The SuperFriends and Their Planet-saving Microbial Biofuel Powers

Mom taught you well, I’ll bet. Swat the flies, pour disinfectant on a slimy mold, and shock a pool or pond that has algae in it. Never touch anything riddled with a fungus, avoid bacteria like the plague. If you see a termite, call Orkin, and if you see e.coli (well you wouldn’t, unless you have Superman-like vision, but you get the idea), run screaming into the night. Of course, in biofuels, you don’t avoid any of the above.

In the world at large, they are generally called pests. We call them “magic bugs.” They are like the SuperFriends of Saturday morning cartoons — Nature has certainly endowed them with magic powers.

In your own human genome, you have the (considerably useful) ability to break down a pretty good range of biomass into energy. Anything from the sugar rush from a Coca-Cola to the complex sea of carbohydrates and proteins in contemporary pizza. We’ve planted the world over with things that grow fast and we like to eat.

But make a carbohydrate, protein or lipid from thin air, with a little water and maybe a little sunshine? No can do. That’s where the magic bugs come in.

Beyond microalgae

Too often, public curiosity over microbial fuels begins and ends with microalgae. But there are two ways these other critters serve the general search for an energy solution.

  1. Fermenting one low-value material into a higher-value one. For instance, converting hops into beer, corn mash into ethanol, or sugar cane syrup into alkane diesel.
  2. Fixing atmospheric CO2, and freshwater or sea-water, into lipids, carbs and protein, which we capture and convert to feed, food, fiber and fuel.

Bottom lime, some mighty business models are depending on the unpaid services of some awfully small and occasionally icky organisms. Ranging from one cell to small insect size.

The yeoman service of the Soldier Fly

A company called Organic Nutrition is training soldier fly larvae to eat waste biomass, thereby converting it into insect protein. The hungry little varmints eat as much as twice their own body mass per day. The aggregated insect protein is captured and crushed as animal feed. Kind of an appalling food source, but a lot of critters like insects just fine, thank you very much.

It appears to be a re-think of an older company called Neptune Industries, which disappeared to the bottom of the financial ocean a few years back.

Termites and their Symbiotic Liberation Army

Over at Purdue, research into the extreme environments in the termite gut, including termite’s own native enzymes, and symbiontic bacteria, is the subject of some breakthroughs out of the Mike Scharf lab. Researchers there, publishing in PLoS One, have discovered a cocktail of enzymes instrumental in the insects’ ability to break down the wood they eat.

The researchers are the first to measure the sugar output from enzymes created by the termites themselves and the output from symbionts, small protozoa that live in termite guts and aid in digestion of woody material.

“For the most part, people have overlooked the host termite as a source of enzymes that could be used in the production of biofuels. For a long time it was thought that the symbionts were solely responsible for digestion,” Scharf said. “Certainly the symbionts do a lot, but what we’ve shown is that the host produces enzymes that work in synergy with the enzymes produced by those symbionts. When you combine the functions of the host enzymes with the symbionts, it’s like one plus one equals four.”

In Florida, researchers at the University of Florida have isolated two enzymes termites use to break up lignin, which may provide a key to more efficient cellulosic ethanol production. The study follows more than two years of work to identify nearly 7,000 genes associated with the termite gut. The researchers are wading through the genes to identify which ones are associated with enzymes that could be useful, and they are hopeful that many more such exciting discoveries are yet to come.

Monster fungus, mighty yeast

In California, researchers at the University of California, Berkeley and Lawrence Livermore National Laboratory has taken genes from Neospora crassa, a fungus that grows on grass and transplanted them into yeast that is already used to turn sugar into ethanol into what may be a more efficient process for cellulosic ethanol.

With the new technique, cellulose must only be broken down into an intermediate stage known as cellodextrin, rather than into glucose, and the new yeast will get to work. It could be five years before the new technique is ready for commercial use.

In related news, the DOE has granted researchers at the University of California, Berkeley-hosted Energy Biosciences Institute $793,000 for a three-year program to study the genetic diversity of corn to create better strains for biofuels.

In this story from last year, “Turn and Face the Strange,” we looked at WWII canvas rotting fungi as a biomass conversion technology, a fungus that produces diesel, a fungus that synthesizes ethanol, one that produces cellulase, and a symbiotic garden of fungi managed by leafcutter ants to assist in their leaf-converting activities.

