Study creates bacteria that consume carbon dioxide for growth

Agencies
November 30, 2019

Washington D.C., Nov 30: Researchers have developed bacteria called Escherichia coli, which consume carbon-di-oxide for energy instead of organic compounds.

This creation in synthetic biology highlights the incredible plasticity of bacterial metabolism and could provide the framework for future carbon-neutral bioproduction. The work appeared in the journal -- Cell.

"Our main aim was to create a convenient scientific platform that could enhance CO2 fixation, which can help address challenges related to the sustainable production of food and fuels and global warming caused by CO2 emissions," said senior author Ron Milo, at systems biologist at the Weizmann Institute of Science.

"Converting the carbon source of E. coli, the workhorse of biotechnology, from organic carbon into CO2 is a major step towards establishing such a platform," added Milo.

A grand challenge in synthetic biology has been to generate synthetic autotrophy within a model heterotrophic organism.

Despite widespread interest in renewable energy storage and more sustainable food production, past efforts to engineer industrially relevant heterotrophic model organisms to use CO2 as the sole carbon source has failed.

Previous attempts to establish autocatalytic CO2 fixation cycles in model heterotrophs always required the addition of multi-carbon organic compounds to achieve stable growth.

"From a basic scientific perspective, we wanted to see if such a major transformation in the diet of bacteria -- from dependence on sugar to the synthesis of all their biomass from CO2 -- is possible," said first author Shmuel Gleizer (@GleizerShmuel), a Weizmann Institute of Science postdoctoral fellow.

"Beyond testing the feasibility of such a transformation in the lab, we wanted to know how extreme an adaptation is needed in terms of the changes to the bacterial DNA blueprint," added Gleizer.

The researchers used metabolic rewiring and lab evolution to convert E. coli into autotrophs. The engineered strain harvests energy from formate, which can be produced electrochemically from renewable sources.

Because formate is an organic one-carbon compound that does not serve as a carbon source for E. coli growth, it does not support heterotrophic pathways.

They inactivated central enzymes involved in heterotrophic growth, rendering the bacteria more dependent on autotrophic pathways for growth.

They also grew the cells in chemostats with a limited supply of the sugar xylose -- a source of organic carbon -- to inhibit heterotrophic pathways.

The initial supply of xylose for approximately 300 days was necessary to support enough cell proliferation to kick start evolution. The chemostat also contained plenty of formates and a 10% CO2 atmosphere.

By sequencing the genome and plasmids of the evolved autotrophic cells, the researchers discovered that as few as 11 mutations were acquired through the evolutionary process in the chemostat.
One set of mutations affected genes encoding enzymes linked to the carbon fixation cycle.

The authors said that one major study limitation is that the consumption of formate by bacteria releases more CO2 than is consumed through carbon fixation.

In addition, more research is needed before it's possible to discuss the scalability of the approach for industrial use.

In future work, the researchers will aim to supply energy through renewable electricity to address the problem of CO2 release, determine whether ambient atmospheric conditions could support autotrophy, and try to narrow down the most relevant mutations for autotrophic growth.

"This feat is a powerful proof of concept that opens up a new exciting prospect of using engineered bacteria to transform products we regard as waste into fuel, food or other compounds of interest," Milo said.

"It can also serve as a platform to better understand and improve the molecular machines that are the basis of food production for humanity and thus help in the future to increase yields in agriculture," added Milo.

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Agencies
June 20,2020

At a time when the country is yet to recover from the shock of losing 20 Indian soldiers in a violent clash with the Chinese People's Liberation Army (PLA) troops in Ladakh's Galwan Valley, another shocker has come to light with news coming of a malware hitting the Indian Railways network and snooping its data for foreign countries, including train movements, sources in the intelligence agencies said on Friday.

Meanwhile, Railways Board Chairman V K Yadav said that the national transporter keeps on receiving malware security threats and the engineers in the railways keep on taking all precautions and keeps on updating the firewalls to prevent data theft.

The news comes a day after the Dedicated Freight Corridor Corporation Limited (DFCCIL) decided to terminate the 417-km signalling project worth Rs 471 crore with Chinese firm Beijing National Railway Research and Design Institute of Signal and Communication Group Company Limited (BNRRDISC) due to non-performance.

According to intelligence agency sources, the system of the Railways has been hit by the APT 36 Malware campaign. The source said that the intel agencies have also alerted the Railway Board to instantly disconnect the system with the Internet and change the password immediately.

The source said the APT 36 Malware is connected to Pakistan, which is a close ally of China. The source further said that following the red flag from the intel agencies, the system of a senior Principal Executive Director of the Railways, working in its vigilance department, has been taken for cleaning the malware threat.

As per the source, through the APT 36 Malware campaign, data stored in the Indian Railways systems were being stolen and stored in foreign locations, including the movement of the trains.

