Batch cultivation of Methylosinus trichosporium OB3b. 4: Production of hydrogen-driven soluble or particulate methane monooxygenase activity
- Lawrence Livermore National Lab., CA (United States)
Batch culture conditions were established for the formation of H{sub 2}-driven whole-cell soluble or particulate methane monooxygenase (sMMO or pMMO) activity in the obligate methanotroph, Methylosinus trichosporium OB3b, to expand its potential uses in groundwater bioremediation and the production of specific chemicals. Addition of either Ni and H{sub 2} to a nitrate-containing minimal salts growth medium or Ni and Mo to a nitrate-lacking growth medium (induces a nitrogenase that generates intracellular H{sub 2}) markedly enhanced both the hydrogenase and the accompanying washed-cell H{sub 2}-driven MMO activities of shake-flask cultured cells. For sMMO containing cells, H{sub 2} provided in vitro reducing power for the oxidation of chlorinated solvents such as chloroform and trichloroethylene. Cell cultivations under N{sub 2}-fixing conditions in a 5-L bioreactor, however, required an initial nitrate concentration of at least 1 to 2 mM to achieve high biomass yields (5 to 7 g of dry cell wt/L) for cells producing H{sub 2}-driven sMMO or pMMO activity. Elevation of the initial medium nitrate concentration to 20 mM shortened the culture time for pMMO producing cells by 40%, yet still generated an equivalent growth yield. High nitrate also shortened the culture time for sMMO containing cells by {approximately}25%, but it lowered their biomass yield by 26%. Upon storage for 5 weeks at room temperature, washed resting-state cells retained 90% and 70% of their H{sub 2}-driven sMMO and pMMO activity, respectively. This makes their practical use quite feasible.
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 395133
- Journal Information:
- Biotechnology and Bioengineering, Journal Name: Biotechnology and Bioengineering Journal Issue: 3 Vol. 45; ISSN 0006-3592; ISSN BIBIAU
- Country of Publication:
- United States
- Language:
- English
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