A comparison of the growth ofDesulfovibrio vulgaris under a hydrogen and under an inert atmosphere

Abstract

SUMMARYThe growth of the Hildenborough strain of Desulfovibrio vulgaris has been studied ill stirred cultures flushed withAr/CO2 (95 + 5)and H2/CO2 (95 q-5). Sodium lactate was used as the carbon-energy source with sodium sulphate as the terminal electron acceptor. The initial lactate concentration was varied in defined media (pH 7) augmented with 0.5 mM citrate as chelating agent, and growth was followed to completion. Yields were calculated for the region of strict lactate limitation, i.e. where the total growth was directly proportional to the initial lactate concentration.The maximum specific growth rate was identical for both gases (0.15 h -1) ; however, the yield under hydrogen was 25.8 :k 2.1 g/mole of lactate compared with 9.20 ~ 0.78 g/mole under argon (95% confidence limits). No growth occurred in the absence of sodium lactate. The total protein contents of the cells were similar in both cases (67-75 per cent).In addition the organism was grown under a hydrogen atmosphere ill medium augmented with 0.01 per cent yeast extract. This concentration of yeast extract was estimated to provide a sufficient exogenous supply of amino acids for cell biosynthesis at the expected levels of cell density. Although a significant increase in the growth rate was observed (0.20 h -1) the yield was only marginally improved (28.2 ± 2.7 g/mole) In the absence of lactate the residual growth (7 mg/1) was explained by the utilisation of substances in the yeast extract as energy source. Isobutanol was tested as an energy source under both nitrogen and hydrogen in media augmented with 0.02 per cent yeast extract. The marginal growth that occurred was again explained by the utilisation of some component of the yeast extract as energy source.

Occurrence of sulphate‐reducing bacteria in human faeces and the relationship of dissimilatory sulphate reduction to methanogenesis in the large gut

“…Postgate's medium 'E' (Postgate 1984) was used to estimate viable populations of lactate, pyruvate, ethanol, succinate, valerate, formate and glutamate/serine/alanine-utilizing SRB. To overcome the possible toxic effect of sodium thioglycollate to certain species (Khosrovi & Miller 1975). this compound was omitted from the basal medium and an increased concentration of sodium ascorbate was used as the sole reducing agent (Battersby et al 19135).…”

Microcalorimetric studies of the growth of sulfate-reducing bacteria: energetics of Desulfovibrio vulgaris growth.

“…The growth energetics of sulfate-reducing bacteria have already been studied by assessment of molecular growth yields (15,16,25); the purpose of this work was to study the growth of D. vulgaris by using microcalorimetric techniques. These techniques have been developed by Belaich et al (5,7) and are very convenient for this study of anaerobic growth (3,4).…”

A simple most probable number method for the enumeration of sulphate‐reducing bacteria in biocide containing waters

“…Such reduced conditions are usually created by the addition of thioglycollate to the growth medium (Postgate 1979). Unfortunately this compound is inhibitory to many SRB strains (Khosrovi & Miller 1975) resulting in their poor recovery from injection waters, ballast tanks and other samples. Media such as that recommended by the American Petroleum Institute (Anon.…”