Influence of total and oxygen partial pressure on growth and metabolism of Methylomonas clara.

The effect of total and oxygen partial pressure on metabolic activities of Methylomonas clara has been investigated in batch and continuous cultivation experiments using a pressurizable airlift loop reactor. At Oxygen partial pressures of more than 1000 mbar growth of M. Clara is retarded and completely inhibited at 1200 mbr. However, after several hours of incubation at elevated oxygen partial pressures, biomass formation is nearly doubled in subsequent continuous operation, Cells pretreated with oxygen are characterized by a change of cytochrome content; they excrete carboxylic acids into the medium. The results indicate that, by sparging an aerobic culture intermittently with pure oxygen, formation of biomass might be enhanced. (c) 1992 John Wiley & Sons, Inc.