This document discusses biodegradation and provides examples. It covers: 1) Biodegradation can occur through mineralization, where organic compounds are broken down into carbon dioxide, water and inorganic compounds, or through biotransformation, where the compound is transformed but not fully degraded. 2) The biodegradation of fats and oils proceeds through beta oxidation, where two carbon units are removed in each step to break down the fatty acid into acetyl-CoA units. 3) Detergents have varying degrees of biodegradability, from readily biodegradable soaps and fatty acids to more resistant polymers and alkylbenzene sulfonates, though linear alkylbenzene sulfonates

1. GREEN TECHNOLOGY (Environmental Science)
SUB Code: CH104
Dr. Aniruddha Paul
NATIONAL INSTITUTE OF TECHNOLOGY PATNA
DEPARTMENT of CHEMISTRY
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2. UNIT 4: WATER and BIODEGRADATION
Biodegradation
A. Mineralization:
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3. B. Biotransformation:
Example 1.
Example 2.
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4.  Biodegradation: Some General rules
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 Biodegradation: Some General rules

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 Biodegradation: Some General rules

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 Biodegradation: Some General rules

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 Biodegradation: A list of transformation reactions
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 In both cases the first stage is formation of pyruvic acid from simple hexose (like
glucose)

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that .

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The acids can undergo further degradation, as shown in next section.

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• The biodegradation of fats is difficult and is restricted by their limited solubility.
• Oxidation occurs at β carbon atom – and proceeds in a series of steps.
• Coenzyme A actively participate in this transformation.
Step 1.
α
β

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Step 2. Hydrogen removed from β carbon (Dehydrogenation)
Step 3. Hydroxylation at β carbon
α
β
α
β
α
β
α
β

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Step 4. Dehydrogenation
α
β
Step 5. Hydrolysis (α-β bond cleavage)
α
β
α
β
Original molecule of acid appears with as a new acid derivative with
2 less carbon atoms.

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 β oxidation of palmitic acid would proceed by “chopping off’ two carbons at a time in
the form of acetic acid.
 Since the acid has total 16 carbons, a total 8 moles of acetic acid will be formed for
each mole of palmitic acid. (7 cycles)
Example: β Oxidation of Palmitic Acid (C15H31COOH)
Biodegradation of detergents
• Some are readily biodegradable: Common soaps, fatty acids, sulfated alcohols, esters etc.
• Others have moderate to severe Bio resistivity: polymers of ethylene oxide (moderate), alkyl
benzene sulfonates derived from propene (highly resistant).
• Linear alkyl benzene sulfonates (LAS) are biodegradable alternative for most hazardous
detergents.