Biodegradation of aromatic compounds bioremediation

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APPLICATIONS OF MICROBES
Biodegradation of aromatic compounds/
bioremediation
- Evolved mechanisms of degradation -
Inexpensive - Ease of handling - Natural process
of remediation
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Applications of Aromatic Compounds

• Synthetic textile fibers
• Building and construction products
• Automobiles and paints
• Toy and Cosmetic industry
• Medical devices

• Household fumigant, such as in mothballs
• Chemical intermediate to produce other chemicals
  (phthalate anhydride and carbaryl)
• Preparation synthetic dyes

• Chiefly used as insecticide

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Toxicity of Aromatic compounds

• Phthalates
• Plasticizer leaches out by various organic
  solvents and biological fluids
• Shorter chain esters More toxic
• Reported to be teratogenic, estrogenic and
  mutagenic
• Suppressed calcium signaling in nicotinic
  acetylcholine receptors

• Naphthalene
• Exposure to large amounts of naphthalene cause
  nausea, vomiting, diarrhea, blood in the urine,
  and jaundice
• The International Agency for Research on Cancer
  (IARC) classifies naphthalene as possibly
  carcinogenic to humans Group 2B
• acute exposure causes cataracts in humans, rats,
  rabbits, and mice and hemolytic anemia in
  children and infants

• Carbaryl
• It is a cholinesterase inhibitor and toxic to
  humans with excessive exposure

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Aromatic compound metabolism

• Growth of an organism on the PAH substrate
• Mineralization of the PAH substrate in the
  absence of detectable growth
• Transformation of the PAH substrate to
  non-mineral, terminal products

Microorganisms
Bacteria completely degrade or
co-metabolize Fungi - transformation Algae -
transformation
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Ring Hydroxylating Dioxygenases
NADH
NAD
Ring cleavage Dioxygenases
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• - Isolating and identification
• of metabolites
• Biotransformation studies
• - Whole-cell Oxygen uptake
• - Enzyme activity studies