Growth inhibition by soil components

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Growth inhibition by soil components for
degradation of dioxins using white rot fungus
Shinya Suzuki, Ayako Tachifuji, Yasushi
Matsufuji Department of Civil Engineering,
Fukuoka University 8-19-1 Nanakuma, Johnan-ku,
Fukuoka, 814-0180 Japan E-mail
ssuzuki_at_fukuoka-u.ac.jp
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1. Introduction 2. Materials and Methods 3.
Results and Discussion 4. Conclusions1-1
Background in Japan

• Dioxin compound
• - risk to cause long-term contamination in soil
• - chemically stable structure
• - accumulate in environment
• 2) There are still many contaminated soils
• - not only around MSW incineration facilities
• - but also around rice field
• - included in pesticide as impurities about 40
  years ago
• 3) Physicochemical treatment methods
• - already developed, but
• - disadvantage from economic and energetic point
  of view

4) So, for remediation of contaminated soil -
which has low concentration of dioxins - more
effective to use bioremediation method
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1. Introduction 2. Materials and Methods 3.
Results and Discussion 4. Conclusions1-2
Objective
In particular, - method using white rot fungi
attracts attention - but living spheres of such
fungi are usually in dead trees, fallen trees,
etc. It is still unclear whether - such fungi
can survive and degrade dioxins in soil
environment.
Objective of this study - to accomplish
effective bioremediation method - for low
levels of dioxins contaminated soil - by using
Phlebia brevispora - to clarify inhibitory
factor of soil components - to evaluate
relationship between growth of fungi and
degradation of dioxins
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1. Introduction 2. Materials and Methods 3.
Results and Discussion 4. Conclusions2-1
Materials

• 1,3,6,8-TCDD
• main components
• of CNP/PCP
• originating dioxins
• longer incubation period

Phlebia brevispora (TMIC 33929) - can degrade
1,3,6,8-TCDD - maintained on potato dextrose
agar (PDA) medium

• 2,7-DCDD
• degraded easily,
• shorter incubation period
• simplified extraction

Soils composed from various materials such as
clay minerals, organic substances - to
compare difference of degradability according to
organic substances
Organic-poor soil
Organic-rich soil
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1. Introduction 2. Materials and Methods 3.
Results and Discussion 4. Conclusions2-2
Experimental condition
Influence of soil property - L/S6

• Influence of Liquid-Solid (L/S) ratio
• - 1,3,6,8-TCDD
• organic-rich soil

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1. Introduction 2. Materials and Methods 3.
Results and Discussion 4. Conclusions2-3
Analytical procedure
Pre Incubation
Incubation
-Fungus body
- Incubation 14 or 30days -Temp. 25? -shaking
every time
-Kirks HCLN medium 30mL (autoclaved)
-Incubation 5days -Temp. 25?
Analysis (n3)
Liquid-state condition
Growth of fungi Weight analysis
Degradation of dioxins - 2,7-DCDD -
1,3,6,8-TCDD
Slurry-state condition
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1. Introduction 2. Materials and Methods 3.
Results and Discussion 4. Conclusions3-1-1)
Influence of soil property L/S 6
12.7
76.3
66.1
- monohydroxy-DCDD, monomethoxy-DCDD were
obtained as metabolite
Degradation rate of 1,3,6,8-TCDD only 1.1 in
slurry-state with organic-rich soil
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1. Introduction 2. Materials and Methods 3.
Results and Discussion 4. Conclusions3-1-2)
Liquid-solid ratio 1,3,6,8-TCDD in organic-rich
soil
1.1
18.9
32.2
27.0
Dissolved matters from organic-rich soil had
inhibition activity? - this improvement probably
caused by dilution of inhibition material in the
soil ?
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1. Introduction 2. Materials and Methods 3.
Results and Discussion 4. Conclusions3-2-1) Soil
extraction
So, in order to examine inhibition activity of
soluble matters only - organic-rich soil was
washed in advance to fractionate into,
organic-rich soil
dissolved matter
washed organic-rich soil
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1. Introduction 2. Materials and Methods 3.
Results and Discussion 4. Conclusions3-2-2)
Analytical procedure
Pre Incubation
Incubation
2,7-DCDD
-Fungus body

• Incubation
• 14days
• -Temp. 25?
• -shaking
• every time

-Kirks HCLN medium 30mL (autoclaved)
-Incubation 5days -Temp. 25?
Analysis (n3)
Growth of fungi Weight analysis
Degradation of dioxins - 2,7-DCDD
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1. Introduction 2. Materials and Methods 3.
Results and Discussion 4. Conclusions3-2-3)
Growth and degradation rate
In case of dissolved matters, growth amount of
fungus much smaller - Growth inhibition was
clearly confirmed during pre-incubation period
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1. Introduction 2. Materials and Methods 3.
Results and Discussion 4. Conclusions3-2-4)
Relationship growth amount v.s. degradation rate
Degradation rate of dioxins in liquid-state only
depended on growth amount - soluble matters from
organic-rich soil had growth inhibition
activity, - it was a part of whole inhibitory
effect from organic-rich soil.
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1. Introduction 2. Materials and Methods 3.
Results and Discussion 4. Conclusions3-2-5)
Influence of growth inhibition
Difference of degradation rate of 2,7-DCDD -
between organic-rich soil and no soil was
about 60, - growth inhibition about 35,
other inhibition about 25
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1. Introduction 2. Materials and Methods 3.
Results and Discussion 4. Conclusions4-1
Conclusions
Growth inhibition by soil components For
degradation of dioxins using white rot
fungus
1) Degradation rate of 1,3,6,8-TCDD - only
1.1 in case of organic-rich soil - increased
according to change liquid-solid ratio
2) Organic-rich soil has large inhibition
activity - soluble matters has growth inhibition
effect
3) Difference of degradation rate of 2,7-DCDD
between with and without organic-rich soil
about 60 - of this, growth inhibition accounted
for about 35
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1. Introduction 2. Materials and Methods 3.
Results and Discussion 4. Conclusions4-2
Conclusions
- Water content most important factor in
remediation of contaminated soil - This
improvement in degradation of dioxins - probably
caused by dilution of growth inhibition material
in soil - In fact, degradation of dioxins
increased by soil washing in advance
In order to establish remediation method for
soil - to important to consider soil
components - to control water content
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Thank you very much for your attention !