Bioremediation
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Author’s profile
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Background
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Executive Summary
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Paper 1 ( Zhang et
al.)
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Paper 2 (Wang et al.)
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Table 2
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Comparison
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Critical comment
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Personal comment
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Reference
Author’s profile
Hi, my name is Guanchen Zhu. I’m an undergraduate student in biomedical
science and this is my last year of study.
When mentioned about the crude oil spilling, I always feel that’s far away from
me. However the spillage of petroleum happened a few years ago in my home
town impressed me especially when I saw those beautiful and crowded beach
suddenly became such a cold and cheerless place which covered with black,
sticky and smelly oil…
It’s said that even though most of the oil has been removed, the remaining
could require more than a decade to recover. So I’m so worried about it and
looking for a way that could solve it faster. Could this method be
biodegradation?
http://www.boston.com/bigpict
ure/2010/07/oil_spill_in_dalian_
china.html
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Author’s profile
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Background
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Executive Summary
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Paper 1 ( Zhang et
al.)
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Paper 2 (Wang et al.)
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Table 2
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Comparison
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Critical comment
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Personal comment
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Reference
Background
Petroleum is a mixture of hydrocarbons of various molecular weights and
other organic compounds. According to their carbon structures, the
compositions can be divided into alkanes, cycloalkanes, aromatics and
asphaltene and most of them are saturated hydrocarbons alkanes and
cycloalkanes.
Bioremediation is an acceleration of the natural fate of oil pollutants and
hence a natural or ‘green solution’ to the problem of oil pollutants that
causes minimal ecological effects (Ronald, 1995). Bioremediation is
recognized as an efficient, economic and versatile alternative to
physicochemical treatment. During the last decade, bioremediation has
attracted much attention and new strains with faster degrading has been
identified (Zhang et al, 2010)
However even though low-molecular-weight molecules are found to be
readily degraded by many micro-organisms, long-chain alkanes and
polycyclic aromatic hydrocarbons (PAH) are generally considered to be only
slightly biodegradable due to their higher hydrophobicity (Kanaly and
Harayama, 2000). Since then, exploiting more efficient micro-organisms has
become central to petroleum microbiology.
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Author’s profile
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Background
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Executive Summary
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Paper 1 ( Zhang et
al.)
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Paper 2 (Wang et al.)
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Table 2
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Comparison
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Critical comment
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Personal comment
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Reference
Executive summary
In both of the papers, new strains were found
and isolated which has greater capability of
degrading petroleum.
Degradation of high-molecular-weight molecules
in the petroleum and the strains with wide range
of degrading diversity and efficiency are currently
the central problems in petroleum remediation.
Pseudomonas aeruginosa DQ8 is able to degrade
n-alkanes and polycyclic aromatics.
While the noval Dietzia strain is capable of
degrading wide range of petroleum
hydrocarbons(C6-C40)
Degradation of n-alkanes and polycyclic aromatic hydrocarbons in
petroleum by a newly isolated Pseudomonas aeruginosa DQ8
Zhengzhi Zhang, Zhaowei Hou, Chunyu Yang, Cuiqing Ma, Fei Tao, Ping Xu
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Author’s profile
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Background
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Executive Summary
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Paper 1 ( Zhang et
al.)
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Paper 2 (Wang et al.)
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Table 2
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Comparison
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Critical comment
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Personal comment
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Reference
In the present study, the gram negative pseudomonas aeruginosa strain,
designated as DQ8, was isolated from oil-contaminated soils.
The results of capability of degradation showed that DQ8 is able to
significantly degrade the crude oil in MBSM containing 10% of crude oil, a
part of the crude oil when MBSM was supplemented with 25% crude oil in
10 days. The degradation activities were confirmed by the experiments of
degrading pure n-alkanes and PAH which both gave the positive results. In
this research, the end product of metabolic pathway of n-alkane were
octadecanoic acid and hexadecanoic acid. The end product of metabolic
pathway of PAH were 9-fluorenol, 9-fluorenone, 3-propanoic acid, 2- acetic
acid and 1- indanone.
These results indicated that this newly isolated P. aeruginosa DQ8 could
grow with crude oil as the sole carbon and energy source and degrade the
oil efficiently. Two major components of the crude oil, n-alkane and PAHs
were both tested to be degraded by P. aeruginosa DQ8. Therefore, P.
aeruginosa DQ8 may be of great significance of bioremediation of
petroleum pollution.
Degradation of petroleum hydrocarbons (C6–C40) and
crude oil by a novel Dietzia strain
Xingbiao Wang, Changqiao Chi, Yong Nie, Yueqin Tang, Yan Tan, Gang Wu,
Xiaolei Wu.
