Applying theories of microbial metabolism for induction of targeted enzyme activity in a methanogenic microbial community at a metabolic steady state.
Novel enzymes that are stable in diverse conditions are intensively sought because they offer major potential advantages in industrial biotechnology, and microorganisms in extreme environments are key sources of such enzymes. However, most potentially valuable enzymes are currently inaccessible due to the pure culturing problem of microorganisms. Novel metagenomic and metaproteomic techniques that circumvent the need for pure cultures have theoretically provided possibilities to identify all genes and all proteins in microbial communities, but these techniques have not been widely used to directly identify specific enzymes because they generate vast amounts of extraneous data.In a first step towards developing a metaproteomic approach to pinpoint targeted extracellular hydrolytic enzymes of choice in microbial communities, we have generated and analyzed the necessary conditions for such an approach by the use of a methanogenic microbial community maintained on a chemically defined medium. The results show that a metabolic steady state of the microbial community could be reached, at which the expression of the targeted hydrolytic enzymes were suppressed, and that upon enzyme induction a distinct increase in the targeted enzyme expression was obtained. Furthermore, no cross talk in expression was detected between the two focal types of enzyme activities under their respective inductive conditions. Thus, the described approach should be useful to generate ideal samples, collected before and after selective induction, in controlled microbial communities to clearly discriminate between constituently expressed proteins and extracellular hydrolytic enzymes that are specifically induced, thereby reducing the analysis to only those proteins that are distinctively up-regulated.
Molecular Biotechnology, Department of Physics, Chemistry and Biology, Linköping University, 581 83, Linköping, Sweden.
Jutta
J
Speda
Molecular Biotechnology, Department of Physics, Chemistry and Biology, Linköping University, 581 83, Linköping, Sweden.
Mikaela A
MA
Johansson
Molecular Biotechnology, Department of Physics, Chemistry and Biology, Linköping University, 581 83, Linköping, Sweden.
Bengt-Harald
BH
Jonsson
Molecular Biotechnology, Department of Physics, Chemistry and Biology, Linköping University, 581 83, Linköping, Sweden. marka@ifm.liu.se.|InZymes Biotech AB, Gjuterigatan 1B, 582 73, Linköping, Sweden. marka@ifm.liu.se.
Martin
M
Karlsson
D003470:Culture Media / Q000737:chemistry; D006867:Hydrolases / Q000378:metabolism*; D008697:Methane / Q000378:metabolism*; D059013:Microbial Consortia; D015533:Transcriptional Activation
D003470:Culture Media; D006867:Hydrolases; D008697:Methane
Biogas; Cellulase; Enzyme discovery; Metaproteomics; Microbial community; Protease