He further claimed that the APT 36 Malware also tried to take defence movement data. 

The source said the APT 36 Malware effect was reported from at least four systems of the Indian Railways.

Responding to queries, the Railways Board Chairman said: "Whether it is our systems or the IRCTC, we continuously update it with firewalls, and it is an ongoing process as we get the updates." 

Yadav said that our system is updated time to time. "We get malware threat on a regular basis. And we look at it continuously," he said. 

When pressed further about the malware threat in four railways systems, he said: "It has not come to our notice that some information has been leaked. Our systems are secure and our engineers keep on working on it."

According to intel sources, besides Railways, there was also malware threat in the defence, central police organisations, education and healthcare sectors, the source said.

In view of the threat, the intel agencies have asked the departments concerned to change the passwords of emails and online services from secure computers, format the hard-disk of the affected computers after taking back-up and re-install the operating systems and other softwares.

Sources in the Railways had said on Thursday that DFFCIL, which is looking after the work of the Dedicated Freight Corridor Project, has decided to terminate the tender with BNRRDISC.

A source in the Railway Ministry said that it has informed the Railway Board and the World Bank to take the final decision in the matter.

The source said the project was awarded to the Chinese firm in 2016 for signalling and telecommunication work on the 417-km Kanpur-Deen Dayal Upadhyaya section of the Eastern Dedicated Freight Corridor (EDFC). 

The source disclosed that the contract was awarded to the Beijing National Railway Research and Design Institute in June 2016. The source further said that even after four years, the progress in the project was only 20%. The issues that led to the termination of the project are reluctance by the company to furnish technical documents, as per the contract agreement, such as logic design of electronic interlocking.

The source further said that other issues like non-availability of their engineers and authorised personnel on site were a serious constraint. Even physical work could not progress as they have no tie-up with local agencies. 

The 3,373-km DFC, a flagship project of the Railways, aims to augment rail transport capacity to meet the growing requirement of movement of goods by segregating freight from passenger traffic.

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Agencies
July 8,2020

Scientists have designed a “catch and kill” air filter which they say can trap the novel coronavirus and neutralise it instantly, an invention that may reduce the spread of COVID-19 in closed spaces such as schools, hospitals and health care facilities, as well as public transit environments like airplanes.

According to the study, published in the journal Materials Today Physics, the device killed 99.8 per cent of the novel coronavirus, SARS-CoV-2, in a single pass through its filter. It said the device, made from commercially available nickel foam heated to 200 degrees Celsius, also killed 99.9 per cent of the spores of the deadly bacterium Bacillus anthracis which causes the anthrax disease.

“This filter could be useful in airports and in airplanes, in office buildings, schools, and cruise ships to stop the spread of COVID-19,” said Zhifeng Ren, a co-author of the study from the University of Houston (UH) in the US.

“Its ability to help control the spread of the virus could be very useful for society,” Ren added.

The researchers said they are also developing a desk-top model for the device which is capable of purifying the air in an office worker’s immediate surroundings. According to the scientists, since the virus can remain in the air for about three hours, a filter that could remove it quickly was a viable plan, and with businesses reopening across the world, they believe controlling the spread in air conditioned spaces was urgent.

The study noted that the novel coronavirus cannot survive temperatures above 70 degrees Celsius, so by making the filter temperature far hotter — about 200 degree Celsius, the researchers said they were able to kill the virus almost instantly.

Ren said the nickel foam met several key requirements. “It is porous, allowing the flow of air, and electrically conductive, which allowed it to be heated. It is also flexible,” the researchers noted in a statement.But they added that nickel foam also had low resistivity, making it difficult to raise the temperature high enough to quickly kill the virus.

The researchers said they solved this problem by folding the foam, connecting multiple compartments with electrical wires to increase the resistance high enough to raise the temperature as high as 250 degrees Celsius. By making the filter electrically heated, rather than heating it from an external source, they said the the amount of heat that escaped from the filter is minimised, allowing air conditioning to function with very low strain.

When the scientists built and tested a prototype for the relationship between voltage/current and temperature, they said it satisfies the requirements for conventional heating, ventilation, and air conditioning (HVAC) systems, and could kill the coronavirus.

“This novel biodefense indoor air protection technology offers the first-in-line prevention against environmentally mediated transmission of airborne SARS-CoV-2, and will be on the forefront of technologies available to combat the current pandemic and any future airborne biothreats in indoor environments,” said Faisal Cheema, another co-author of the study from UH.

The researchers have called for a phased roll-out of the device, “beginning with high-priority venues, where essential workers are at elevated risk of exposure.” They believe the novel device will both improve safety for frontline workers in essential industries and allow nonessential workers to return to public work spaces.

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