Bioproduction of raspberry ketone using <i>Phyllostachys</i> bamboo cells expressing raspberry ketone biosynthetic genes

Bioproduction of high-value natural compounds in cultured plant cells represents a favorable strategy compatible with the framework of green sustainable chemistry. Raspberry ketone, a phenylpropanoid-derived compound utilized as a food additive and cosmetics constituent, is a distinctive aromatic component that is accumulated in the ripe fruit of raspberry (<i>Rubus idaeus</i>). Its natural abundance is extremely limited. Consequently, it is imperative to develop methodologies for efficient bioproduction of raspberry ketone. In the present study, we examined the effect of expressing the raspberry ketone biosynthetic genes <i>RpBAS</i> and <i>RiRZS1</i> in bamboo (<i>Phyllostachys nigra</i>) cells, which had been demonstrated previously to be an appropriate host for production of phenylpropanoid-derived compounds, on the bioconversion of precursor compounds into raspberry ketone. The maximal production yield of raspberry ketone, primarily accumulated in the glycosylated form, reached 293 µg g^-1 fresh weight when the <i>RpBAS</i>-<i>RiRZS1</i>-transgenic bamboo cells were cultured in medium supplemented with 4-hydroxybenzalacetone, the immediate precursor of raspberry ketone. These findings underscore the potential utility of bamboo cells for the bioproduction of raspberry ketone from accessible precursors.