Expression and characterization of lytic polysaccharide monooxygenases from Myriococcum thermophilum
Master thesis
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http://hdl.handle.net/11250/293718Utgivelsesdato
2015-07-28Metadata
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- Master's theses (KBM) [888]
Sammendrag
In the field of biomass utilization, better enzyme technologies need to be developed
for more efficient production of biofuels, materials and chemicals. In this regard, the
study of the novel oxidative carbohydrate degrading enzymes lytic polysaccharide
monooxygenases (LPMOs) are important. In this master thesis three LPMOs from the
filamentous fungi Myriococcum thermophilum, a cellulose degrading organism with a
genome containing over 20 possible LPMOs, are characterized.
One of these three enzymes, together with its truncated version, was successfully
cloned and expressed in the yeast Pichia pastoris. All three enzymes were characterized
using bioinformatics, chromatography, mass spectrometry and colorimetric analysis.
Important structural elements and activities were investigated and the three enzymes
were compared to each other and to previously characterized LPMOs from other fungi.
By using bioinformatic tools the enzymes were found to most likely belong to three
different subclasses of LPMOs. These classes differ in their structures and sequences
and use slightly different mechanisms for cellulose degradation, forming different
oxidized products. The enzymes showed activity on different substrates and yielded
different products, and these results confirmed affiliation to the three subclasses. It
is interesting and probably important for cellulose degradation in nature that a wide
diversity of these enzymes are found in certain microorganisms. This study adds
new information to the as of now quite limited knowledge base that exists for this
interesting, newly discovered class of enzymes.