Improving mathematical model in biodegradation of PAHs contaminated soil using gram-positive bacteria
In published literature there are limited studies on the estimation of kinetic parameters of polycyclic aromatic hydrocarbons (PAHs) in soil. In addition, neither the kinetic studies were performed with Gram-positive bacteria nor conducted under non-indigenous condition in order to understand their...
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| Main Authors: | , , , |
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| Format: | Article |
| Published: |
Taylor & Francis Group
2016
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| Subjects: | |
| Online Access: | http://eprints.uthm.edu.my/8559/ |
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| Summary: | In published literature there are limited studies on the estimation of
kinetic parameters of polycyclic aromatic hydrocarbons (PAHs) in soil. In
addition, neither the kinetic studies were performed with Gram-positive
bacteria nor conducted under non-indigenous condition in order to
understand their removal performance. Thus, a mathematical model
describing biodegradation of phenanthrene-contaminated soil by
Corynebacteriumurealyticum, bacterium isolated from municipal sludge,
was developed in this study. The model includes three kinetic parameters
that were determined using TableCurve 2D software, namely
qmax (maximum substrate utilization rate per unit mass of bacteria), X
(biomass concentration) and Ks (substrate concentration at one half
the maximum substrate utilization rate). These parameters were evaluated
and verified in five different initial phenanthrene concentrations.
Highest degradation rate was determined to be 79.24 mg kg¡1 day¡1
at 500 mg kg¡1 initial phenanthrene concentrations. This high concentration
shows that bacteria perform better in contaminated sand compared
to liquid media. High r2 values, ranging from 0.92 to 0.99, were
obtained excluding 1000 mg/kg phenanthrene. The kinetic parameters,
i.e., qmax and Ks, increased with the phenanthrene concentration and
thus suggest that bacteria degrade at a higher degradation rate. This
model successfully described the biodegradation profiles observed at
different initial phenanthrene concentrations. The established model
can be used to simulate the duration of phenanthrene degradation
using only the value of the initial PAHs concentration. |
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