Microbial Production of 1,3-Propanediol, Market evaluation and metabolic pathway

1. Microbial Production of 1,3-Propanediol
Margarida Rodrigues

2. 1,3-PD Market Demand
Poly(trimethylene terephthalate) synthesis
Better stretch recovery
Better durability
Better stain resistance
However chemical synthesis of 1,3-PD is derived which is derived from petroleum feedstock
High Pressures High Temperatures Expensive Catalysts Toxic intermediates
Small-volume chemical Commodity chemical
2013 20221,3-PD
140.5 Kg Tons Market Demand 200 Kg Tons

3. Biodiesel and 1,3-PD Microbial Production
Biodiesel industry
For 10 tons of
biodiesel produced
1 ton of waste
glycerol is
accumulated
Different
microorganisms
can ferment
glycerol to 1,3-
propanediol ;
Bacteria from the
genera:
Klebsiella
Clostridia
Citrobacter
Enterobacter
Lactobacilli
Klebsiella pneumoniae
Citrobacter freudii
Clostridium butyricum
Figure 1. The change in the market price of glycerol in the US and
Europe from 1995 to 20101.
[1] Ciriminna, R. et al. , Understanding the Glycerol Market, European Journal of Lipid Science and Technology (2014)

4. 1,3-PD Metabolic Pathway
Reductive Via
Uses coenzyme B12 as
cofactor
During dehydration
coenzyme B12 is
irreversibly damaged
Inativation of GDHt
Mutant GDHt
by site-direct
mutagenesis
(e.g.) K. pneumoniae
reactivates GDHt with the
exchange of the modified
coenzyme for an intact one
in the presence of ATP and
Mg2+

5. Fermentation Conditions
High amount of glycerolBatch fermentation Anaerobic conditions
Fermentation Conditions [Gly]i
(g/L)
[1,3-PD]
(g/L)
1,3-PD
molar yield
Batch pH=8
t=8h
T=40ºC
20 12,2 0,75
Fed-Batch pH=8
t=48h
T=40ºC
66,4 38,1 0,70

6. Fermentation Strategies
Two-stage Fermentation
Case study with Clostridium butyricum2 :
D1 > D2
[X]1 > [X]2
Q
(ml h1)
D1
(h-1)
D2
(h-1)
X1
(g l-1)
X2
(g l-1)
PD1
(g l-1)
PD2
(g l-1)
92 0.18 0.07 1.8 1.6 29.0 43.3
150 0.30 0.12 1.0 0.7 24.0 41.5
[2] Papanikolaou, S. , et al. Journal of Biotechnology 77 (2000) 191–208
Co-fermentation
Glucose+ Glycerol
mixture Glucose is used to produce
energy
Glycerol is used mainly in
the utilization of the
reducing power
Engineered strains can co-ferment this products
like E.coli and Lactobacillus reuteri ;

7. Downstream processing
Recovery and purification of the 1,3-PD .
Expensive process (50-70% of total process cost)
1,3-PD properties
• Highly hydrophilic
• High boiling point
Complexity of fermentation broth
1) Pretratment and solid-liquid separation.
Objective
Drawbacks
2) Primary Recovery.
3) Final Purification.
Three main steps:
1)
2)
3)

8. Pretreatment
Objective: Remove the microbial cells and soluble protein from fermentation broth.
Pretreatment:
Adjusting pH: add base into the fermentation broth to raise the pH to a suiteble level before distillation.
Solid-Liquid separation:
Flocculation Membrane filtration Centrifugation
1) Pretratment and solid-liquid separation

9. Primary Recovery
Objective: Remove of impurities and primary separation 1,3-PD .
Methods Application Disadvantages
Evaporation
Distillation
Remove water from the fermentation broth.
purification of 1,3-PD .
Large amount of energy consumption.
Desalination and deproteinization are
required before evaporation.
Reactive
extraction
Three key steps:reaction,extraction and hydrolysis. Remove proteins,ethanol and salts are
required before reaction.
Ion exchange
chromatography
Combined with strongly acidic cationic and weakly basic anionic
resins used to desalite in the ferm. Broth.
A cation exchange resin is used for recovery of 1,3-PD .
High consume of energy.
Regenerate frequently the chromatographic
matrix.
2) Primary Recovery

10. Final Purification
Objective: Refining the purity of 1,3-PD.
Methods:
Vacuum distillation
3) Final Purification
Preparative liquid chromatography

11. Market Overview and Conclusion
Bio-based 1,3-PD produces 56% less greenhouse gas emissions and consumes 42% less nonrenewable energy than petroleum-based.