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Sampling site where Streptomyces sp. PCB7 - the first microorganisms demonstrating the ability to oxidize atmospheric H2 - was isolated.
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Soil uptake of atmospheric H2 — discovery of the missing link
The isolation of several Streptomyces demonstrating the ability to oxidize atmospheric H2 constitutes a major breakthrough in the field of H2 biochemistry. This discovery challenged a controversial concept in microbiology since the soil uptake of atmospheric H2 was previously attributed to the occurrence of free soil hydrogenases. Microcosms will be deployed in the laboratory to analyze the environmental control on the expression and activity of high affinity [NiFe]-hydrogenases. Critical environmental parameters influencing high affinity H2 oxidation activity will be indentified in controlled environments, allowing the establishment of conceptual models to be tested by strategic field investigations realized in contrasting ecosystems.
Long-term objective: Predict the impact of global change on the budget of atmospheric H2.
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CARD-FISH to visualize the expression of high affinity hydrogenase in the spores of Streptomyces sp. PCB7.
Image: Jennifer Pratscher.
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Characterization of a hydrogenase demonstrating unusual properties
We are currently employing Streptomyces avermitilis as a model microorganism to shed light on the physiological role, regulation and biochemical properties of high affinity [NiFe]-hydrogenases. An inducible over-expression system is being developed, allowing us to undertake the first biochemical characterization of high affinity [NiFe]-hydrogenase. The purified recombinant hydrogenase will be challenged to evaluate the optimal conditions and the potential limitations for the operation of the biocatalyst - a mandatory step to assess the biotechnological application of high affinity hydrogenases.
Long-term objective: Improve the yield of secondary metabolites production, biodegradation and other bioprocesses with the energy generated by a recombinant high affinity hydrogenase.
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◄ Arrangement of the auxiliary and structural genes of the putative high affinity [NiFe]-hydrogenase in S. avermitilis.
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Liliana measuring the soil uptake of atmospheric CO.
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Other trace gases
An automated sampling system will be deployed to monitor the oxidation of carbon monoxide (CO) and carbonyl sulphide (COS) in microcosms. The microorganisms displaying the ability to oxidize these trace gases will be enriched, identified and isolated. Novel enzymes displaying unusual properties will be identified and the ecophysiology of microorganisms responsible for the soil sink of CO and COS will be investigated.
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