# Activity Expression and Property Analysis of Codon-Optimized Polyphenol Oxidase from Camellia sinensis in Pichia pastoris KM71

## TL;DR

This study shows that optimizing the codons of a tea enzyme improves its production and activity in a yeast system, which could help in tea and food production.

## Contribution

Codon optimization significantly increased the activity of tea polyphenol oxidase in Pichia pastoris.

## Key findings

- Codon optimization led to a 42.89-fold increase in enzyme activity (1286.67 U/mL).
- The optimal temperature and pH for the enzyme were 40 °C and 5.5, respectively.

## Abstract

Tea polyphenol oxidase (CsPPO) is a crucial enzyme involved in the production of tea and tea products. However, the recombinant expression of CsPPO in microorganisms is often hindered by challenges such as inclusion body formation and extremely low enzyme activity. In this study, the CsPPO gene (1800 bp) from Camellia sinensis cv. Yihongzao was cloned and 14.5% of its codons were optimized for Pichia pastoris expression. Compared to pre-optimization, codon optimization significantly enhanced CsPPO production in P. pastoris KM71, yielding a 42.89-fold increase in enzyme activity (1286.67 U/mL). The optimal temperature and pH for recombinant CsPPO were determined to be 40 °C and 5.5, respectively. This study demonstrates that codon optimization effectively improves the expression of plant-derived enzymes such as CsPPO in eukaryotic expression systems. Future research should explore the long-term stability of recombinant CsPPO and its potential applications in tea fermentation processes and functional food development.