# Review in Structure–Activity Relationships, Synthetic Regulation, and Applications of Mono/Di-Rhamnolipids

## TL;DR

This review explores how different types of rhamnolipids can be tailored for specific uses in energy, environment, and health.

## Contribution

The paper provides a systematic review of structure-function relationships and targeted synthesis methods for mono- and di-rhamnolipids.

## Key findings

- Mono- and di-rhamnolipids have distinct physicochemical and biological properties.
- Natural rhamnolipid mixtures limit high-value applications due to compositional variability.
- Tailor-made synthesis approaches aim to control the mono-/di-rhamnolipid ratio for specific uses.

## Abstract

Rhamnolipids (RLs) are natural biosurfactants produced by microbial fermentation. They exhibit excellent surface activity, environmental compatibility, and versatile biological activities, with broad application potential in energy development, environmental remediation, personal care, and biomedicine. In recent years, RLs have garnered significant attention due to the structural divergence between mono-rhamnolipids (mono-RLs) and di-rhamnolipids (di-RLs). Their distinct physicochemical and biological properties necessitate structure-function-guided “tailor-made” synthesis. Notably, the compositional fluctuation of naturally occurring RL mixtures constrains their high-value utilization. This review systematically summarizes the structure–function relationships, microbial biosynthetic pathways, and regulatory approaches of mono-RLs and di-RLs, with a core focus on the targeted production of RLs with specific mono-/di-RL ratios. The review also highlights the application-specific suitability of the two RL congeners. It aims to provide a theoretical foundation and technical reference for the precision manufacturing and commercialization of RLs in energy, environment, health, and other related fields.