Effect of fermentation conditions on N

Zhivotchenko, A. G.; Nikonova, E. S.; Jørgensen, M.H.

doi:10.1007/s004490050177

Cited by 2 publications

(4 citation statements)

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“…In the presence of ammonium, N 2 fixation was not expected. Cells will start to fix N 2 when the availability of nitrogen compounds becomes limiting, as was demonstrated for Methylococcus capsulatus Bath by Zhivotchenko et al (1995). Furthermore, ammonium is an important repressor of the transcription of nif genes, as was observed for diazotrophic species of proteobacteria (Rudnick et al, 1997).…”

Section: N 2 -Fixing Chemostat Culturesmentioning

confidence: 97%

“…This activity represents the induction of the nitrogenase. The 3 h incubation time required before linear ethylene production started was also observed for Methylococcus capsulatus Bath (Zhivotchenko et al, 1995).…”

mentioning

confidence: 91%

“…1a) and favours the 0.5 % O 2 saturation we used for the chemostat culture liquid medium as being optimal for growth under N 2 -fixing conditions. The oxygen requirement for nitrogenase activity for other methanotrophs was 6 % (v/v) for Methylococcus capsulatus Bath, 2 % (v/v) for Methylosinus strain 6 and 0.5-1 % (v/v) for Methylocystis strain T-1 ( Zhivotchenko et al, 1995;Toukdarian & Lidstrom, 1984;Takeda, 1988). If we compare the nitrogenase assay with growth experiments in nitrogen-free medium, no activity of nitrogenase was observed in assays at oxygen concentrations above 1 % (v/v), while growth was observed even at 2 % (v/v) O 2 .…”

Section: Oxygen Optimum Of Solv Nitrogenase Activitymentioning

confidence: 99%

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Nitrogen fixation by the verrucomicrobial methanotroph ‘Methylacidiphilum fumariolicum’ SolV

et al. 2010

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The ability to utilize atmospheric nitrogen (N2) as a sole nitrogen source is an important trait for prokaryotes. Knowledge of N2 fixation by methanotrophs is needed to understand their role in nitrogen cycling in different environments. The verrucomicrobial methanotroph ‘Methylacidiphilum fumariolicum’ strain SolV was investigated for its ability to fix N2. Physiological studies were combined with nitrogenase activity measurements and phylogenetic analysis of the nifDHK genes, encoding the subunits of the nitrogenase. ‘M. fumariolicum’ SolV was able to fix N2 at low oxygen (O2) concentration (0.5 %, v/v) in chemostat cultures. This low oxygen concentration was also required for an optimal nitrogenase activity [47.4 nmol ethylene h−1 (mg cell dry weight)−1]. Based on acetylene reduction assay and growth experiments, the nitrogenase of strain SolV seems to be extremely oxygen sensitive compared to most proteobacterial methanotrophs. The activity of the nitrogenase was not inhibited by ammonium concentrations up to 94 mM. This is believed to be the first report on the physiology of N2 fixation within the phylum Verrucomicrobia.

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Section: N 2 -Fixing Chemostat Culturesmentioning

confidence: 97%

mentioning

confidence: 91%

Section: Oxygen Optimum Of Solv Nitrogenase Activitymentioning

confidence: 99%

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Nitrogen fixation by the verrucomicrobial methanotroph ‘Methylacidiphilum fumariolicum’ SolV

et al. 2010

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“…However, the significant increase in growth when copper was increased to 40 µM in the optimized medium suggests that even though the pMMO was active, the Cu 2+ concentration was still limiting. Zhivotchenko et al (1995) indicated that 6 µM Cu 2+ is the optimum level required for every 1 g/L biomass. Using this correlation for 10.30 g/L biomass concentration resulting from this study, the Cu 2+ requirement would be approximately 62 µM (0.015 g/L).…”

Section: Heterotrophic Bacteriamentioning

confidence: 99%

ENHANCED PRODUCTION OF SINGLE CELL PROTEIN FROM M. capsulatus (BATH) GROWING IN MIXED CULTURE

Nunes¹,

Aufderheide²,

Ramjattan³

et al. 2016

J microb biotech food sci

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The growing global demand for nutritional protein means that a sustainable source such as Single Cell Protein from Methylococcus capsulatus (Bath) can become a potential replacement for fishmeal and other animal feeds. Improving biomass concentrations using statistical optimization during synergistic fermentations with a mixed consortium of the three heterotrophic bacteria Alcaligenes acidovorans, Aneurinibacillus danicus, and Brevibacillus sp. can increase the feasibility of the industrial process. The medium components Mg2+, Ca2+, Fe3+, Cu2+, PO42-, NO3-, MoO42-, trace metals, and process temperature were screened using a two-level Plackett-Burman Design in shake flasks which resulted in Cu2+ being the only significant factor. The optimum level of CuSO4.5H2O was found to be 40 μM using One Factor Response Surface Methodology, which was three times higher than the typical values of Cu2+ used previously. These combined strategies led to a 265% increase in biomass, with final cell concentration of 10.3 g/L, up from 2.8 g/L in fed batch fermentations over 48 hours. The heterotrophic bacteria did not grow on NMS or methane but increased biomass concentration when added to M. capsulatus (Bath) cultures.

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Effect of fermentation conditions on N

Cited by 2 publications

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Nitrogen fixation by the verrucomicrobial methanotroph ‘Methylacidiphilum fumariolicum’ SolV

Nitrogen fixation by the verrucomicrobial methanotroph ‘Methylacidiphilum fumariolicum’ SolV

ENHANCED PRODUCTION OF SINGLE CELL PROTEIN FROM M. capsulatus (BATH) GROWING IN MIXED CULTURE

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