Employing Nanotechnology to Enhance Ethanol Production in Two Synechococcus elongatus Strains

Area of Science:

• Synthetic Biology
• Metabolic Engineering
• Biotechnology

Background:

• Cyanobacteria are promising photosynthetic cell factories but suffer from low product yields.
• Industrial exploitation of cyanobacteria is hindered by inefficient bioproduction.

Purpose of the Study:

• To enhance product titres in cyanobacteria using bacterial microcompartment technology.
• To investigate the efficacy of enzyme targeting via encapsulation peptides (EPs) for improved ethanol biosynthesis.

Main Methods:

• Enzyme-EP fusions were created and tested for targeting to nanofilaments or as soluble aggregates.
• Two Synechococcus elongatus strains (PCC 7942 and UTEX 2973) were used to evaluate the impact of growth rate.
• Ethanol production and enzyme levels were quantified and compared to unmodified enzyme production.

Main Results:

• Encapsulation peptides (EPs) increased enzyme levels and ethanol titres by up to 84-fold.
• The fastest-growing strain (Synechococcus elongatus UTEX 2973) achieved the highest overall titres due to increased cell density.
• The optimal strategy, enzyme-EP fusion without nanofilaments, yielded 1.31 g L⁻¹ of ethanol in 6 days.

Conclusions:

• Nanotechnology-based strategies, particularly enzyme-EP fusions, significantly improve cyanobacterial bioproduction.
• This approach offers a viable pathway to overcome yield limitations in photosynthetic cell factories.
• The findings provide a blueprint for engineering cyanobacteria for enhanced industrial bioprocesses.