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A novel strain, DQ12-45-1b was selected and isolated
from the oil-pollutated waster water due to its good
Author’s profile
ability of alkane degradation in the cultivation. In the
Background
following study of this strain, growth of DQ12-45-1b
was observed in the medium with different pure carbon
Executive Summary
sources. The result was shown in Table 1. When nPaper 1 ( Zhang et
alkanes (C6-C40) and other compounds were tested as
al.)
the sole carbon sources for strain DQ12-45-1b, growth
Paper 2 (Wang et al.) was observed in all cases even though the growth
under some of the carbon sources was slower ( in Table
Table 2
2). Also, a different alkane utilization pattern was
observed.
Comparison
Thus, this novel Dietzia strain was demonstrated able to
Critical comment
grow and utilize alkane from C6-C40 and aromatic
Personal comment
compounds as the sole carbon sources. The unique
pattern of alkane utilization also suggests a novel longReference
chain alkane oxidation pathway exists.
Table 1
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Author’s profile
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Background
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Executive Summary
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Paper 1 ( Zhang et
al.)
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Paper 2 (Wang et
al.)
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Table 2
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Comparison
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Critical comment
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Personal comment
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Reference
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Author’s profile
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Background
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Executive Summary
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Paper 1 ( Zhang et
al.)
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Paper 2 (Wang et
al.)
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Table 2
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Comparison
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Critical comment
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Personal comment
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Reference
Comparison of two papers
P. aeruginosa DQ8 (Zhang et al.) and DQ12-45-1b (Wang et al.)
isolated were both capable of degrading long-chain
hydrocarbons.
The ability of growing under different molecular weight of
carbon sources was tested and demonstrated in Wang. But
there was no data supports capability of degrading wide range
of alkanes in Zhang even though it was mentioned.
The efficiency of degradation was tested with both pure
supplements and crude oil. Both of the strains were
demonstrated to be able to degrade long-chain hydrocarbons
which were considered as the most difficult part of
bioremediation.
Lastly, the metabolic pathway of the p.aeruginosa DQ8 was
described but the metabolic pathway of DQ12-45-1b was not
clarified due to the purpose of a novel pathway.
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Author’s profile
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Background
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Executive Summary
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Paper 1 ( Zhang et
al.)
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Paper 2 (Wang et al.)
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Table 2
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Comparison
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Critical comment
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Personal comment
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Reference
Critical comment
Both of the scientific work were done in high quality.
Controls were properly used and blanks were subtracted.
In Zhang et al, the authors claimed that P.aeruginosa DQ8
was able to degrade wide rage of petroleum compounds.
Even though authors mentioned about the short-chained
hydrocarbons were completely degraded, no detailed
data was provided to prove the diversity of the capability
of degradation. Perhaps this was not the important point
of the paper.
In Wang et al. the end product was not tested and the
metabolic pathway they proposed was not a ordinary
pathway. We could not predict the end product of DQ1245-1b’s metabolism.
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Author’s profile
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Background
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Executive Summary
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Paper 1 ( Zhang et
al.)
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Paper 2 (Wang et al.)
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Table 2
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Comparison
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Critical comment
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Personal comment
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Reference
Personal comment
Petroleum spill causes disastrous damage to the
local environment, marine ecology and fishery. Due
to uncertain factors, accidents could not always be
avoided. Thus efficient and eco-friendly methods of
cleaning up the pollutants is very important and
necessary for us.
The other issue I considered was that if the end
product of the bioremediation would cause another
environmental issue because what I noticed is that
the most of the end products were acids. Will they
again disrupt the ecology further?
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Author’s profile
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Background
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Executive Summary
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Paper 1 ( Zhang et
al.)
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Paper 2 (Wang et
al.)
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Table 2
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Comparison
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Critical comment
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Personal comment
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Reference
Reference
1. Atlas, R.M. (1995). Bioremediation of Petroleum
Pollutants. International Biodeterioration &
Biodegradation (1995) 317-327
2. Zhengzhi Zhang, Zhaowei Hou, Chunyu Yang, Cuiqing
Ma, Fei Tao, Ping Xu (2010). Degradation of n-alkanes
and polycyclic aromatic hydrocarbons in petroleum by
a newly isolated Pseudomonas aeruginosa DQ8.
Bioresource Technology 102 (2011) 4111-4116
3. Xingbiao Wang, Changqiao Chi, Yong Nie, Yueqin Tang,
Yan Tan, Gang Wu, Xiaolei Wu (2011)Degradation of
petroleum hydrocarbons (C6–C40) and crude oil by a
novel Dietzia strain. Bioresource Technology 102 (2011)
7755-7761