Efficient production of 6-hydroxynicotinic acid by newly isolated Pseudomonas poae

Background Nicotinic acid dehydrogenase possesses the capability to convert nicotinic acid into 6-hydroxynicotinic acid, a compound of significant research value as a pharmaceutical intermediate. The extraction of nicotinic acid dehydrogenase is primarily performed by strains. However, the enzyme activity of the strains reported currently is relatively low, and their potential to catalyze the production of 6-hydroxynicotinic acid is insufficient to meet industrial requirements. Results Due to the revealing properties of 6-hydroxynicotinic acid, this study proposes a technique for calculating the luminescence intensity of colonies, which is based on a fluorescence spectrometer. The developed method establishes a reliable linear relationship (88.2%) between the luminescence intensity and enzyme activity. Consequently, it has been employed to screen strains that produce nicotinate dehydrogenase. This screening approach allows for the evaluation of about 500 enzyme-producing strains daily, presenting an efficient strategy for screening. Conclusions Through this approach, a novel high enzyme activity strain producing nicotinic acid dehydrogenase, Pseudomonas poae have been obtained, which designated as HD530. After process optimization, it was utilized to produce 6-hydroxynicotinic acid, achieving a high yield of 155.45 g/L within 72 h, meeting the requirements for industrial production. The effectiveness and potential of this technique lie in its application for strain screening and improvement.