; Continuous process; Phosphate polymer; Microorganism culture; Bacteria; Micrococcales; Polyphosphate kinase
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s002530051444

In acetate-limited chemostat cultures of Acinetobacter johnsonii 210A at a dilution rate of 0.1h^sup -1^ the polyphosphate content of the cells increased from 13% to 24% of the biomass dry weight by glucose (100mM), which was only oxidized to gluconic acid. At this dilution rate, only about 17% of the energy from glucose oxidation was calculated to be used for polyphosphate synthesis, the remaining 83% being used for biomass formation. Suspensions of non-growing, phosphate-deficient cells had a six- to tenfold increased uptake rate of phosphate and accumulated polyphosphate aerobically up to 53% of the biomass dry weight when supplied with only orthophosphate and Mg^sup 2+^. The initial polyphosphate synthesis rate was 98±17nmol phosphate min^sup -1^mg protein^sup -1^. Intracellular poly-β-hydroxybutyrate and lipids served as energy sources for the active uptake of phosphate and its subsequent sequestration to polyphosphate. The H^sup +^-ATPase inhibitor N,N'-dicyclohexylcarbodiimide caused low ATP levels and a severe inhibition of polyphosphate formation, suggesting the involvement of polyphosphate kinase in polyphosphate synthesis. It is concluded that, in A. johnsonii 210A, (i) polyphosphate is accumulated as the energy supply is in excess of that required for biosynthesis, (ii) not only intracellular poly-β-hydroxybutyrate but also neutral lipids can serve as an energy source for polyphosphate-kinase-mediated polyphosphate formation, (iii) phosphate-deficient cells may accumulate as much polyphosphate as activated sludges and recombinants of Escherichia coli designed for polyphosphate accumulation.[PUBLICATION ABSTRACT]