Experimental Study of Biodegradation of Ethanol and Toluene Vapors

5-7) (Gaudy, 1980, See Appendix A-I). Acetyl-CoA is oxidized through the TCA
pathway that generates NADH 2 (Equation 5-8).
CH
3
CH
2OH
+ NAD → NADH
2
+ CH
3CHO
(5-5)
CH + +
(5-6)
3CHO
NAD + H
2O
→ CH
3COOH
NADH
2
CH
3
COOH + ATP + CoASH → CH
3COSCoA
+ H
2O
+ ADP
(5-7)
Acetyl-CoA
In the TCA cycle (See Appendix A-II),
CH COSCoA 4 NAD + 3H
O → 4NADH
+ CO + CoASH (5-8)
3
+
2
2
2
2
The overall, general catabolic equation of ethanol oxidation can be derived
based on the above pathways (Geurts et al., 1980; Roels, 1983; see also Appendix A-I):
C H O + ATP 3H
O NAD CO + NADH
(5-9)
2 6
+
2
+ 6 → 2
2
6
2
This equation can be written in terms of 1 C-mol of ethanol as:
-CH 3 O 0.5 - ½ ATP - 2
3
H2 O -3NAD + CO 2 + 3 NADH 2 = 0 (5-10)
(3) Oxidative Phosphorylation
In the oxidative phosphorylation reaction, ATP is produced from the oxidation
of NADH 2 . The amount of ATP produced per electron pair is represented by δ, the socalled
P/O ratio, which represents the efficiency of oxidative phosphorylation. This
process can be represented by:
-NADH 2 - ½ O 2 - δADP + H 2 O + δ ATP + NAD = 0 (5-11)
Please note that the phosphorus molecules are not included in the equations as stated in
note 1 on page 80. The net amount of NADH 2 produced during biomass precursor
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