ISSN:
1432-072X
Keywords:
Key words:Thermotoga maritima– Hyperthermophiles – (Eu)Bacteria – Glucose fermentation – Acetate formation – Embden-Meyerhof pathway – Hexokinase – Phosphofructokinase – Acetate kinase – Sulfur reduction
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract. The hyperthermophilic anaerobic eubacterium Thermotoga maritima was grown on glucose as carbon and energy source. During growth 1 mol glucose was fermented to 2 mol acetate, 2 mol CO2 and 4 mol H2. The molar growth yield on glucose (Yglucose) was about 45 g cell dry mass/mol glucose. In the presence of elemental sulfur growing cultures of T. maritima converted 1 mol glucose to 2 mol acetate, 2 mol CO2 about 0.5 mol H2 and about 3.5 mol H2S. Yglucose was about 45 g/mol. Cell extracts contained all enzymes of the Embden-Meyerhof pathway: hexokinase (0.29 U/mg, 50 °C), glucose-6-phosphate isomerase (0.56 U/mg, 50 °C), phosphofructokinase (0.19 U/mg, 50 °C), fructose-1,6-bisphosphate aldolase (0.033 U/mg, 50 °C), triosephosphate isomerase (6.3 U/mg, 50 °C), glyceraldehyde-3-phosphate dehydrogenase (NAD+ reducing: 0.63 U/mg, 50 °C), phosphoglycerate kinase (3.7 U/mg, 50 °C), phosphoglycerate mutase (0.4 U/mg, 50 °C); enolase (4 U/mg, 80 °C), pyruvate kinase (0.05 U/mg, 50 °C). Furthermore, cell extracts contained pyruvate: ferredoxin oxidoreductase (0.43 U/mg, 60 °C); NADH: ferredoxin oxidoreductase (benzylviologen reduction: 0.46 U/mg, 80 °C); hydrogenase (benzylviologen reduction: 15 U/mg, 80 °C), phosphate acetyltransferase (0.13 U/mg, 80 °C), acetate kinase (1.2 U/mg, 55 °C), lactate dehydrogenase (0.16 U/mg, 80 °C) and pyruvate carboxylase (0.02 U/mg, 50 °C). The findings indicate that the hyperthermophilic eubacterium T. maritima ferments sugars (glucose) to acetate, CO2 and H2 involving the Embden-Meyerhof pathway, phosphate acetyltransferase and acetate kinase. Thus, the organism differs from the hyperthermophilic archaeon Pyrococcus furiosus which ferments sugars to acetate, CO2 and H2 involving a modified non-phosphorylated Entner-Doudoroff pathway and acetyl-CoA synthetase (ADP forming).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00307766
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