Basidiomycota strains as whole-cell biocatalysts for the synthesis of high-value natural benzaldehydes

Abstract

Substituted benzaldehydes are the most commonly used natural-occurring flavours in the world. The consumer’s preference for ‘natural or organic’ aromas has increased the request for flavours possessing the ‘natural’ status. The resulting shortage of aromatic aldehydes of extractive origin, such as vanillin, veratraldehyde and piperonal, can be offset by developing a new biotechnological synthesis method. Here, we report a study on the microbiological reduction of five natural benzoic acid derivatives, namely p-anisic, vanillic, veratric, piperonylic and eudesmic acids, to produce the corresponding fragrant aldehydes. We found that different Basidiomycota strains can efficiently perform this transformation, with good chemical selectivity and tolerance to the toxicity of substrates and products. Besides confirming the carboxylic acid reductase activity of the already studied fungi Pycnoporus cinnabarinus, we discovered that other species such as Pleurotus eryngii, Pleurotus sapidus and Laetiporus sulphureus as well as the non-ligninolytic fungi Lepista nuda are valuable microorganisms for the synthesis of anisaldehyde, vanillin, veratraldehyde, piperonal and 3,4,5-trimethoxybenzaldehyde from the corresponding acids. According to our findings, we propose a reliable process for the preparation of the above-mentioned aldehydes, in natural form. Key points • Fragrant benzaldehydes were obtained by biotransformation. • Basidiomycota strains reduced substituted benzoic acid to the corresponding aldehydes. • Anisaldehyde, vanillin, veratraldehyde, piperonal and 3,4,5-trimethoxybenzaldehyde were prepared in natural form. Graphical Abstract

Engineering a Carotenoid Cleavage Oxygenase for Coenzyme-Free Synthesis of Vanillin from Ferulic Acid

“…Overexpressing isoeugenol monooxygenase derived from Pseudomonas nitroreducens Jin1 in recombinant Escherichia coli and isolating it in situ with the aid of magnetic chitosan membranes resulted in a 38.3 g/L accumulation of vanillin Aspergillus niger transforms ferulic acid into vanillic acid, and vanillic acid is reduced to vanillin by Pycnoporus cinnabarinus . Biocatalysis using whole microbial cells has become an essential tool for synthesizing fragrances on a large scale.…”

“…10 Aspergillus niger transforms ferulic acid into vanillic acid, and vanillic acid is reduced to vanillin by Pycnoporus cinnabarinus. 11 Biocatalysis using whole microbial cells has become an essential tool for synthesizing fragrances on a large scale.…”