Pentose fermentation
By: Ben, Cara, Jeremy, and Songmi
Pentose fermentation
● Microorganisms dissolve pentose using their enzyme
● Production of bio-ethanol
Why is pentose fermentation important?
-A shortage of petroleum/natural gases have sparked more interest in using
renewable biomass resources for fuel.
-Ethanol produced from sugar fermentation
-Pentose= significant portion of total fermentable sugars
Current Research:
● Alternative fuel sources
● Microorganisms capable of making biofuels (Ethanol)
Pentose
● General term for 5 carbon sugars
● Monosaccharide aka “Carbohydrate”
● Used to make various ethanols
● Formula C H O
5
10
5
What is metabolic engineering?
● Using a cells function for output
● Pin-point parts of the cell that constrain production of
products
● Optimizing cells conditions to output a desired
substance
● Desired substance: Various bio-ethanols
Why bio-fuels?
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Cost efficient
Renewable
Eco-friendly
Economical
Microorganism capable of producing bioethanol
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Various yeast strains
S. cerevisiae
Escherichia coli
Klebsiella oxytoca
+ dozens of other strains
Escherichia coli
● Mass production of ethanol is possible
● Ability to metabolize different pentose
compounds natively
● Very high experimental yield
● Different strains with different yields
PhenotypeTCS083/pLOI297
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Very effective at synthesizing ethanol
Can utilize xylose and glucose
Not found in the wild
Currently patented (US20100255553)
91% ethanol yield from pentose sugars
Strain with highest yield
S. Cerevisiae
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The most well established yeast for ethanolic fermentation
○ Yeast/Bacteria:
■ superior resistance to hydrolysate inhibitors
■ better growth in low pH
■ less nutritional requirements
It does not naturally metabolize xylose (pentose sugars)
○ Introduce metabolic pathways/sugar transport proteins
Research:
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Metabolically engineered to enhance ethanol production:
○ Replacing native P. Stipitis with mutation (xylose reductase) improved
fermentative capabilities
Conclusion/ Future Research
Challenges:
-simultaneous co-fermentation of hexose/pentose sugars
-Increase byproduct formation
Future:
-minimize the co-fermentation of sugars and byproduct formation
-S. Cerevisiae: development of a strain engineered to express pentose
metabolising proteins from fungi living on decaying plant material
-Increase inhibitor tolerance
Sources
-http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3056094/
Fernandes, Sara, and Patrick Murray. "Metabolic Engineering for Improved
Microbial Pentose Fermentation." Bioengineered Bugs. Landes Bioscience, n.d.
Web. 06 May 2015.
-http://cta.ornl.gov/bedb/biofuels/ethanol/Ethanol_Overview.shtml
"Biofuels, Ethanol Overview." Biofuels, Ethanol Overview. N.p., n.d. Web. 06
May 2015.
- https://www.ideals.illinois.edu/bitstream/handle/2142/34403/koita_khushnuma.pdf?sequence=1
“KOITA, KHUSHNUMA. "OPTIMIZING PENTOSE SUGAR UTILIZATION IN ESCHERICHIA COLI
FOR THE PRODUCTION OF BIOFUELS." 2012. Web. 7 May 2015.”
Sources cont.
- http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2446564/
“Trinh, Cong, Pornkamol Unrean, and Friedrich Srienc. "Minimal Escherichia Coli Cell for the Most
Efficient Production of Ethanol from Hexoses and Pentoses." Applied and Environmental Microbiology.
American Society for Microbiology (ASM). Web. 7 May 2015.”
- http://www.google.com/patents/US8623622
"Patent US8623622 - Genetically-engineered Ethanol-producing Bacteria and Methods of Using."
Google Books. Web. 7 May 2015.
- http://www.journalagent.com/tjb/pdfs/TJB_40_1_74_80.pdf
“Deniz, Irem, Esra Imamoglu, and Fazilet Sukan. "Evaluation of Scale-up Parameters of Bioethanol
Production from Escherichia Coli KO11." 24 Jan. 2015. Web. 7 May 2015.”