Biomedical Engineering Reference
In-Depth Information
12.3.3
HPLC analysis
Molecular weights of PEG before and after cultivation were measured by a Tosoh
HPLC ccp&8020 equipped with Tosoh TSK-GEL G2500 PW (7.5
300 mm) with
0.3 M sodium nitrate at 1.0 mL/min at room temperature. Detection was done with
an RI detector (Tosoh RI-8020) (Figure 12.2). The molecular weights were calcu-
lated with authentic PEG standards (Figure 12.3). Figure 12.4 shows HPLC pro-
fi les of PEG before and after cultivation of microbial consortium E-1 based on the
HPLC outputs and the PEG standards.
ϕ
×
12.3.4
Numerical Study of Exogenous Depolymerization
Mathematical model (12.1) is appropriate for the depolymerization processes
under a steady microbial population. However, the change of microbial population
should be taken into account over a period in which a microbial population is still
in a developing stage. In such cases, the degradation rate should be time depend-
ent in the modeling of exogenous depolymerization processes:
d
d
x
t
M
ML
y
=−
β
(,
tMx
)
+
β
(,
tM
+
L
)
(12.6)
+
DAY 0
DAY 1
DAY 3
DAY 5
DAY 7
DAY 9
400
300
200
100
0
10
20
30
Min
Figure 12.2
HPLC outputs of PEG before and after the cultivation of the microbial consortium
E - 1.
