Multidimensional optimization for accelerating light-powered biocatalysis in Rhodopseudomonas palustris

Area of Science:

• Biotechnology
• Synthetic Biology
• Microbial Catalysis

Background:

• Traditional whole-cell biocatalysis relies on heterotrophic microbes, necessitating carbohydrates for cofactor regeneration (ATP, NAD(P)H).
• This limits the sustainability and cost-effectiveness of biocatalytic processes for chemical synthesis.

Purpose of the Study:

• To develop a light-driven cofactor regeneration system using purple non-sulfur photosynthetic bacteria (PNSB) for enhanced biocatalysis.
• To optimize Rhodopseudomonas palustris as a biocatalyst for efficient, sustainable production of high-value chemicals.

Main Methods:

• Engineered a highly active conditional expression system in Rhodopseudomonas palustris.
• Implemented strategies to block side reactions, control substrate feeding, and mitigate light shading effects.
• Performed light-anaerobic biotransformations of ferulic acid, p-coumaric acid, and isoprenol.

Main Results:

• Achieved 100% conversion of 50 mM ferulic acid to vanillyl alcohol and >99.9% conversion of 50 mM p-coumaric acid to p-hydroxybenzyl alcohol.
• Obtained 92% conversion of 30 mM isoprenol to pinene, demonstrating pathway utility.
• Demonstrated efficient light-driven cofactor regeneration, eliminating the need for carbohydrates.

Conclusions:

• Rhodopseudomonas palustris is a promising host for light-powered biotransformation.
• This approach offers an efficient, green, and sustainable method for synthesizing value-added chemicals.
• Harnessing photosynthetic bacteria for biocatalysis opens new avenues for sustainable chemical production.