# Honeysuckle as a Bio-Enhancer in Monascus purpureus Fermentation: Synergistic Improvement of Monacolin K Yield and Flavor Complexity

## TL;DR

Adding honeysuckle to Monascus purpureus fermentation boosts monacolin K production and improves flavor, making the product more valuable.

## Contribution

This study introduces honeysuckle co-fermentation as a novel method to enhance both bioactive compounds and flavor in Monascus products.

## Key findings

- Adding 0.8 g/L honeysuckle powder increased monacolin K yield by 1.54-fold.
- Co-fermentation upregulated nine genes in the monacolin K biosynthetic cluster.
- Flavor compounds shifted toward more desirable notes with reduced aldehydes.

## Abstract

Recently, co-fermentation of functional medicinal plants with fungi has emerged as a promising strategy to enhance the overall quality of fermented foods. Monascus fermentation products have long been confronted with bottlenecks in both functionality and palatability, such as low monacolin K (MK) yield and poor flavor. Therefore, this study investigated the effects of co-fermenting Monascus purpureus with honeysuckle (Lonicera japonica Thunb.) on the bioactive metabolites and volatile flavor compounds of the fermented product. Through single-factor optimization, the addition of 0.8 g/L honeysuckle powder was identified as optimal, resulting in a 1.54-fold increase in MK yield compared to the control. Additionally, nine key genes were upregulated in the MK biosynthetic cluster (mokA–mokI). Co-fermentation also significantly increased the total flavonoid and polyphenol contents by 3.93-and 2.01-fold, respectively, and enhanced in vitro antioxidant activity. Gas chromatography-mass spectrometry analysis revealed that ketones, esters, and alcohols were the dominant volatile compounds. Orthogonal partial least squares-discriminant analysis identified 11 differential volatile compounds (variable importance in projection > 1), indicating a substantial shift in the flavor profile toward more desirable notes, with a reduction in undesirable aldehydes. These findings demonstrate that honeysuckle co-fermentation enhances the biofunctional properties of M. purpureus fermentation products and improves their sensory appeal, providing a viable bioprocessing strategy for developing high-value Monascus-based functional foods or ingredients.