Acetogenic Bacteria.pptx

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 coskatii .

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 .