# Strategies for Metabolic Engineering of Escherichia coli for β-Carotene Biosynthesis

## TL;DR

This paper reviews strategies to engineer Escherichia coli for efficient β-carotene production, a valuable compound used in food, pharmaceuticals, and cosmetics.

## Contribution

The paper systematically summarizes metabolic engineering strategies for β-carotene biosynthesis in E. coli, emphasizing sustainable production.

## Key findings

- E. coli is a suitable host for β-carotene production due to its rapid growth and genetic tractability.
- Strategies include optimizing the MEP pathway, introducing the MVA pathway, and modifying central carbon metabolism.
- Efficient β-carotene production supports the sustainable synthesis of carotenoids and apocarotenoids.

## Abstract

β-Carotene has extensive applications in the food, pharmaceutical, and cosmetics industries. Traditional chemical synthesis methods face challenges such as byproduct residues and high costs, whereas natural extraction is constrained by low yields and complex processes. Recent advancements in synthetic biology and metabolic engineering have paved the way for the heterologous biosynthesis of β-carotene in microorganisms. Owing to its rapid growth, convenience of genetic manipulation, and suitability for producing apocarotenoids, Escherichia coli is an ideal host for the production of β-carotene and its derivatives, as exemplified by the record production of multiple apocarotenoids in engineered E. coli strains. Here, we summarize the metabolic engineering strategies employed to produce β-carotene in E. coli, including manipulation of the endogenous MEP pathway, introduction of the hybrid MVA pathway, modulation of central carbon metabolism, modification of the cell membrane, and fermentation process optimization. As β-carotene acts as a biosynthetic hub for many carotenoids and apocarotenoids, we also highlighted the importance of efficient β-carotene production for the sustainable preparation of these compounds. This review aims to provide theoretical insights for designing talented β-carotene producers and laying the foundation for the sustainable manufacturing of valuable carotenoids and apocarotenoids.