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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@fukuoka-u.ac.jp. 1.
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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@fukuoka-u.ac.jp 1
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 MSWincinerationfacilities • - 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
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
1. Introduction 2. Materials and Methods 3. Results and Discussion4. 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
1. Introduction 2. Materials and Methods 3. Results and Discussion4. Conclusions2-2 Experimental condition Influence of soil property - L/S=6 • Influence of Liquid-Solid (L/S) ratio • - 1,3,6,8-TCDD • organic-rich soil
2,7-DCDD or 1,3,6,8-TCDD Simulation of contaminated soil Mixing no addition 0mL(L/S = 6) -2,7-DCDD or or -1,3,6,8-TCDD -Distilled water: 15mL(L/S = 9) 30mL(L/S = 12) 45mL(L/S = 15) Organic-poor soil: 5g (autoclaved) or Organic-rich soil: 5g (autoclaved) 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 (n=3) Liquid-state condition Growth of fungi “Weight analysis” Degradation of dioxins - “2,7-DCDD” - “1,3,6,8-TCDD” Slurry-state condition
1.1% 2,7-DCDD 35.0% 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
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 ?
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
Extraction -24hours -shaking Solvent: distilled water Only soluble matters from organic-rich soil were added into flask 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 (n=3) Growth of fungi “Weight analysis” Degradation of dioxins - “2,7-DCDD”
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
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.
35% 25% 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%
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%
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 washingin advance In order to establish remediation method for soil - to important to consider soil components - to control water content