The purpose of this study is to understand better Acetogens, unique attributes, Mechanism of specific pathways and their roles in industrial application.

1. ACETOGENIC BACTERIA
By
Okechukwu Francis, Ph.D scholar UPES

2. WHAT ARE ACETOGENS?
These are specialised groups of
obligate and anerobic bacterial
species that are capable of producing
acetate from single carbon substrates
like Cos, formate, methyl group and
CO in a process called “Acetogenesis”
Examples of these bacteria includes
Clostridum asceticum, Clostridium
autoethanogenum, Clostridium
carboxidivorans and Clostridium

3. SEM PICTURE OF CLOSTRIDIUM
CARBOXIDIVORANS GROWN ON CARBON
MONOXIDE SOURCE; HTTP://SURL.LI/COPEU

4. AN IMPORTANT FEATURE OF ACETOGENIC
BACTERIA.
 Acetogens are characterized by a unique pathway,
the Wood–Ljungdahl pathway of carbon dioxide
reduction with the acetyl-CoA synthase as the key
enzyme.
 This pathway also allows chemolithoautotrophic
growth on hydrogen and carbon dioxide and it is the
only pathway known that combines carbon dioxide
fixation with adenosine triphosphate (ATP)
synthesis. Thus, it is considered the first
biochemical pathway on earth.
 ATP is synthesized by a chemiosmotic mechanism
with Na+ or H+ as coupling ion, depending on the
organism.

5. WHY HAVE ACETOGENIC BACTERIA BEEN
OF GREAT INTEREST LATELY?
With over 40Giga tones of carbon
emission have contributed greatly to
global warming. One way to reduce
this process is the use of acetogenic
bateria to produce other gas eg CO to
produce acetate which can be used as
an energy Sources hence saving the
planet (Earth).

6. SOME ACETOGENIC BACTERIA WOULD
PRODUCE ACETATE FROM HARMFUL CO2.
(SOURCE: HTTP://SURL.LI/COPFY)

7. CO DEHYDROGENASE (CODH) IS THE MOST
ENZYME OF THE ACETOGENIC PROCESS.
(SOURCE: HARVARD HOLM RESEARCH GROUP)

8. FEATURES OF ACETOGENASE
 it exists in a complex between CO dehydrogenase
and AcetylcoA synthase.
 Bacteria has the same complex but differently
set/arranged to maximize efficiency.

9. THE CAPABILITY OF ACETOGENS TO UTILIZE
A WIDE RANGE OF SUBSTRATES INCLUDING
INDUSTRIAL WASTE GAS, METHANOL,
FORMATE AND CO HAS LED TO A
TREMENDOUS INTEREST OVER THE LAST
DECADE TO USE THEM AS INDUSTRIAL
PLATFORM ORGANISMS TO PRODUCE THESE
VALUABLE CHEMICAL COMPOUNDS.

10. INDUSTRIAL APPLICATION FLOWCHART UTILIZING
ACETOGENS. (SOURCE: HTTP://SURL.LI/COPFF

11. GENETIC MODIFICATION BENEFIT;
 Genetic scale models (GSM) like Gene Knockout
mechanism amongst others have been used to
achieve various milestones in improved acetogens
such as;
 Improve substrate production
 Reduce metabolic pathways for optimization.
 Reduce effect of toxic CO gas on the acetogens.

12. CONCLUSION
However, it is important to not that;
Lithoautotrophic growth on hydrogen and
carbon dioxide leads to acetate
production coupled to ATP synthesis by a
chemiosmotic mechanism which makes
these organisms the prime candidates for
biotechnological applications.