PHA Production from Organic Wastes: The Role of VFAs and Digestate as Nutrient Media Prof. Sandra Esteves [email protected] 21st May 2015, Birmingham, UK
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
© University of South Wales
Williams et al. 2013
Methanogens and VFA residuals
© University of South Wales
Propionate
VFA
(m
g /
l)
Williams et al. 2013
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
© University of South Wales
Integration of Anaerobic Processes & PHA production
© University of South Wales
~ 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
© University of South Wales
Kumi et al., to be submitted
Volatile Fatty Acids from Badmington Grass
© University of South Wales
© University of South Wales
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
© University of South Wales
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
© University of South Wales
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
© University of South Wales
© University of South Wales
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
© University of South Wales
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.
© University of South Wales
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
© University of South Wales
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
© University of South Wales
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
© University of South Wales
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
© University of South Wales
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
© University of South Wales
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
© University of South Wales
Biocomposite Centre
Recycling Bioplastics
Through AD Processes
© University of South Wales
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
© University of South Wales
© University of South Wales
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/