pha production from organic wastes: the role of vfas and ...€¦ · monitoring and control...

PHA Production from Organic Wastes: The Role of VFAs and Digestate as Nutrient Media

Prof. Sandra [email protected]

21st May 2015, Birmingham, UK

mailto:[email protected]

Hydrogen Energy

Biohydrogen Systems

Advanced Nanomaterials

Bio Energy Systems

Anaerobic Digestion

Waste and Wastewater Treatment

Monitoring and Control

Environmental Analysis

Bioelectrochemical Devices

The

Hydrogen

Centre

Biochemicals and Bioplastics Production

Biogas Upgrading and Utilisation

Life Cycle Analysis

What about GREEN Chemical and

Biopolymer Platforms?

Energy and material fluxesThe Fluxes in Today’s Society

are already Complex

Chemicals from Methane: Acetic Acid

Acetic Acid Production Route:

Price of Acetic Acid

Variable, but can be sold for $500-1300 per metric tonne

Acetic Acid End-uses

Adhesives, coatings, inks, resins, dyes, paints and pharmaceuticals. It can also be further converted into other chemicals e.g. vinyl acetate, acetic anhydride, cellulose acetate, terephthalic acid and polyvinyl chloride

Annual Global Production of Acetic Acid

10.7 million tonnes (34th highest production volume chemical)

CH4 2H2 + CO

CH3OHCH3COOH

Steam Reforming

+ H2O

Methane

Synthesis

Gas

Methanol

Acetic Acid

Methanol Carbonylation

+ CO

CH4Biomethane

Biohydrogen

Acetic Acid

2H2+ CO

CH3COOH CH3OH

Chemicals from Biomethane: Acetic Acid

Products from

anaerobic

fermentations

Chemicals from Methane: UreaUrea Production Route:

CH4 2H2 + CO

NH3(NH2)2CO

Steam

Reforming

+ H2O

Methane Synthesis Gas

AmmoniaUrea

H2 + CO2Water Gas

Shift Reaction

+ H2O

+ N2Haber

Process

+ CO2

Hydrogen and

Carbon Dioxide

End-uses of Urea

91% of urea is used for the production of solid nitrogen-based fertilisers. Non-fertiliser uses include the production of urea-formaldehyde resins, melamine, animal feed and numerous environmental applications

Annual Global Production of Urea

120 million tonnes (18th highest production volume chemical)

Chemicals from Biomethane: Urea

CH4

Biohydrogen

and carbon

dioxide

2H2+ CO

Products from

anaerobic

fermentations

H2+ CO2

Biomethane

NH3Ammonia

(NH2)2CO

Price of Urea

$300-500 per metric tonne

Anaerobic Digestion Process

Rate limiting

Bio

gas

© University of South Wales

Acetate

Propionate

Eubacteria

Methanosaetaceae

Methanobacteriales

Methanomicrobiales

Methanosarcinaceae

Williams et al. 2013



Methanogens and VFA residuals


Propionate

VFA

(m

g /

l)


Propionate & LithotrophicMethanogens

Diversity of Populations in Different InoculaPhylum distribution

(%)*Inoculum A Inoculum B

Methanosaeta 0 2

Methanosarcina 6 0

Actinobacteria 0 8

Firmicutes 55 11

Bacteroidetes 26 20

Planctomycetes 0 0

Proteobacteria 0 7

Spirochaetes 0 2

Synergistetes 1 7

Tenericutes 1 0

Verrucomicrobia 0 1

Chloroflexi 2 8

Unknown gene copies 8 33

Oliveira et al. To be submitted


Integration of Anaerobic Processes & PHA production


~ 1/3 of the initial VS converted to VFAsin a matter of a couple of days and the

rest can be produced in another fermentation

Jobling-Purser et al., submitted

Experiments

Volatile Fatty Acids from Food Wastes


Kumi et al., to be submitted

Volatile Fatty Acids from Badmington Grass



VFA Production from Thermally Hydrolysed Secondary Sludge

Kumi et al., to be submitted

VFAs in Percolate MSW (Full Scale)

Oliveira et al. In preparation

Double solubilisation of organics to be digested instead of composted and available for biorefining products


