Back to Search Start Over

Influence of Metronidazole, CO, CO 2 , and Methanogens on the Fermentative Metabolism of the Anaerobic Fungus Neocallimastix sp. Strain L2

Authors :
Elizabeth Rees
Femke D. Marvin-Sikkema
Marjan N. Kraak
Jan C. Gottschal
Rudolf A. Prins
Source :
Applied and Environmental Microbiology. 59:2678-2683
Publication Year :
1993
Publisher :
American Society for Microbiology, 1993.

Abstract

The effects of metronidazole, CO, methanogens, and CO 2 on the fermentation of glucose by the anaerobic fungus Neocallimastix sp. strain L2 were investigated. Both metronidazole and CO caused a shift in the fermentation products from predominantly H 2 , acetate, and formate to lactate as the major product and caused a lower glucose consumption rate and cell protein yield. An increased lactate dehydrogenase activity and a decreased hydrogenase activity were observed in cells grown under both culture conditions. In metronidazole-grown cells, the amount of hydrogenase protein was decreased compared with the amount in cells grown in the absence of metronidazole. When Neocallimastix sp. strain L2 was cocultured with the methanogenic bacterium Methanobrevibacter smithii , the fermentation pattern changed in the opposite direction: H 2 and acetate production increased at the expense of the electron sink products lactate, succinate, and ethanol. A concomitant decrease in the enzyme activities leading to these electron sink products was observed, as well as an increase in the glucose consumption rate and cell protein yield, compared with those of pure cultures of the fungus. Low levels of CO 2 in the gas phase resulted in increased H 2 and lactate formation and decreased production of formate, acetate, succinate, and ethanol, a decreased glucose consumption rate and cell protein yield, and a decrease in most of the hydrogenosomal enzyme activities. None of the tested culture conditions resulted in changed quantities of hydrogenosomal proteins. The results indicate that manipulation of the pattern of fermentation in Neocallimastix sp. strain L2 results in changes in enzyme activities but not in the proliferation or disappearance of hydrogenosomes.

Details

ISSN :
10985336 and 00992240
Volume :
59
Database :
OpenAIRE
Journal :
Applied and Environmental Microbiology
Accession number :
edsair.doi.dedup.....655b09aa4b88a92de1957e763b37653c
Full Text :
https://doi.org/10.1128/aem.59.8.2678-2683.1993