per glucose metabolized which is almost ten times as much as in O. limnetica. Moreover,
O. limnetica produced concomitantly sulfide and lactate, which we did not observe in our
strain.
As in O. limnetica, Oscillatoria sp. strain 23 and M. chthonoplastes, seem to possess the
enzymes for anaerobic dark metabolism constitutively. Product formation was linear for
about 12 hours and started without a lag period, immediately after the cultures were
transferred into dark anaerobic conditions.
We conclude that sulfur reduction and lactate fermentation may occur in many, if not all,
cyanobacteria that are frequently exposed to anaerobic conditions in the dark. The
importance of this phenomenon in natural environments as well as the elucidation of the
physiology of this process are currently under investigation.
COHEN Y., JORGENSEN B.B, PADAN E., SHILO M., 1975a. Sulphide-dependent anoxygenic photosynthesis in the
cyanobacterium Oscillatoria Limnetica. Nature (London) 257: 489 -492.
COHEN Y., PADAN E., SHILO M., 1975b. Facultative anoxygenic photosynthesis in the cyanobacterium Oscillatoria limnetica. Journal of Bacteriology 123: 855 -861.
COHEN Y., CASTENHOLZ R. W., HALVORSON H.O., 1984. Microbial mats: Stromatolites. Alan R. Liss, Inc., New
York, 498 pp.
GARLICK S., OREN, A., PADAN E., 1977. Occurrence of facultative anoxygenic photosynthesis among filamentous and unicellular cyanobacteria. Journal of Bacteriology 129: 623 - 629.
VAN GEMERDEN H., 1968. On the ATP generation by Chromatium in darkness. Archiv fur Mikrobiologie 64:
118-124.
GIBBS M., 1962. Fermentation. In: R.A. Lewin, Physiology and Biochemistry of Algae. Academic Press, New
York, San Francisco, London.: 91 - 97.
JORGENSEN B.B., REVSBECH N.P., BLACKBURN T.H., COHEN Y., 1979. Diurnal cycle of oxygen and sulfide
microgradients and microbial photosynthesis in a cyanobacterial mat sediment. Applied and Environmental
Microbiology 38:46-58.
JORGENSEN B.B., REVSBECH N.P., COHEN Y., 1983. Photosynthesis and structure of benthic microbial mats:
Microelectrode and SEM studies of four cyanobacterial communities. Limnology and Oceanography 28:1075
-1093.
KRUMBEIN W.E., BUCHHOLZ H., FRANKE P., GIANI D., GIELE C. WONNEBERGER K., 1979. O 2 and H 2 S
coexistence in stromatolites. A model for the origin of mineralogical lamination in stromatolites and banded
iron formations. Die Naturwissenschaflen 66: 381-389.
MCKINNEY G., 1941. Absorption of light by chlorophyll solutions. Journal of Biological Chemistry 140: 315
-322.
NOLL F., 1974. L-Lactat, Bestimmung mit LDH, GTP und NAD. In: H.U. Bergmeyer (ed.) Methoden der
Enzymatischen Analyse. Verlag Chemie, Weinheim, 3. Auflage Vol II : 1521 - 1525.
OREN A., SHILO M., 1979. Anaerobic heterotrophic dark metabolism in the cyanobacterium Oscillatoria
limnetica: sulfur respiration and lactate fermentation. Archives of Microbiology 122: 77 - 84.
OTTO R., 1981. An ecological study of starter streptococci. phD-thesis University of Groningen, Netherlands.
PFENNIG N., BIEBL H., 1976. Desulfuromonas acetoxidans gen. nov. and sp. nov., a new anaerobic, sulfurreducing, acetate oxidizing bacterium. Archives of Microbiology 110: 3-12.
PFENNIG N., BIEBL H., 1981. The dissimilatory sulfur-reducing bacteria. In: Starr, M.P. et al (eds.) The
Prokaryotes. Springer-Verlag, Berlin, Heidelberg, New York. 941 - 947.
REVSBECH N.P., JORGENSEN B.B., BLACKBURN T.H.; COHEN Y., 1983. Microelectrode studies of the photosynthesis and O 2 , H 2 S and pH profiles of a microbial mat. Limnology and Oceanography 28: 1062 - 1074.
