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High-yield ‘one-pot’ biosynthesis of raspberry ketone, a high-value fine chemical

Moore, Simon J., Tosi, Tommaso, Bell, David, Hleba, Yonek B., Polizzi, Karen M., Freemont, Paul S. (2021) High-yield ‘one-pot’ biosynthesis of raspberry ketone, a high-value fine chemical. Synthetic Biology, 6 (1). Article Number ysab021. E-ISSN 2397-7000. (doi:10.1093/synbio/ysab021) (KAR id:89561)


Cell-free extract and purified enzyme-based systems provide an attractive solution to study biosynthetic strategies towards a range of chemicals. 4-(4-hydroxyphenyl)-butan-2-one, also known as raspberry ketone, is the major fragrance component of raspberry fruit and is used as a natural additive in the food and sports industry. Current industrial processing of the natural form of raspberry ketone involves chemical extraction with a yield of ~1-4 mg kg-1 of fruit. Due to toxicity, microbial production provides only low yields of up to 5-100 mg L-1. Herein, we report an efficient cell-free strategy to probe a synthetic enzyme pathway that converts either L-tyrosine or the precursor, 4-(4-hydroxyphenyl)-buten-2-one (HBA), into raspberry ketone at up to 100% conversion. As part of this strategy, it is essential to recycle inexpensive cofactors. Specifically, the final enzyme step in the pathway is catalysed by raspberry ketone/zingerone synthase (RZS1), an NADPH-dependent double bond reductase. To relax cofactor specificity towards NADH, the preferred cofactor for cell-free biosynthesis, we identify a variant (G191D) with strong activity with NADH. We implement the RZS1 G191D variant within a ‘one-pot’ cell-free reaction to produce raspberry ketone at high-yield (61 mg L-1), which provides an alternative route to traditional microbial production. In conclusion, our cell-free strategy complements the growing interest in engineering synthetic enzyme cascades towards industrially relevant value-added chemicals.

Item Type: Article
DOI/Identification number: 10.1093/synbio/ysab021
Uncontrolled keywords: synthetic biology; fine chemical; raspberry ketone; polyketides; cell-free
Subjects: Q Science > QD Chemistry > QD431 Organic Chemistry- Biochemistry- Proteins, peptides, amino acids
Q Science > QH Natural history > QH301 Biology
Q Science > QR Microbiology
Divisions: Divisions > Division of Natural Sciences > Biosciences
Depositing User: Simon Moore
Date Deposited: 02 Aug 2021 07:56 UTC
Last Modified: 09 Jan 2024 12:33 UTC
Resource URI: (The current URI for this page, for reference purposes)

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