Study sug­gests pro­bi­otic bac­te­ria and su­per­bugs can pro­duce elec­tric­ity

Iran Daily - - Science & Technology -

Sci­en­tists have dis­cov­ered that hun­dreds of bac­te­rial species are ca­pa­ble of pro­duc­ing elec­tric­ity and could very well be co-opted to cre­ate ‘liv­ing bat­ter­ies’.

Ac­cord­ing to in­, while re­searchers have known that bac­te­ria found in ex­otic en­vi­ron­ments like the ocean floor are elec­tro­genic, a new study pub­lished in the jour­nal Na­ture marks the first time sci­en­tists have un­cov­ered bac­te­ria in­ter­act­ing with hu­mans are also elec­tro­genic.

These bac­te­ria range from the sort that cause diar­rhea to the ones that fer­ment yo­gurt. Many fill the hu­man gut, and un­der­stand­ing how these bac­te­ria de­velop elec­tric­ity-pro­duc­ing ca­pa­bil­i­ties may re­veal how they in­fect hu­mans — or why they keep us healthy.

Study coau­thor and Univer­sity of California, Berke­ley post­doc­toral fel­low Sam Light told In­verse that over the past 30 years sci­en­tists have in­creas­ingly re­al­ized that bac­te­ria that live in en­vi­ron­ments rich in min­eral ox­ides, like iron ox­ide and man­ganese ox­ide, are able to sur­vive be­cause of a process called ex­tra­cel­lu­lar elec­tron trans­fer. This means they pro­duce elec­tric­ity as part of their me­tab­o­lism, Light said.

The rea­son why some bac­te­ria gen­er­ate elec­tric­ity is sim­i­lar to why we breathe oxy­gen: To sup­port en­ergy pro­duc­tion.

In the hu­man body, elec­trons are trans­ferred to oxy­gen mol­e­cules in the mi­to­chon­dria in­side ev­ery cell. But bac­te­ria liv­ing in our gut don’t have ac­cess to oxy­gen, so they have evolved the abil­ity to use al­ter­na­tives.

With ex­tra­cel­lu­lar elec­tron trans­fer, these mi­crobes can ‘breathe’ by mov­ing high en­ergy elec­trons out­side of the cell — in the form of elec­tric­ity.

“We made the dis­cov­ery that the food­borne pathogen Lis­te­ria mono­cy­to­genes has this elec­tric­ity-pro­duc­ing abil­ity,” Light ex­plained.

“We were able to iden­tify the genes that were re­spon­si­ble for this elec­tri­cal ac­tiv­ity, and it turns out that many other bac­te­ria pos­sess these genes, too — mean­ing that they can also make elec­tric­ity. Bac­te­ria with these genes in­clude other pathogens that cause dis­eases, probiotics, and nor­mal mem­bers of the mi­cro­bial com­mu­nity within our gut, as well as bac­te­ria used for food fer­men­ta­tion.”

The team dis­cov­ered that, when grown in a flask with elec­trodes, the bac­te­ria cre­ated an elec­tri­cal cur­rent mea­sured at 500 mi­croamps. This means that the elec­tric­ity they can make out­side of the body is 100,000 elec­trons per sec­ond per cell.

“I wouldn’t say that they’re mak­ing elec­tric­ity in­side our bod­ies,” Light elab­o­rated. “They’re sim­ply per­form­ing res­pi­ra­tion out­side their cells. In other words, they have a process that, out­side our body, can be co-opted to cre­ate elec­tric­ity.”

And that’s is of huge in­ter­est to sci­en­tists. In June NASA sent up elec­tric­ity-gen­er­at­ing bac­te­ria to the In­ter­na­tional Space Sta­tion to see if the mi­crobes still work the same in space. If they do, their elec­tric­ity could po­ten­tially be used to power mis­sion projects.

The US armed forces is also fi­nan­cially sup­port­ing elec­tro­genic bac­te­ria stud­ies with the hopes that the bac­te­ria can even­tu­ally be used to treat waste­water.

In 2017, sci­en­tists from the Univer­sity of California, Santa Bar­bara also made way to­ward the cre­ation of a ‘liv­ing bat­tery’ with a chem­i­cally mod­i­fied mi­cro­bial fuel cell.

Be­cause oxy­gen-less bac­te­ria pass elec­trons out of their cells walls as a means of sur­vival, if ma­nip­u­lated right they could con­trib­ute our sur­vival in in­tense en­vi­ron­ments as well.

Pub­lished in in­ Elec­tron mi­cro­graph of a flag­el­lated Lis­te­ria mono­cy­to­genes bac­terium.

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