Transcript 03.Selected Products.Acetate.web

Selected Products of
Bioprocessing
digging a bit deeper
Acetic Acid
• Ancient process
• Romans and Greeks –
beverage
• no big deal, they just left
their wine vat open to the
air
Acetic acid bacteria
• Gluconobacter oxydans: ethanol to acetic
acid via oxidation
• Acetobacter: ethanol to acetic acid to CO2
and H2O
Bit of biochemistry
2H+
Respiration
ATP + H2O
2H+
CH3CH2OH
ethanol
CH3CHO
CH3CH(OH)2
CH3COOH
acetaldehyde
acetaldehyde
hydrate
acetic acid
ethanol
dehydrogenase
hydration
acetaldehyde
dehydrogenase
Process details
• aerobic process
• at 12% acetic acid, 30% cells
dead in 10-20 seconds after
air cut off
Bioreactor
ethanol feed
29oC
beechwood chips
35oC
huff and puff
60 m3 tank
cooling and recycle