Bioremediation of polychlorinated biphenyls (PCBs) using biofilms - - PowerPoint PPT Presentation

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Bioremediation of polychlorinated biphenyls (PCBs) using biofilms - - PowerPoint PPT Presentation

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Bioremediation of polychlorinated biphenyls (PCBs) using biofilms Birthe Veno Kjellerup, Ph.D. University of Maryland at College Park Department of Civil & Environmental Engineering AGENDA Presence and concerns of PCBs? Biological

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Bioremediation of polychlorinated biphenyls (PCBs) using biofilms

Birthe Veno Kjellerup, Ph.D.

University of Maryland at College Park Department of Civil & Environmental Engineering

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SLIDE 2

AGENDA

  • Presence and concerns of PCBs?
  • Biological fate of PCBs?
  • Bioremediation using activated carbon
  • Biofilms in bioremediation
  • Aerobic-anaerobic biofilms in soil
  • Future Research
  • Questions

PCB contaminated soil

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  • rtho

meta para 2 3 4 5 6 2’ 3’ 4’ 5’ 6’

PCBs: Persistent organic pollutants

  • 209 congeners
  • Very Stable
  • Bioaccumulate
  • Toxicity concern
  • Sediments/soils

= global sinks

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SLIDE 4

Microbial transformation of PCBs

Estimated 0.6-1.2 billion kg worldwide

An environmental legacy of PCBs

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Why are PCBs of concern?

  • Bioaccumulates and

biomagnifies in the food chain

  • Present in lipophilic tissue,

blood and breast milk

  • Toxicological effects: Cancer,

problems with endocrine and reproductive organs as well as immunological issues

  • Humans: Source - ingestion

(sea food, meat, poultry etc.)

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The Microbial Fate of PCBs

Aerobic bacterium Burkholderia LB400 Oxygen conc.

Pore water Biofilm on soil particle

<4 Cl subst.: Aerobic PCB degradation

Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl

Cl Cl Cl Cl Cl Cl Cl Cl

Anaerobic bacterium DF1 >4 Cl subst.: Anaerobic PCB dechlorination

Complete mineralization

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SLIDE 7

PCBs - Processes in sediment

Resuspension Biological dechlorination Ingestion Biological degradation +O2

Cl Cl Cl Cl Cl Cl

Fatty acids

PCB PCB

Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl

Uptake

> 50 years

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SLIDE 8

Effect of Activated Carbon

Millward et al, Environ. Sci. Technol. 2005

Conclusion:

  • Reduced uptake of PCB in tissue
  • Reduced bioavailability for tested species

Questions:

  • Reduced bioavailability for bacteria?
  • Effects on dechlorination rates and products?
  • L. plumulosus
  • N. arenaceodentata
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PCBs - Processes in sediment

Resuspension Biological dechlorination Ingestion Biological degradation +O2

Cl Cl Cl Cl Cl Cl

Fatty acids

PCB PCB

Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl

Uptake

? ?

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SLIDE 10

Are PCBs available for bacteria?

Conclusion:

  • Dechlorination of Aroclor 1260 in sediment with GAC

⇒ No effect of GAC based on average chlorine content

Kjellerup et al, Water Res (2014), Apr 1;52C:1-10

4.0 4.5 5.0 5.5 6.0 6.5 7.0 50 100 150 200 250 300 Time (Days) Chlorines per biphenyl

No GAC With GAC

Average chlorine content

GAC added

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  • 10%
  • 5%

0% 5% 10% 15% 20% 25% 30% 35% 40%

C1 C4,10 C7,9 C6 C5,8 C14 C19 C11 C15,17 C16,32 C29,54 C25 C28,31,50 C20,21,33,53 C22,51 C52,73 C43,49,38 C35,104 C44 C41,64,71,72,68 C57,103,40 C67,100 C66,80,93 C90,101 C119,150,112 C136 C151 C124,135,144 106,118,139, 149 C153,132,105,127 C141,179 C176, C130 C138,163,164 C158,186 C187,159,182 C183 C174,181 C177 C156,171,202 C197 C193 C170,190

Congener Mol%

Increase Decrease

Conclusion:

  • With GAC, full dechlorination possible
  • Aerobic microbes can now degrade biphenyl rings

Bacteria With GAC Bacteria Alone

mono/di- chlorinated congeners tri/tetra/penta-chlorinated congeners - STALLS FULL DECHLORINATION

???

GAC without Bacteria Bacteria with no GAC Bacteria with GAC

Are PCBs available for bacteria?

Kjellerup et al, Water Res. 2014

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Different bacterial populations?

Screening of bacterial diversity using DHPLC and primers targeting dechlorinating bacteria (16S rRNA) Conclusion:

  • Dominant dechlorinating phylo-types are the same → Not

responsible for difference in dechlorination

Kjellerup et al, Water Res (2014), Apr 1;52C:1-10

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Biofilm on GAC in sediment

5 µm

Dechlorinating bacteria

Conclusion:

  • Biofilms are present in sediment
  • Natural mode of growth
  • Can we utilize this observation?
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Biofilm on GAC in sediment

5 µm

Dechlorinating bacteria

Conclusion:

  • Biofilms are present in sediment
  • Natural mode of growth
  • Can we utilize this observation?