Near Infrared Spectroscopy In Bioreactor Performance Monitoring

Data Point

3.1

3.3

3.5

3.7

3.91 2 3 4 5 76 8

2.1

2.3

2.5

Volatile Solids

Total Solids

Bicarbonate Alkalinity

1500

2000

2500

3000

3500

4000

-400

-200

0

200

400

600

800

1000

1200

1400

1600

5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77

Volatile Fatty Acidsmg.L-1

mg.L-1

g.L-1

g.L-1

Data Point

3.1

3.3

3.5

3.7

3.91 2 3 4 5 76 8

2.1

2.3

2.5

2.1

2.3

2.5

2.1

2.3

2.5

2.1

2.3

2.5

Volatile Solids

Total Solids

Bicarbonate Alkalinity

1500

2000

2500

3000

3500

4000

-400

-200

0

200

400

600

800

1000

1200

1400

1600

5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77

-400

-200

0

200

400

600

800

1000

1200

1400

1600

5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77

Volatile Fatty Acidsmg.L-1

mg.L-1

g.L-1

g.L-1

Reed et al., 2011


Concentration of VFAs fromSewage Sludges Pretreated Hydrolysates (Before Acidification)

Concentrate:Nearly 20,000mg/l total VFAs, which was the aim for the application

Tao et al., submitted © University of South Wales

Modern human society depends on the use of plastics

light weight, durable and versatile and have been even cheap

Very short life span in many cases

Fossil fuel based plastics impose adverse environmental impacts

non-biodegradable; persisting in the environment for a long time causing severe damage to wildlife

Google images

Bioplastic Categories

Maize and/or potato starch in blend with

polycaprolactones and other biodegradable esters

PHAPHA

Extraction

Biomass from crops Biomass from crops Biomass from crops and wastes

Starch, cellulose Sugars Sugars, oils, VFAs

Modification

Microbialfermentation Microbial

fermentation

Starch and cellulosematerials

Lactic acid

Polyhydroxyalkanoates (PHA)Chemicalpolymerisation

Poly(lactic acid)

ACADEMIC EXPERTISE FOR BUSINESS (A4B)Collaborative Industrial Research Project

SuPERPHA – Systems and Product Engineering Research for Polyhydroalkanoates (PHA)

July 2013 – Dec 2014 (£1.2M)

University of South Wales (lead)

Partners:

Swansea and Bangor Universities

Aber Instruments Ltd.

Axium Process Ltd.

Excelsior Technologies Ltd.

FRE-Energy Ltd.

Kautex-Textron Ltd.

Loowatt

NCHNextek Ltd.Scitech Adhesives systems Ltd.(Supported by BASF)Thames WaterWaitrose Welsh Water



Polyhydroxyalkanoates (PHA) accumulate as intracellular carbon and energy reserve naturally within a variety of gram positive and gram negative bacteria.

General principle for PHA accumulation = Excess carbon + Nutrient deficiency.

PHAs are thermoplastic polyesters with melting point 50-180ºC. UV stable, low permeation of water and good barrier properties

Properties can be tailored to resemble elastic rubber (long side chains) or hard crystalline plastic (short side chains)

Polyhydroxyalkanoates

O

O

O

OO

O

OO

O

O O

O

OO

OPolyhydroxybutyrate

(PHB)

Brittle

PHBcoPHV

Hard/flexible

Medium chain lengthPolyhydroxyalkanoate

(mclPHA)

Thermoplastic Elastomer

Chemical Structures


Cupriavidus necator

Cupriavidus necator, industrialPHA producer, has shown tonaturally produce PHB close to85% of its dry weight.

Gram negative, rod-shaped,flagellate, chemo heterotrophic(DSMZ).

Species generally occurs in soil,known for resistance to variousmetals.

Xu et al., 2010 - TEM images of C. necator in fermentation,(A) 24 h, (B) 62 h, (C) 70 h, and (D) 82 h.


This presentation outlines the investigations related to threemain important factors :

1. Optimal feeding of VFA for maximum PHA production;2. The establishment of a real-time tool for determination of

the optimum polymer harvesting time;3. The utilisation of nutrients from digestates for bacterial

growth and PHA production; and4. Evaluation of the effects of sodium chloride on bacterial

growth and PHA accumulation.