But the topper was the news that up to 90 percent of Missouri’s Conservation Reserve Program land, where fescue is running rampant, may be infected with ergot (a fungus from which LSD is synthesized).

“A heft amount of carbon is sequestered by endophyte-infected fescue, so it has some carbon benefit. But that is courtesy of its ability to powerfully eradicate microbial life in its growing path and, by creating a nanoscopic, underground Chernobyl, storing carbon that otherwise would be munched and released by those pesky organisms known as life forms.”

In Illinois, researchers from the University of Illinois, the Lawrence Berkeley National Laboratory, the University of California and BP have discovered a newly engineered yeast strain that can simultaneously consume both glucose and xylose from plants to produce ethanol. The new strain, made by combining, optimizing and adding to earlier advances, reduces or eliminates several major inefficiencies associated with current biofuel production methods.


In Maryland, Johns Hopkins researchers have engineered from scratch a computer-designed yeast chromosome and incorporated into their creation a new system that lets scientists intentionally rearrange the yeast’s genetic material.  Jef D. Boeke, Ph.D., Sc.D., professor, explains, “We developed SCRaMbLE to enable us to pull a mutation trigger — essentially causing the synthetic chromosome to rearrange itself and introducing changes similar to what might happen during evolution, but without the long wait.”

“By shuffling the DNA according to our specifications,” Boeke added, “we hope to be able to custom design organisms that perhaps will grow better in adverse environments, or maybe make one percent more ethanol than native yeast.”

In Germany, researchers at the Ruhr-Universität and a group from the Tokyo Institute of Technology have found a genetic switch in cyanobacteria, which when removed allows use of excess energy for biotechnological purposes, such as hydrogen production.

Professor Roegner of Ruhr-Universität estimated, “This should make it possible to use at least 50 percent of the energy gained from light-driven water splitting for other processes in the future, e.g. for solar-powered biological hydrogen production through cyanobacterial mass cultures in photobioreactors.”

Pass the salt, I need sugar

In New Jersey, Proterro has developed technology to produce sugar by using engineered cyanobacteria, photosynthetic organisms that can produce sucrose through a normally-occurring defense system. Their engineered cyanobacteria produces sucrose when the water they’re growing in is too salty. They claim that the water required to grow the cyanobacteria is much less than what is required to grow sugar traditionally, such as with corn and cane.

Your friend, E.coli bacteria

In the article “Microbial Biosynthesis of Alkanes” published in Science magazine last year, a team of LS9 scientists announced the discovery of novel genes that, when expressed in E.coli, produce alkanes, the primary hydrocarbon components of gasoline, diesel and jet fuel. This discovery is the first description of the genes responsible for alkane biosynthesis and the first example of a single step conversion of sugar to fuel?grade alkanes by an engineered microorganism.

For over 20 years scientists have tried to identify the genes that enable particular natural organisms to directly convert biomass into alkanes. However, previous scientific research has failed to identify these genes. To solve this mystery, the LS9 team looked into the genomes of bacteria that produce alkanes in nature known as cyanobacteria. “We evaluated many cyanobacteria that made alkanes and identified one that was not capable of producing them. By comparing the genome sequences of the producing and non?producing organisms, we were able to identify the responsible genes,” said Andreas Schirmer, Associate Director of Metabolic Engineering at LS9.

The mysterious Archaea

In Arkansas, researchers at the University of Arkansas created the first methane-producing microorganism that can metabolize complex carbon structures, which could lead to microbial recycling of waste products and their transformation into methane.  Daniel J. Lessner, assistant professor of biological sciences, and his colleagues Lexhan Lhu, Christopher S. Wahal and James G. Ferry of Pennsylvania State University worked with methanogens, methane-producing anaerobic microorganisms from the domain archaea.

The researchers introduced a gene into a methanogen that would allow it to break down more complex molecules for its own consumption by introducing a gene that would cause the organism to express an enzyme that breaks down esters.  Esters can be found in nature and also solvents used in paints and paint thinners.  Future research will look at developing a platform to engineer organisms, including a methanogen that can break down glycerol, a waste product from biodiesel fuel, and have it produce methane, allowing for possible production of useful chemicals or even as an energy source for a biodiesel plant.

This article was originally published on Biofuels Digest and was reprinted with permission. 

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