The effect of sodium nitrite on the growth of Micrococcus denitrificans

✍ Scribed by Bovell, Carlton

• Publisher: Springer-Verlag
• Year: 1967
• Weight: 324 KB
• Volume: 59
• Category: Article
• ISSN: 0003-9276
• DOI: 10.1007/bf00406312

✦ Synopsis

Nitrite accumulates during the growth of M. denitri/icans in a medium in which nitrate is the terminal oxidant. If H~ is the electron donor for nitrate reduction, the level of nitrite produced is sufficiently high to inhibit hydrogenase; this inhibition consequently inhibits growth. Yeast extract alleviates the inhibition and permits a resumption of growth. The release from inhibition may result from the provision of a growth factor for, or from a more rapid induction of, a system for nitrite dissimilation.

In 1954, VV, R~OEV~, KOSTE~ and VA~ NI]~V~LT reported the isolation from garden soil of an autotrophic bacterium which used molecular hydrogen as the source of energy for the fixation of carbon dioxide, and nitrate as the terminal oxidant. This isolate proved to be identical to Micrococcus denitri/icans described by BEIJERINCK in 1910.

M. denitri/icans is a particulary interesting bacterium by virtue of its potential for growth under diverse cultural conditions. As an energy source for anaerobic growth, the bacterium may use hydrogen or organic compounds such as sucrose, glucose, succinate and glycerol. Under these conditions, denitrffication occurs: nitrate is reduced to gaseous nitrogen. Alternatively, oxygen may be the terminal electron acceptor; the organism can grow aerobically as a hydrogen autotroph or as a heterotroph with any of the aforementioned organic compounds. VE~O]~V]~, KosT~ and vA~ NI]~V~LT (1954) and KLcYvv,~ and Vv,~oEvwN (1954) state that trace quantities of yeast autolysate are required for growth with hydrogen and nitrate. This requirement for yeast autolysate is peculiar. Growth factors cannot be required for the metabolism of hydrogen or for the fixation of carbon dioxide, since under aerobic conditions the organism demonstrates no such requirement. Nor can growth factors be required for the nitrate-reducing system, since yeast autolysate is not a necessary supplement to the * Dedicated to Prof. C. B. VAN NI~,L on the occasion of his 70th birthday.