Various control strategies for maximum PHA production


0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 5 10 15 20 25 30 35 40 45 50

PH

A (g

/l)

Time (h)

1% Acetic Acid

2% Acetic Acid

3% Acetic Acid

4% Acetic Acid

5% Acetic Acid

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 10 20 30 40 50 60 70 80

PH

B (

g/L)

Time (h)

1% Butyric Acid

2% Butyric Acid

3% Butyric Acid

4% Butyric Acid

5% Butyric Acid

Batch fermentations with single VFAaddition of 1 – 5 % v/v acetic acid and1 – 5 % v/v butyric acid

When VFA was supplied as a singlefeed, it was found that concentrationshigher than 3% v/v VFA led to substrateinhibition.Only 18% acetic acid and 12% ofbutyric acid was converted into PHA,resulting in less than 65% (w/w) of PHAcontent in the microbial cells.

VFA supplied as a single feed

Kedia et al., 2015


Monitoring Real Time PHA Accumulation

Online capacitance (pF/cm) profile and ex-situ measured PHA yield in medium fed with acetic acid as the carbon source or without excess carbon

source.

0

1

2

3

4

5

0

0.25

0.5

0.75

1

1.25

0 10 20 30 40 50

PH

A (

g/l

)

Cap

acit

ance

(p

F/cm

)

Time (h)

Capacitance- Acetic Acid Capacitance- without excess carbon

PHA (g/l)- Acetic Acid PHA (g/l) - without excess carbon


Online capacitance (pF/cm) profile and ex-situ measured PHA yield in medium fed with butyric acid as the carbon source.

Monitoring Real Time PHA Accumulation


PHA Concentration / Yield from Digestates and NM

In D2, PHA concentration wasincreased by almost 3x whencompared to D1 and NM.

The cells were almost 90%packed with PHA in D2.

0

3

6

9

12

15

0 10 20 30 40 50 60

NM D1 D2

Time (h)

PH

A(g

/l)

PHA Yields and % CDW:

NM - 0.21 g PHA/ g VFA (28 h); 78 % CDWD1 - 0.14 g PHA/ g VFA (48 h); 84% CDWD2 - 0.48 g PHA/ g VFA (43 h); 90% CDW


Effect of NaCl concentration on bacterial growth

0

1

2

3

4

5

6

7

8

0 10 20 30 40 50

3.5 g/l NaCl 6.5 g/l NaCl 9 g/l NaCl

12 g/l NaCl 15 g/l NaCl No salt

Time

CD

W (

g/l)

At 24 h, max CDW was demonstratedby 9 g/l NaCl concentration9 g/l NaCl = CDW 6.8 g/l 3.5 g/l NaCl = CDW 6 g/l 6.5 g/l NaCl = CDW 6.1 g/l Control = CDW 6.4 g/l

For fermentations with NaClconcentrations of 12 g/l and 15 g/l theCDW was 69 - 70% lower than comparedto the control at 24 h, indicating aninhibitory effect at higher saltconcentrations demonstrated by thelower cell growth of C. necator cells.

CDW profile for NaCl concentration fermentations and control

AD integration with Biopolymers

• Digestate Nutrient Management

• Biopolymer PHA digests well – high CH4 yield –contributing to increasing C:N ratio in digesters and increase in digestate quality


Biocomposite Centre

Recycling Bioplastics

Through AD Processes


Anaerobic Biodegradability of Polymers

-100

0

100

200

300

400

500

600

0 10 20 30 40 50 60 70

Met

han

eyi

eld

ml C

H4

/ g

VS

add

ed

Days



The sole responsibility for the content of this document lies with the authors. It does not necessarily reflect the funders opinion. Neither the authors or the funders are responsible for any use that may be made of the information contained therein.

AcknowledgmentsDr. Tim Patterson, Dr. Gopal Kedia, Dr. Pearl Passanha, Phil Kumi, Ben Joblin-Purser, Dr.Des Devlin, Dr. James Reed, Dr. Julie Williams, Dr. Gregg Williams, Dr. Christian Laycock,Prof. Richard Dinsdale, Prof. Alan Guwy, Dr. Robert Lovitt and team (SwanseaUniversity) and Dr. Robert Elias and team (Bangor University)
http://www.insource-energy.co.uk/http://www.insource-energy.co.uk/https://dwrcymru-welshwater.bravosolution.co.uk/https://dwrcymru-welshwater.bravosolution.co.uk/

pha production from organic wastes: the role of vfas and ...€¦ · monitoring and control...

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