308
O. limnetica produced concomitantly sulfide and lactate, which we did not observe in our
strain.
As in O. limnetica, Oscillatoria sp. strain 23 and M. chthonoplastes, seem to possess the
enzymes for anaerobic dark metabolism constitutively. Product formation was linear for
about 12 hours and started without a lag period, immediately after the cultures were
transferred into dark anaerobic conditions.
We conclude that sulfur reduction and lactate fermentation may occur in many, if not all,
cyanobacteria that are frequently exposed to anaerobic conditions in the dark. The
importance of this phenomenon in natural environments as well as the elucidation of the
physiology of this process are currently under investigation.
COHEN Y., JORGENSEN B.B, PADAN E., SHILO M., 1975a. Sulphide-dependent anoxygenic photosynthesis in the
cyanobacterium Oscillatoria Limnetica. Nature (London) 257: 489 -492.
COHEN Y., PADAN E., SHILO M., 1975b. Facultative anoxygenic photosynthesis in the cyanobacterium Oscillatoria limnetica. Journal of Bacteriology 123: 855 -861.
COHEN Y., CASTENHOLZ R. W., HALVORSON H.O., 1984. Microbial mats: Stromatolites. Alan R. Liss, Inc., New
York, 498 pp.
GARLICK S., OREN, A., PADAN E., 1977. Occurrence of facultative anoxygenic photosynthesis among filamentous and unicellular cyanobacteria. Journal of Bacteriology 129: 623 - 629.
VAN GEMERDEN H., 1968. On the ATP generation by Chromatium in darkness. Archiv fur Mikrobiologie 64:
118-124.
GIBBS M., 1962. Fermentation. In: R.A. Lewin, Physiology and Biochemistry of Algae. Academic Press, New
York, San Francisco, London.: 91 - 97.
JORGENSEN B.B., REVSBECH N.P., BLACKBURN T.H., COHEN Y., 1979. Diurnal cycle of oxygen and sulfide
microgradients and microbial photosynthesis in a cyanobacterial mat sediment. Applied and Environmental
Microbiology 38:46-58.
JORGENSEN B.B., REVSBECH N.P., COHEN Y., 1983. Photosynthesis and structure of benthic microbial mats:
Microelectrode and SEM studies of four cyanobacterial communities. Limnology and Oceanography 28:1075
-1093.
KRUMBEIN W.E., BUCHHOLZ H., FRANKE P., GIANI D., GIELE C. WONNEBERGER K., 1979. O 2 and H 2 S
coexistence in stromatolites. A model for the origin of mineralogical lamination in stromatolites and banded
iron formations. Die Naturwissenschaflen 66: 381-389.
MCKINNEY G., 1941. Absorption of light by chlorophyll solutions. Journal of Biological Chemistry 140: 315
-322.
NOLL F., 1974. L-Lactat, Bestimmung mit LDH, GTP und NAD. In: H.U. Bergmeyer (ed.) Methoden der
Enzymatischen Analyse. Verlag Chemie, Weinheim, 3. Auflage Vol II : 1521 - 1525.
OREN A., SHILO M., 1979. Anaerobic heterotrophic dark metabolism in the cyanobacterium Oscillatoria
limnetica: sulfur respiration and lactate fermentation. Archives of Microbiology 122: 77 - 84.
OTTO R., 1981. An ecological study of starter streptococci. phD-thesis University of Groningen, Netherlands.
PFENNIG N., BIEBL H., 1976. Desulfuromonas acetoxidans gen. nov. and sp. nov., a new anaerobic, sulfurreducing, acetate oxidizing bacterium. Archives of Microbiology 110: 3-12.
PFENNIG N., BIEBL H., 1981. The dissimilatory sulfur-reducing bacteria. In: Starr, M.P. et al (eds.) The
Prokaryotes. Springer-Verlag, Berlin, Heidelberg, New York. 941 - 947.
REVSBECH N.P., JORGENSEN B.B., BLACKBURN T.H.; COHEN Y., 1983. Microelectrode studies of the photosynthesis and O 2 , H 2 S and pH profiles of a microbial mat. Limnology and Oceanography 28: 1062 - 1074.
308