L1 /
2
CH3041
MICROBIAL REDOX
SYSTEMS
• Microorganisms in
water catalyse the
conversion of {CH2O} stepwise back to CO2
using a variety of different electron acceptors (not just O2).
conversion of {CH2O} stepwise back to CO2
using a variety of different electron acceptors (not just O2).
eg.
Nitrogen fixer bacteria DG -56 kJ / mol
2N2 + 4H+ + 3{CH2O} + 3H2O ® 4NH4+ + 3CO2
2N2 + 4H+ + 3{CH2O} + 3H2O ® 4NH4+ + 3CO2
• Through
this means they gain the energy
required to drive their metabolic processes.
required to drive their metabolic processes.
•The oxygen content of water (DO) controls which life-forms exist in the water body.
» Oxic - aerobic
respiration DO > 5 mg/L
» Hypooxic - aerobic die 4 days DO
< 2 mg/L
» Anoxic - anaerobic respiration DO @0
mg/L
• Aerobic
respiration is used as first choice as more E is
provided per mole of {CH2O}.
