New Insights Into Curcumin Behavior After Its Biosynthesis in Engineered Escherichia coli Through Spectroscopic and...

Area of Science:

• Biotechnology
• Microbial biosynthesis
• Natural product chemistry

Background:

• Curcumin, a compound with anti-inflammatory, cholesterol-lowering, antidiabetic, and antioxidant properties, can be biosynthesized in microbial hosts.
• The native source of curcumin is Curcuma longa roots.

Purpose of the Study:

• To investigate the behavior and localization of biosynthesized curcumin within and outside engineered microbial cells.
• To identify factors limiting microbial curcumin production and inform strategies for enhancement.

Main Methods:

• Engineered Escherichia coli BL21(DE3) for curcumin biosynthesis from ferulic acid.
• Advanced imaging techniques including Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Second Harmonic Scattering (SHS) spectroscopy, and Two-Photon Fluorescence (TPF) imaging.
• Surface binding analysis using SHS spectroscopy to determine adsorption free energy (ΔG).

Main Results:

• Curcumin was successfully biosynthesized in E. coli.
• SHS spectroscopy revealed curcumin binding to the E. coli cell surface with an adsorption free energy of -14.0 kcal/mol.
• Electron microscopy and imaging methods showed curcumin aggregates forming within cells, on the cell surface, and in the surrounding media.

Conclusions:

• Curcumin biosynthesis in E. coli results in significant intracellular aggregation, which may impede cellular function and production.
• Understanding curcumin's intracellular and extracellular localization, transport, and aggregation is critical for optimizing microbial production pathways.
• Strategies to manage curcumin aggregation are necessary for efficient industrial-scale biosynthesis.