Abstract
The mat-building cyanobacterium Microcoleus chthonoplastes carried out a mixed-acid fermentation when incubated under anoxic conditions in the dark. Endogenous storage carbohydrate was fermented to acetate, ethanol, formate, lactate, H(inf2), and CO(inf2). Cells with a low glycogen content (about 0.3 (mu)mol of glucose per mg of protein) produced acetate and ethanol in equimolar amounts. In addition to glycogen, part of the osmoprotectant, glucosyl-glycerol, was degraded. The glucose component of glucosyl-glycerol was fermented, whereas glycerol was released into the medium. Cells with a high content of glycogen (about 2 (mu)mol of glucose per mg of protein) did not utilize glucosyl-glycerol. These cells produced more acetate than ethanol. M. chthonoplastes was also capable of using elemental sulfur as the electron acceptor during fermentation, resulting in the production of sulfide. With sulfur present, acetate production increased whereas ethanol production decreased. Also, less formate was produced and the evolution of hydrogen ceased completely. In general, the carbon recoveries were satisfactory but the oxidation-reduction balances were too high. The latter could be explained by assuming the reduction of ferric iron, which is associated with the cells, mediated by the oxidation of formate. The switch from photoautotrophic to fermentative metabolism did not require de novo protein synthesis, and fermentation started immediately upon transfer to dark anoxic conditions. From the molar ratios of the fermentation products and from measurement of enzyme activities in cell extracts, we concluded that glucose derived from glycogen and glucosyl-glycerol is degraded via the Embden-Meyerhof-Parnas pathway.
Full Text
The Full Text of this article is available as a PDF (247.1 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Bateson M. M., Ward D. M. Photoexcretion and fate of glycolate in a hot spring cyanobacterial mat. Appl Environ Microbiol. 1988 Jul;54(7):1738–1743. doi: 10.1128/aem.54.7.1738-1743.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bradford M. M. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem. 1976 May 7;72:248–254. doi: 10.1006/abio.1976.9999. [DOI] [PubMed] [Google Scholar]
- Fothergill-Gilmore L. A., Michels P. A. Evolution of glycolysis. Prog Biophys Mol Biol. 1993;59(2):105–235. doi: 10.1016/0079-6107(93)90001-z. [DOI] [PubMed] [Google Scholar]
- Fox D. K., Roseman S. Isolation and characterization of homogeneous acetate kinase from Salmonella typhimurium and Escherichia coli. J Biol Chem. 1986 Oct 15;261(29):13487–13497. [PubMed] [Google Scholar]
- Garvie E. I. Bacterial lactate dehydrogenases. Microbiol Rev. 1980 Mar;44(1):106–139. doi: 10.1128/mr.44.1.106-139.1980. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ljungdahl L. G. The autotrophic pathway of acetate synthesis in acetogenic bacteria. Annu Rev Microbiol. 1986;40:415–450. doi: 10.1146/annurev.mi.40.100186.002215. [DOI] [PubMed] [Google Scholar]
- Neuer G., Bothe H. The pyruvate: ferredoxin oxidoreductase in heterocysts of the cyanobacterium Anabaena cylindrica. Biochim Biophys Acta. 1982 Jun 16;716(3):358–365. doi: 10.1016/0304-4165(82)90028-9. [DOI] [PubMed] [Google Scholar]
- Richardson L. L., Castenholz R. W. Enhanced Survival of the Cyanobacterium Oscillatoria terebriformis in Darkness under Anaerobic Conditions. Appl Environ Microbiol. 1987 Sep;53(9):2151–2158. doi: 10.1128/aem.53.9.2151-2158.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sanchez J. J., Palleroni N. J., Doudoroff M. Lactate dehydrogenases in cyanobacteria. Arch Microbiol. 1975 Jun 20;104(1):57–65. doi: 10.1007/BF00447300. [DOI] [PubMed] [Google Scholar]
- Smith A. J. Modes of cyanobacterial carbon metabolism. Ann Microbiol (Paris) 1983 Jul-Aug;134B(1):93–113. doi: 10.1016/s0769-2609(83)80099-4. [DOI] [PubMed] [Google Scholar]
- TRUEPER H. G., SCHLEGEL H. G. SULPHUR METABOLISM IN THIORHODACEAE. I. QUANTITATIVE MEASUREMENTS ON GROWING CELLS OF CHROMATIUM OKENII. Antonie Van Leeuwenhoek. 1964;30:225–238. doi: 10.1007/BF02046728. [DOI] [PubMed] [Google Scholar]
- Van Dijken J. P., Quayle J. R. Fructose metabolism in four Pseudomonas species. Arch Microbiol. 1977 Sep 28;114(3):281–286. doi: 10.1007/BF00446874. [DOI] [PubMed] [Google Scholar]
- Visscher P. T., van Gemerden H. Production and consumption of dimethylsulfoniopropionate in marine microbial mats. Appl Environ Microbiol. 1991 Nov;57(11):3237–3242. doi: 10.1128/aem.57.11.3237-3242.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]