Fungi for Bioremediation

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Fungi for Bioremediation

• Julie Quinn
• ESM 219

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The Mechanism

• Fungi have ligninase and cellulase enzymes that
  break down woody materials. This allows fungi to
  get the needed carbon and energy they require for
  growth.
• These enzymes are non-specific, meaning they can
  act on substrates like environmental pollutants.

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Physical Mechanism

• Hyphae allow fungi to expand their surface area,
  making it easier to contact the pollutant.
• Extracellular enzymes can then go to work.

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Degradation of Organopollutants

• Phanerochaete chrysosporium, white rot fungi,
  acts to break down pollutants by adding an -OH
  group.
• Hydroxilating makes the compound more polar.

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Pleurotos ostreatus laccase degradation of OP
pesticides and nerve agents
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Hebeloma crustuliniforme

• Fungi used in conjunction with the plant to
  remediate atrazine.

7
PCB degradation by white rot fungi

• PCB volatility, sorption on biological matrices,
  and xenobiotic extraction method were factors
  affecting remediation success.

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Anthracene

• One mechanism to measure the degradation is by
  dye decolorization.
• There was a high correlation between elimination
  of anthracene and Poly R-478 (dye)
  decolorization.
• Interestingly, four strains were able to oxidize
  anthracene to anthraquinone even after HgCl2
  poisoning.

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Biodegradation of Nitro-substituted explosives

• Wood and litter decaying fungi have been shown to
  metabolize TNT, but only a few of the species
  tested to date have been able to mineralize it.
• Problems fungi have to compete with indigenous
  microflora, mineralization rate lower in soil
  than liquid medium, unclear biotransformation
  consequences.

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DNT CO2
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Conclusions

• Fungi can be used to reduce waste streams in
  agriculture, forestry, and paper industries.
• Successful degradation of pollutants via
  non-specific enzymatic activity.

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Questions?