We know photosynthesis is a feature of plants which absorb sunlight and use the energy to convert atmospheric CO2into glucose. While sunlight peaks in the 400-700 nm region (of wavelengths), scientists have shone ultraviolet radiation (well below 400 nm) on plants and found that this opens new avenues in enzyme engineering and drugs through photocatalysis — the process of using light to jumpstart chemical reactions.
Light-activated enzymes turn light energy into chemical action. In some cases, light triggers lightning-fast shape changes that turn on the enzyme. These movements can now be tracked in real-time on a scale of trillionths of a second using ultra-fast imaging.
Researchers at Nanjing University, China, have used visible light to trigger inherent enzymes as catalysts, paving the way for manufacturing useful products and drugs. This technology, called ‘photobiocatalysis’, repurposes natural enzymes to produce novel products of medicinal value (Organic Chemistry Frontiers, 12 (16), April 2025, pages).
Photobiocatalysis pairs the energy of light with the precision engineering of enzymes, allowing scientists to assemble very complex structures.
Use of microbes, bacteria
Some plants have been found to contain an alkaloid called securinine. The genes that make this alkaloid resemble bacterial genes and have been borrowed from bacteria that invade plants. This discovery has allowed scientists to look for more such repurposed genes in plants and find new paths for drug discovery. These use the molecules offered by microbes in order to produce new defence molecules that are toxic.
Taking a cue from this transfer of genes seen in nature, scientists have engineered the yeast Pichia pastoris, which is found in the soil, to help produce two plant-derived anti-cancer drugs called vinblastine and vincristine (Nature Synthesis, 2, 231-242, 2023). These alkaloids, found in the periwinkle plant, are very complex molecules that are put together by the coordinated action of 30 enzymes.
There is also increasing use of intact organisms like mice or zebrafish, and even the bacterial workhorse Escherichia coli to produce novel chemicals of use in agriculture or medicine.
Driven by light
İbrahim İncir and Özlem Kaplan from the genetics and bioengineering faculty of Antaya University, Türkiye, have shown that E. coli is a versatile cell factory, which has been used to produce novel and useful products such as insulin and other cost-effective proteins of medical interest. Scientists at Kobe University, Japan have similarly used E. coli to produce pyridine dicarboxylate, a degradable plastic (Nature Chemical Biology 21, 1171–1181 (2025)).
And researchers from DuPont, Wilmington, Delaware have used E. coli to convert glucose to an industrial styrene polymer (Metabolic Engineering vol. 9, issue 3, May 2007). Likewise, Ajikumaran et al. from the Massachusetts Institute of Technology in the U.S. have used E. coli to synthesise the precursor of the anti-cancer drug Taxol.
The most recent application of combining photobiosynthesis with a microbial ‘bioreactor’ has come from the group of Huimin Zhao at the University of Illinois, Urbana-Champaign, who have engineered E. coli to produce non-natural olefins and reductases directly from glucose using enzymes activated by blue light.
Using E. coli allows scientists to scale the process up for large scale production, where they combine biosynthesis with photo-biotechnology (Nature Catalysis vol. 9, January 2026, pages 62-72). They also point out that this approach has the potential for large-scale chemical production where reactions driven by light are integrated into cellular metabolism.
dbala@lvpei.org
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