Biomedical Engineering Reference
In-Depth Information
Table 9.1. Apparent First-Order Rates of Carbon Tetrachloride Transformation (k
00
) and Half-Lives
of Carbon Tetrachloride in Mixtures Containing Diverse Cell Types (washed) and Purified Super-
natant Produced by P. stutzeri KC (after Tatara et al., 1995). The CT active agent within the purified
supernatant was later identified as PDTC.
Secreted
PDTC
Added?
b
Growth
Conditions
a
CT Half-life
(minute)
Number
of Samples
k
00
(minute
-1
)
c
Cell Type
Secreted PDTC alone
(No cells present)
Medium D,
aerobic or anoxic
NA
0.03 0.03
67 65
13
Pseudomonas sp.
strain KC
Medium D, anoxic
Yes
0.18 0.05
4.0 1.1
6
Pseudomonas
fluorescens
Medium D,
aerobic
No
0.00
0.00
NA
3
Yes
0.20 0.01
3.4 0.1
3
Nutrient broth
No
0.00
0.00
NA
3
Yes
0.10 0.00
7.2 0.2
3
Pseudomonas stutzeri
Medium D,
aerobic
No
0.00
0.00
NA
3
Yes
0.15 0.00
4.5 0.0
3
Escherichia coli K-12
Medium D,
glucose, aerobic
No
0.00 0.00
NA
3
Yes
0.06 0.01
12 1
3
Bacillus subtilus
Nutrient broth
No
0.00 0.00
NA
3
Yes
0.04
0.01
19
3
3
Schoolcraft consortium
(SC-1)
Medium D,
aerobic
No
0.00 0.00
NA
3
Yes
0.25
0.01
2.8
0.1
3
Medium D, pH 7,
10
m
M Fe, aerobic
No
0.00 0.0
NA
3
Yes
0.28
0.03
2.5
0.3
3
Hanford consortium
(HC-14)
SGW pH 7.5
anoxic
No
0.00 0.00
NA
3
Yes
d
0.25 0.02
2.7 0.2
3
Saccharomyces
cerevisiae
Yeast medium
No
0.00 0.00
NA
3
Yes
d
0.12 0.01
5.8 0.5
3
a
All cells were grown at pH 8.2 unless otherwise noted
b
Secreted PDTC added as 500 molecular weight (MW) filtrate unless otherwise noted
c
Represents the standard deviation of the designated n number of samples
d
Secreted PDTC added as 10,000 MW filtrate
After Tatara (
1996
) realized that different cell types could be combined with partially
purified cell-free supernatants from strain KC to regenerate PDTC, he developed a bioassay for
the then unknown secreted activity. In his bioassay, which evidently assays the PDTC-Cu
complex, Tatara (
1996
) added washed
P. fluorescens
cells to supernatant samples produced
by strain KC, added CT, and monitored the rate of CT degradation. These assays confirmed
that the rate of CT degradation is directly proportional to the concentration of added cells, up to
a saturation cell concentration of ~10
8
colony forming units/milliliter (cfu/mL). Additional
studies are needed to determine rate constants for the pure PDTC-Cu complex in the presence
and absence of cells.
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