Light Accelerates Conductivity In Nature’s ‘Electric Grid’
The natural world has its own intrinsic electrical grid composed of a world web of tiny bacteria-generated nanowires in the soil and seas that “breathe” by exhaling excess electrons.
In a new study, Yale College researchers found that light is an unexpected ally in fostering this electronic activity within biofilm bacteria. Revealing bacteria-produced nanowires to light, they found, generated an up to a 100-fold increase in electrical conductivity.
The findings were released Sept. 7 in the journal Nature Communications.
The dramatic current increases in nanowires exposed to light show a stable and robust photocurrent that persists for hours
Senior author Nikhil Malvankar, associate professor of Molecular Biophysics and Biochemistry (MBB) at Yale’s Microbial Sciences Institute on Yale’s West Campus
Benefiting from the ‘electrical grid’
The results can supply new insights as researchers seek ways to exploit this hidden electrical current for various purposes. They range from eliminating biohazard waste and to creating fresh renewable fuel sources.
Almost all living things breathe oxygen to eliminate excess electrons when transforming nutrients into energy. However, without access to oxygen, dirt bacteria living deep under oceans or hidden underground over billions of years have developed a way to respire by “breathing minerals,” like snorkeling, with tiny protein filaments called nanowires.
When bacteria were exposed to light, the increase in electric current astounded researchers. The surprise is because most bacteria tested existed deep in the soil, far from the reach of light. Previous studies revealed that nanowire-producing bacteria grew faster when exposed to light.
A new perspective
“Nobody understood how this happens,” Malvankar said.
In the new study, a Yale group led by postdoctoral scientist Jens Neu and graduate student Catharine Shipps concluded that a metal-containing protein known as cytochrome OmcS makes up bacterial nanowires– acts as a natural photoconductor. The nanowires significantly enable electron transfer when biofilms are exposed to light.
“It is a totally different kind of photosynthesis,” Malvankar said. “Here, light accelerates breathing by bacteria due to fast electron transfer between nanowires.”
Malvankar’s lab is exploring how this insight into bacterial electrical conductivity could be utilized to spur development in optoelectronics– a subfield of photonics that studies systems and devices that find and control light– and catch methane, a greenhouse gas known to be a significant factor to global climate change.
Other paper authors are Matthew Guberman-Pfeffer, Cong Shen, Vishok Srikanth, Sibel Ebru Yalcin from the Malvankar Laboratory at Yale; Jacob Spies, Professor Gary Brudvig, and Professor Victor Batista from the Yale Department of Chemistry; and Nathan Kirchhofer from Oxford Instruments.
Read the original article on PHYS.
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