A method to generate microorganisms showing high-yield synthesis of 6-hydroxynicotinic acid (6-HNA, a precursor of pharmaceuticals, agrochemicals and feed) based on genetic engineering

Background

The production of modern insecticides (e.g. imadacloprid-related), some feed additives and pharmaceuticals (e.g. compounds used for treatment of congestive heart failure, an antilipolytic drug) involves 6-hydroxynicotinic acid (6-HNA).

Since chemical synthesis of 6-HNA is inefficient and expensive due to the formation of by-products, most industrial processes are based on fermentation with bacteria naturally synthesizing 6-HNA. Nevertheless, these bacteria strains also degrade 6-HNA and thus a high concentration of nicotinic acid (the 6-HNA precursor) is added to inhibit this degradation. Besides requiring additional precursor to act as an inhibitor (i.e. not to productive pathways), specific continuous control to ensure a concentration higher than 1% nicotinic acid must be implemented. On the other hand residual 6-HNA degradation is always present even at these concentrations.

Technology

Our approach is based upon a genetically transformed microorganism capable of synthesizing 6-HNA but unable to degrade it. This is achieved by two alternative ways:1) transferring the two bacterial genes for 6-HNA synthesis to a microorganism that is not naturally capable of this synthesis.2) disrupting the expression of the gene involved in 6-HNA degradation in a microorganism that is naturally capable of synthesizing 6-HNA.

This novel approach has been applied to different Pseudomonas strains. A 98-99% yield was consistently reached in all cases.

Main features and advantages

• Higher production yield (close to 100%).
• Lower costs (no need for additional substrate aimed at unproductive effects).
• Easier control (degradation of 6-HNA does not need to be continuously inhibited, since no degrading enzyme is present).
•  There is no poisoning by accumulation of by-products produced by degradation of 6-HNA.
• Straightforward adaptability to current industrial processes and equipments.

Spanish and PCT (“International”) applications filed.

License agreement + Technical support