Dual approach: 1. Adsorption of PCBs on activated carbon 2. Biofilm instead of liquid inoculum for bioaugmentation? Objective: Apply biofilm communities to PCB contaminated sediment as a delivery system to enhance dechlorination

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SLIDE 15

15

Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl

Granular activated carbon Anaerobic dechlorinating bacteria PCBs Previous Bioremediation Approach

Technical Approach - Detail

Biofilm Bioremediation approach

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16

Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl

Technical Approach - Detail

Previous Bioremediation Approach Biofilm Bioremediation approach Granular activated carbon Anaerobic dechlorinating bacteria PCBs

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Direct SYBR Green staining - CLSM

Betsey Pitts, MSU/CBE, 2012

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Anaerobic Biofilm Formation

SYBR Green staining & CLSM

Edwards et al, 2016 (In prep)

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Sediment mesocosms from Grasse River, NY

  • Two types of biofilm inoculum

Dechlorination rate Biofilm enhances the dechlorination rate

Effect on dechlorination?

* *

* Statistical significance <30% - EPA Standard

Edwards et al, 2016 (In prep)

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SLIDE 20

* * * * * * * * *

Dechlorination after 200 days

Increase Decrease

Mono and di-chlorinated congeners - significantly more in the presence of biofilm compared to GAC and liquid inoculum Day 0 Day 200

Effect on dechlorination?

* Statistical significance <30% - EPA Standard

Edwards et al, 2016 (In prep)

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Can the numbers of bacteria explain the difference in activity?

  • Anaerobic DF1 biofilm

The numbers of dechlorinating bacteria are similar over time ⇒ Not responsible for the difference in activity Reason: ⇒ Diversity? ⇒ Mode of growth?

Can the numbers explain?

Edwards et al, 2016 (In prep)

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Looking at the microbial populations in the sediment ↓ What is the effect of Biofilm Augmentation?

  • Approach: Multiplex 16S rRNA gene seq. - Illumina MiSeq

Effect of Biofilms?

Edwards et al, 2016 (In prep)

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Influence of Biofilms?

Edwards et al, 2016 (In prep)

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SLIDE 24

Influence of Biofilms?

Edwards et al, 2016 (In prep)

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Effect of Biofilm Augmentation?

Summa mmary: ry:

  • Enhanced PCB dechlorination
  • Sediment Population analysis:
  • Other Chloroflexi than “usual suspects” are involved

(Dehalococcoides and DF1)

  • 18 groups of bacteria show 2+ fold upregulation

→ Related to contaminated sediment/soil (anaerobic) What hat does does thi his mean? ean? Biofilms impact the overall sediment population, NOT only the PCB dechlorinating population. Mec echani hanism?

Edwards et al, 2016 (In prep)

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Biofilm based delivery system

Activated carbon Biochar Fe covered AC Zeolite

Ongoing research activities: Identification of the mechanism responsible for increased activity of GAC-Biofilm based bioaugmentation

  • Electrical conductivity?
  • Sorption (kinetics)?
  • Surface area/porosity?
  • Other?
  • A. Prieto et al (in prep), 2016
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Biofilm based delivery system

Sand Coconut biochar Peanut Biochar – B. xenovorans LB400

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  • Dechlorinating biofilms can

effectively be cultured under anaerobic conditions

  • Application of anaerobic

biofilms as a delivery vehicle enhances dechlorination of PCBs in sediment

  • Biofilms are robust and can be

maintained in sediment

Summary

→ Good solution for anaerobic bioremediation → Complete mineralization?

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SLIDE 29

Aerobic

Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl

Burkholderia LB400 DF-1

Anaerobic +O2 CO2

Fate of PCBs in Mixed Biofilms

  • A. Prieto et al (in prep), 2016
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Recontamination of sediment from wastewater?

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Outfall 002 Outfall 001 Average 4.25 5.09 STDEV 0.51 0.39

Outfall 002 Outfall 001 Average 4.25 5.09 STDEV 0.51 0.39

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Others involved:

  • Kevin R. Sowers, Ph.D. IMET, UMBC
  • Ms. Betsy Pitts, M.Sc., Center for Biofilm Engineering,

Montana State University

  • Dr. Recep Avci, Ph.D., Image and Chemical Analysis

Laboratory, Montana State University

  • Natasha Andrada & Upal Ghosh, Ph.D., UMD/UMBC

Financial support for Project ER 2135 Students:

Freshta Akbari, Sarah Edwards Chiara Draghi (Graduated) Kirstie Coombs, BS (2017) Raymond Jing, Ph.D. (2019)

  • Dr. Ana Prieto, Post Doc.

Kjellerup Lab

Acknowledgements

Terp Service Day

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Thanks for your attention.

Contact – Please email: bvk@umd.edu