Self-destructing microbe leads the way for lower-cost, renewable biofuels

WASHINGTON - An Arizona State University (ASU) research team has programmed a photosynthetic microbe to self-destruct, making the recovery of high-energy fats easier and potentially less costly, thus removing a key obstacle to producing lower-cost, renewable biofuels.

“The real costs involved in any biofuel production are harvesting the goodies and turning them into fuel,” said Roy Curtiss, director of the Biodesign Institute’s Center for Infectious Diseases and Vaccinology and professor in the School of Life Sciences.

“This whole system that we have developed is a means to a green recovery of materials not requiring energy dependent physical or chemical processes,” he added.

The ASU team has been focusing on optimizing photosynthetic microbes, called cyanobacteria, as a source of renewable biofuels.

These microbes are easy to genetically manipulate and have a potentially higher yield than any plant crops currently being used as transportation fuels.

But, until now, harvesting the fats from the microbes required many cost-intensive processing steps. yanobacteria have a multi-layer, burrito-like, protective set of outer membranes that help the bacteria thrive in even harsh surroundings, creating the pond scum often found in backyard swimming pools.

To get the cyanobacteria to more easily release their precious, high fat cargo, Curtiss and postdoctoral researcher Xinyao Liu, placed a suite of genes into photosynthetic bacteria that were controlled by the simple addition of trace amounts of nickel to the growth media.

“Genetics is a very powerful tool. We have created a very flexible system that we can finely control,” said Liu.

The genes were taken from a mortal bacterial enemy, called a bacteriaphage, which infect the bacteria, eventually killing the microbes by causing them to burst like a balloon.

The scientists swapped parts from bacteriaphages that infect E. coli and salmonella, simply added nickel to the growth media, where the inserted genes produced enzymes that slowly dissolved the cyanobacteria membranes from within.

This is the first case of using this specialized bacterial system and placing it in cyanobacteria to cause them to self-destruct.

“This system is probably one of a kind,” said Curtiss, who has filed a patent with Xinyao Liu on the technology. (ANI)