White rot fungi secrete many oxidizing enzymes that are responsible for both the breakdown of cellulose and the lignin of the wood. Among the secreted enzymes, aryl alcohol oxidases (AAOs) are of interest for biotechnological applications such as the production of bio-based precursors for plastics, bioactive compounds, and aromas and fragrances.
The heterologous expression of the aryl alcohol oxidase 2 (PeAAO2) from Pleurotus eryngii in Pichia pastoris with the highest yield of 315 mg / L described so far was achieved by Nina Jankowski.
The enzyme remained stable in a wide pH range and had high thermal stability. The substrate screening with 41 compounds showed that PeAAO2, in addition to typical AAO substrates, also converted some compounds that were not yet known as substrates for AAOs. Among these, cumic alcohol and piperonyl alcohol were oxidized to cumic aldehyde and piperonal with high catalytic activity. While the fragrance and flavoring compound piperonal is also used as a starting material for agrochemical and pharmaceutical building blocks, various positive effects on health have been attributed to cuminaldehyde. PeAAO2 is thus a promising biocatalyst for biotechnological applications.
Jankowski N, Koschorreck K, Urlacher VB, 2020, High-level expression of aryl-alcohol oxidase 2 from Pleurotus eryngii in Pichia pastoris for production of fragrances and bioactive precursors, Applied Microbiology and Biotechnology, in press, https://doi.org/10.1007/s00253-020-10878-4