Engineering Microbes for Sustainable Manufacturing and Better Biofuels0

Ysabel Yates | Thu Oct 18 2012

Like mini-recycling plants, microbes ingest and break down material to create something new. Scientists around the world are now using bioengineering to harness and improve this processing power to apply it towards solving major environmental challenges.

Using microbes to create useful products is nothing new. Humans have been doing it for centuries to bake bread or brew alcohol, for example.  More recent techniques have employed microbes in green technology, where they are used in the production of biofuels and in the generation of electricity from waste.

But sometimes in a laboratory setting, using microbes that have been finely tuned by evolution is like trying to fit a square peg in a round hole. This is where bioengineering steps in.

Here are three recent examples of how bioengineering microbes could create better biofuels, more sustainable manufacturing, and even the possibility of settlements on Mars.

Synthetic Evolution

Using a non-food feedstock to create biofuels is better both environmentally and economically, which is why researchers from Iowa State University are working to turn corn stalks and sawdust into ethanol.

The process involves heating the feedstock until it becomes a sugar-rich bio oil, then unleashing microbes to feed on the oil and produce ethanol as a by-product. Unfortunately, the microbes have a bad reaction to some of the compounds in the oil, which prevents them from efficiently digesting it.

To work around this, the team is using a technique called directed evolution.

The method works by growing each generation of microbes in a higher concentration of the maligned compounds. Each time the microbes divide, their DNA is replicated, which leads to mistakes in the DNA. The researchers hope one of these mistakes will produce an improved microbe that is tolerant of the oil.

The team has already had some success; some of the newly evolved microbes are able to live in slightly higher concentrations of the compounds. Once the ideal microbe emerges, the researchers will analyze its genetic data in order to duplicate it, and will be on their way to creating better, more sustainable biofuels.

Manufacturing with Microbes

Professor Sang Yup Lee of the Korea Advanced Institute of Science and Technology envisions a future where depletion of natural resources is no longer a side effect of manufacturing plastics and producing conventional fuels and chemicals.

Lee is leading research on how to metabolically engineer Escherichia coli to make plastics, chemicals and fuels from renewable resources.

He and his colleagues recently published a paper detailing their method, which states that their work with E. coli “should be generally useful for developing other engineered organisms capable of producing various unnatural polymers by direct fermentation from renewable resources.”

Following up in a press release, Lee stated: “Bio-based production of chemicals and materials will play an increasingly important role in establishing a sustainable world. To make the bioprocess efficient and economically competitive, it is essential to improve the performance of microorganisms through systems metabolic engineering. From industrial solvents to plastics, an increasing number of products of everyday use will be produced through bioprocesses.”

Life on Mars

Is there life on Mars? There will be if we bring it there, which is the premise behind a new plan from NASA to transport engineered microbes to Mars that can be used to build structures on the red planet.

In the plan, detailed in New Scientist, the bacterium Sporosarcina pasteurii will be spliced with E.coli and fed urea – the main waste product of urine – to give it the ability to create calcium carbonate cements.

Using the cement, the rocky material on Mars can be packed together to create bricks.

Because microbes are lightweight and easy to transport, taking them to Mars in place of building materials would save energy and resources, not to mention be a way to put astronaut waste to good use.

Top image: An electron micrograph of E. coli. Courtesy of the Agricultural Research Service, accessed through Wikimedia Commons.