Abstract
The R and M variants of a purple photosynthetic bacterium Rhodobacter sphaeroides 2R grown on a medium with acetate accumulate poly-ß-hydroxybutyrate (PHB). Accumulation of this polymer occurs in the cells grown either anaerobically on the light or aerobically in the dark. On the medium with C/N imbalance (C/N = 4), PHB content during the stationary growth phase under aerobic conditions in the dark was 40 and 70% of the dry biomass of the R and M variant, respectively. The Rba. sphaeroides M variant is therefore a promising culture for large-scale PHB production. Investigation of activity of the TCA cycle enzymes revealed that decreased activity of citrate synthase, the key enzyme for acetate involvement in the reactions of the tricarboxylic acid cycle, was primarily responsible for enhanced PHB synthesis by Rba. sphaeroides. Moreover, the Rba. sphaeroides M variant grown under aerobic conditions in the dark exhibited considerably lower activity of NADH oxidase, which participates in the oxidation of reduced NADH produced in the TCA cycle during acetate oxidation. The combination of these two factors increases the possibilities for acetate assimilation via an alternative mechanism of PHB synthesis.
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Brandl, H., Gross, R.A., Lenz, R.W., and Fuller, R.C., Plastics from bacteria and for bacteria: poly(betahydroxyalkanoates) as natural, biocompatible, and bio degradable polyesters, in Microbial Bioproducts. Advances in Biochemical Engineering/Biotechnology, Berlin Heidelberg: Springer, 1990, vol. 41, pp. 77–93.
Liebergesell, M., Hustede, E., Timm, A., Steinbüchel, A., Fuller, R.C., Lenz, R.W., and Schlegel, H.G., Formation of poly(3-hydroxyalkanoates) by phototrophic and chem olithotrophic bacteria, Arch. Microbiol., 1991, vol. 155, no. 5, pp. 415–421.
Kondratieva, E.N. and Krasilnikova, E.N., Phototropic bacteria as producers of polyßhydroxybuyrate, Microbiology (Moscow), 1989, vol. 70, no. 6, pp. 768–771.
Philip, S., Keshavarz, T., and Roy, I., Polyhydroxyal-kanoates: biodegradable polymers with a range of appli cations, J. Chem. Technol. Biotechnol., 2007, vol. 82, no. 3, pp. 233–247.
Brandl, H., Gross, R.A., Lenz, R.W., Lloyd, R., and Fuller, R.C., The accumulation of poly (3hydroxyal kanoates) in Rhodobacter sphaeroides, Arch. Microbiol., 1991, vol. 155, no. 4, pp. 337–340.
Khatipov, E., Miyake, M., Miyake, J., and Asada, Y., Accumulation of polyßhydroxybutyrate by Rhodobacter sphaeroides on various carbon and nitrogen sub strates, FEMS Microbiol. Lett., 1998, vol. 162, no. 1, pp. 39–45.
Sangkharak, K. and Prasertsan, P., Optimization of polyhydroxybutyrate production from a wild type and two mutant strains of Rhodobacter sphaeroides using statistical method, J. Biotechnol., 2007, vol. 132, no. 3, pp. 331–340.
Sangkharak, K. and Prasertsan, P., Nutrient optimiza tion for production of polyhydroxybutyrate from halo tolerant photosynthetic bacteria cultivated under aero bicdark condition, Electronic J. Biotechnol., 2008, vol. 11, no. 3.
Ivanovsky, R.N., Mil’ko, E.S., and Mil’ko, D.M., Isolation of the phase variants of the purple photosynthetic bacterium Rhodobacter sphaeroides and investigation of their molecular, physiological, biochemical, and mor phological characteristics, Microbiology (Moscow), 2013, vol. 82, no. 2, pp. 169–174.
Mil’ko, E.S., Krasil’nikova, E.N., Keppen, O.I., Lebedeva, N.V., and Ivanovsky, R.N., Metabolism of the phase variants of the phototrophic bacterium Rhodobacter sphaeroides, Microbiology (Moscow), 2014, vol. 83, no. 4, pp. 322–325.
Law, J.H. and Slepecky, R.A., Assay of polybetahydroxybutyric acid, J. Bacteriol., 1961, vol. 82, pp. 33–36.
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Original Russian Text © E.N. Krasil’nikova, E.S. Mil’ko, O.I. Keppen, N.V. Lebedeva, R.N. Ivanovskii, 2015, published in Mikrobiologiya, 2015, Vol. 84, No. 3, pp. 311–315.
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Krasil’nikova, E.N., Mil’ko, E.S., Keppen, O.I. et al. Poly-ß-hydroxybutyrate accumulation by Rhodobacter sphaeroides phase variants. Microbiology 84, 347–350 (2015). https://doi.org/10.1134/S002626171503011X
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DOI: https://doi.org/10.1134/S002626171503011X