Environmental Engineering Reference
In-Depth Information
Table 2
Hydrogenotrophic homoacetogens and methanogens isolated from various environments
Microorganism
Growth temp
(ºC)
Optimum temp
(ºC)
References
Acetobacterium
bakiia
1-30
20
Sediments of a
polluted pond
Kotsyurbenko et al.
(
1995
)
Acetobacterium
paludosuma
1-30
20
Sediments of a fen
Kotsyurbenko et al.
(
1995
)
Acetobacterium
fumetariuma
1-35
30
Manure digested at
low temp
Kotsyurbenko et al.
(
1995
)
Acetobacterium
tundraeb
1-30
20-25
Tundra wetlands
Simankova et al.
(
2000
)
Methanogenic
strain MSB
1-32
25-30
Sediments of a
polluted pond
Kotsyurbenko et al.
(
2001
)
Methanogenic
strain MSP
4-35
25-30
Sediments of a
polluted pond
Kotsyurbenko et al.
(
2001
)
Methanobacterium
strain MB4
5-30
25-30
Peat samples
Kotsyurbenko et al.
(
2007
)
the group contribution factors of S-, N-, or P-atom-containing functional groups
and the Taft constant,
σ
*
, is observed (
r
=
0.99) (Fig.
2
) (Karelson
2000
). The
X
R
i
values for S-, N-, or P-atom-containing functional groups are greater than
those of the alkyl, oxygenated, and halogenated functional groups (Fig.
2
).
This suggests that S-, N-, or P-atom-containing functional groups donate more
electrons toward the neighboring C-H bond(s), thereby enhancing the H-atom
abstraction by HO
•
.
The GCM includes 66 group rate constants and 80 group contribution factors,
which characterize each HO
•
reaction mechanism with steric effects of the chemi-
cal structure groups and impacts of the neighboring functional groups, respectively
(Minakata et al.
2009
). The group contribution factors for H-atom abstraction and
HO
•
addition to the aromatic compounds linearly correlate with the Taft constants,
σ
*
, and the electrophilic substituent parameters,
σ
+
, respectively. The best calibra-
tions for 83 % (257 rate constants) and predictions for 62 % (77 rate constants)
of the rate constants are within 0.5-2 times the experimental values. Literature-
reported experimental HO
•
rate constants for 310 and 124 compounds are used for
calibration and prediction, respectively.
Although there are a few tools available to determine aqueous phase hydroxyl radi-
cal reaction rate constants (Minakata et al.
2011
; Herrmann
2003
; Monod et al.
2005
;
Minakata and Crittenden
2011
; Herrmann et al.
2010
), the GCM is quoted as “The
wide application range in combination with the user-friendliness makes it probably
the best currently available estimation tool for HO radical reactions in aqueous solu-
tion. Overall, the method of Minakata et al. (
2009
) is currently the most broadly usable
method for the prediction of HO radical reaction rates in aqueous solution (Herrmann
et al.
2010
). The GCM peer-reviewed paper provided both MS Excel spread sheet and
compiled Fotran program as supportion information. Any users are able to access these
programs and determine the aqueous phase HO
·
reaction rate constants with inputs of
structural information of a compound of interest.
