Tag Archives: predator bacteria

How to Make Carbon-Negative Chemicals

Bacteria engineered to turn carbon dioxide into compounds used in paint remover and hand sanitiser could offer a carbon-negative way of manufacturing industrial chemicals.

Michael Köpke at LanzaTech in Illinois and his colleagues searched through strains of an ethanol-producing bacterium, Clostridium autoethanogenum, to identify enzymes that would allow the microbes to instead create acetone, which is used to make paint and nail polish remover. Then they combined the genes for these enzymes into one organism. They repeated the process for isopropanol, which is used as a disinfectant.

The engineered bacteria ferment carbon dioxide from the air to produce the chemicals. “You can imagine the process similar to brewing beer,” says Köpke. “But instead of using a yeast strain that eats sugar to make alcohol, we have a microbe that can eat carbon dioxide.” After scaling up the initial experiments by a factor of 60, the team found that the process locks in roughly 1.78 kilograms of carbon per kilogram of acetone produced, and 1.17 kg per kg of isopropanol. These chemicals are normally made using fossil fuels, emitting 2.55 kg and 1.85 kg of carbon dioxide per kg of acetone and isopropanol respectively.

This equates to up to a 160 per cent decrease in greenhouse gas emissions, if this method were to be broadly adopted, say the researchers. The technique could also be made more sustainable by using waste gas from other industrial processes, such as steel manufacturing.

Excerpt from Chen Ly, Engineered bacteria produce chemicals with negative carbon emissions, New Scientist, Feb. 21, 2022

How to Kill Bacteria: Robo-Cells

Johns Hopkins University researchers are setting out to design and test self-directed microscopic warriors that can locate and neutralize dangerous strains of bacteria…[The goal] s to devise a prototype biocontrol system that can dispatch single-cell fighters to track down and engulf specific pathogens, rendering them harmless. The funding was awarded by the Defense Advanced Research Projects Agency, commonly called DARPA.

Possible first targets in this proof-of-concept project include Legionella, the bacteria that cause Legionnaire’s disease; and Pseudomonas aeruginosa, a bacterial strain that is the second-leading cause of infections found in hospitals. If the project succeeds, these tiny infection-fighters might one day be dispatched to curtail lethal microbes lurking in medical settings. Eventually, they could also be used to cleanse contaminated soil or possibly defend against bioterror attacks.

An important goal of the project is that each of the proposed soldier cells must carry out its own mission without relying on step-by-step commands from a remote human operator.

“Once you set up this biocontrol system inside a cell, it has to do its job autonomously, sort of like a self-driving car,” said Pablo A. Iglesias.”…In a similar way, the biocontrol systems we’re developing must be able to sense where the pathogens are, move their cells toward the bacterial targets, and then engulf them to prevent infections among people who might otherwise be exposed to the harmful microbes.”

These experts plan to biologically embed search-and-surround orders within a familiar type of amoeba cell called Dictyostelium discoideum [slime mold]. These widely studied microbes, commonly found in damp soil such as riverbeds, typically engulf and dine on bacteria, which are much smaller.  “These amoebas possess receptors that can detect the biochemical ‘scents’ emitted by bacteria,” Robinson said. “Our goal is to use concepts from control theory to design a ‘super amoeba’ that can recognize a particular bad guy—a specific type of disease-causing bacteria—and then move toward and attack these target cells.”  Robinson added: “The plan is to develop amoebas that are super-sensitive to these bacterial signals and home in on them as though they were a plate piled high with fresh chocolate chip cookies. The goal is to make these amoebas behave as though this is the most natural thing to do.”.. But if the project is successful, the researchers say the single-cell fighters could eventually be introduced into the cooling and ventilation system in a hospital, where they could feast on the bacteria that are currently causing dangerous infections. One possible method of introducing the infection fighters into such systems might be through use of a spray solution.

Iglesias noted that initial efforts will focus on bacteria lurking outside, not within the body.  “In this contract, we are not targeting bacteria in human blood,” he said, “but the hope is that the techniques we develop would ultimately be useful for that.”

Excerpts from Phil Sneiderman, Johns Hopkins researchers aim to design self-driving cells to pursue deadly bacteria, John Hopkins University, Feb. 2, 2016

Predator Bacteria for War

The  Pathogen Predators Program of DARPA would represent a significant departure from conventional antibacterial therapies that rely on small molecule antibiotics. While antibiotics have been remarkably effective in the past, their widespread use has led to the emergence of antibiotic-resistant bacterial infections that are difficult or impossible to treat. In vitro studies have shown that predators such as Bdellovibrio bacteriovorus and Micavibrio aeruginosavorus can prey upon more than one hundred different human pathogens and will also prey on multi-drug resistant bacteria.

The Pathogen Predators program will answer three fundamental questions about bacterial predators:

1) Are predators toxic to recipient (host) organisms?
2) Against what pathogens (prey) are predators effective?
3) Can pathogens develop resistance to predation?

This list [of bacteria that could be killed by predator bacteria] includes NIAID (National Institute of Allergy and Infectious Diseases) Category A and B threats to national security:

NIAID Category A and B
Yersinia pestis (i.e. plague)
Francisella tularensis (i.e. tularemia)
Brucella species
Coxiella burnetii (i.e. Q fever)
Rickettsia prowazekii (i.e.  typhus)
Burkholderia mallei (i.e. glanders)
Burkholderia pseudomallei (i.e. melioidosis)

Source DARRA (pdf)