Biovanillin production from ferulic acid by employing Pseudomonas fluorescens BF13-1p

Vanillin (4-hydroxy-3-methoxy-benzaldehyde) is one of the most important flavouring compounds used in foods, beverages, perfumes and pharmaceuticals. In this work we evaluated the possibility of producing vanillin by bioconversion of ferulic acid employing a genetically modified Pseudomonas fluorescens strain (BF13-1p), lacking the vanillin dehydrogenase gene. The strain was grown on LB medium prepared with industrial grade components. The biomass was then collected and suspended in a bioconversion buffer solution containing food-grade ferulic acid as the substrate for biovanillin production. Both the growing-phase and the bioconversion stage of the process were optimized in terms of pH, temperature and ferulic acid concentration. The possibility of reusing exhausted cells was also investigated. Maximum biovanillin accumulation was 1.5 g/L with fresh biomass and 1.0 g/L with reused biomass. These results are interesting in the perspective of producing biovanillin with non-actinomycetes strains.