The Need

Propionibacteria are well-known for their various industrial applications including the manufacturing of Swiss cheese, vitamin B12, and propionic acid. However, not much is known about their genetics, and few studies have been conducted utilizing them for metabolic engineering, mostly in vitamin B12 production. To date, no wild-type organism is known to produce n-propanol in sufficient quantities for industrial applications.

The Technology

Researchers at The Ohio State University led by Dr. Shang-Tian Yang have found a method of producing n-propanol using metabolically engineered Propionibacterium, which offers a novel route to produce n-propanol from renewable feedstock, and possibly a new way to boost propionic acid fermentation. The production of n-propanol was limited by NADH availability, but was improved significantly by using glycerol as the carbon source. This method offers the simplicity of single gene overexpression in comparison to overexpressing and knocking out multiple genes in other microorganisms. The improved propanol production was also accompanied by a significant increase in propionic acid production.

Commercial Applications

• Chemical production
  • Polypropylene manufacturing
• Energy
  • Biofuel
• Propionic acid fermentation
  • Plastics, resins, polymers, herbicides, perfume, food preservatives

Benefits/Advantages

• First report on producing n-propanol from any propionibacteria
• Allows redox status and product yield management through control of the carbon source
• Provides a new approach to improve propionic acid fermentation production
• Potential improvement in n-propanol yields with further metabolic and process engineering