Mini ‘solar panels’ help yeast shine at churning out drug ingredients

Covering microbes with light-harvesting semiconductors boosted shikimic acid production

yeast cell

SEMICONDUCTOR GETUP  A yeast cell (magenta) coated in semiconductor nanoparticles (purple), shown in this false-color scanning electron microscopy image, creates useful chemicals better than an uncoated cell does.

Wyss Inst./Harvard Univ.

Bionic microbes outfitted with tiny semiconductor components can generate useful chemicals more efficiently than normal cells.

Microorganisms like fungi are commonly used in biomanufacturing to convert simple carbon-based molecules, such as sugar, into a wide range of chemical ingredients for pharmaceuticals and other products. But much of a microbe’s carbon intake typically gets used to power the creature itself, cutting the amount available to form desired chemicals.

In the new setup, described in the Nov. 16 Science, microbial cells are coated in semiconductor nanoparticles that absorb and transfer energy from sunlight to the cell, similar to the way rooftop solar panels supply energy to a house. That process allows the cell to funnel carbon it would normally use as a fuel toward its chemical output instead.

Chemical and biological engineer Neel Joshi of Harvard University and colleagues tested this scheme using baker’s yeast cells covered in nanoparticles made of the semiconductor indium phosphide. Baker’s yeast consumes the sugar glucose to produce shikimic acid, which is used to make the flu medication Tamiflu. In lab experiments, cyborg microbes equipped with nanoparticles produced about three times as much shikimic acid as normal baker’s yeast fed the same amount of glucose.

Light-harvesting nanoparticles could boost the chemical output of other microbes, as well, such as yeast cells that generate benzylisoquinoline alkaloids, the family of chemicals that includes morphine (SN Online: 6/17/15). Microbe-semiconductor hybrids could also increase the production of ingredients for multivitamins, fragrances, renewable fuels and other materials.

Previously the staff writer for physical sciences at Science News, Maria Temming is the assistant managing editor at Science News Explores. She has bachelor's degrees in physics and English, and a master's in science writing.

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