Growth inhibition by soil components for degradation of dioxins using white rot fungus

1. 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

2. 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

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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 ?

9. 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

10. 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”

11. 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

12. 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.

13. 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%

14. 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%

15. 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

16. Thank you very much for your attention !