New discovery turns seaweed into biofuel in half the time

Aug 29, 2011

University of Illinois scientists have engineered a new strain of yeast that converts seaweed into biofuel in half the time it took just months ago. That's a process that's important outside the Corn Belt, said Yong-Su Jin, a University of Illinois assistant professor of microbial genomics and a faculty member in its Institute for Genomic Biology.

"The key is the strain's ability to cellobiose and simultaneously, which makes the process much more efficient," Jin said.

Red , hydrolyzed for its fermentable sugars, yields glucose and galactose. But yeast prefers glucose and won't consume galactose until glucose is gone, which adds considerable time to the process, he said.

The new procedure hydrolyzes cellulose into cellobiose, a dimeric form of glucose, then exploits a newly engineered strain of Saccharomyces cerevisiae capable of fermenting cellobiose and galactose simultaneously.

The team introduced a new sugar transporter and enzyme that breaks down cellobiose at the intracellular level. The result is a yeast that consumes cellobiose and galactose in equal amounts at the same time, cutting the production time of biofuel from marine biomass in half, he said.

The research, performed with project funding from the Energy Biosciences Institute, included team members Suk-Jin Ha, Qiaosi Wei, and Soo Rin Kim of the University of Illinois, Urbana-Champaign, and Jonathan M. Galazka and Jamie Cate of the University of California, Berkeley.

Jin compared the previous process to a person taking first a bite of a cheeseburger, then a bite of pickle. The process that uses the new strain puts the pickle in the cheeseburger sandwich so both foods are consumed at the same time.

Co-fermenting the two sugars also makes for a healthier yeast cell, he said.

"It's a faster, superior process. Our view is that this discovery greatly enhances the economic viability of marine biofuels and gives us a better product," he added.

Is seaweed a viable biofuel? Jin and his colleagues are using a red variety (Gelidium amansii) that is abundant on the coastlines of Southeast Asia. In island or peninsular nations that don't have room to grow other crops, using seaweed as a source of biofuels just makes good sense, he noted.

But biofuels made from marine biomass also have some advantages over fuels made from other biomass crops, he said.

"Producers of terrestrial biofuels have had difficulty breaking down recalcitrant fibers and extracting fermentable sugars. The harsh pretreatment processes used to release the sugars also result in toxic byproducts, inhibiting subsequent microbial fermentation," he said.

Jin cited two other reasons for use of seaweed biofuels. Production yields of marine plant biomass per unit area are much higher than those of terrestrial biomass. And rate of carbon dioxide fixation is much higher in marine biomass, making it an appealing option for sequestration and recycling of carbon dioxide.

Explore further: The microbes make the sake brewery

More information: The study appears in Applied and Environmental Microbiology and is available online at www://aem.asm.org/cgi/content/full/77/16/5822

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PPihkala
5 / 5 (1) Aug 29, 2011
One more benefit of marine biomass: They use salty water, so the fresh water is left for other uses, namely human and animal food.
Osiris1
1 / 5 (1) Aug 29, 2011
Looks like a solution to a large problem. Better for CO2 sequestration, more of it, more efficient conversion, no load on valuable farmland, no use of freshwater, lots of energy, no load on world's food supply....can our other readers think of more?
danlgarmstrong
not rated yet Aug 30, 2011
Might have good export potential - use a hundred square miles to farm seaweed - solar energy to process - we have plenty of tankers to ship product. Why isn't big energy jumping at production of sea based biofuel? Seems to be a no brainer - you could even develop a biofuel industry in international waters to escape taxation. Seasteading anyone?
ricarguy
1 / 5 (1) Aug 30, 2011
An entirely new species invented to solve a problem and it seems to work. Sounds great. What happens when this new "bug" gets out into the world? This one may or may not be a problem, but what about the next one or the next one?

What we have here is a Frankenstein-mutant, and a potential man-made invasive species. I admit it sounds great on the surface. But there are often unintended consequences to this kind of tinkering, just as there has been with the ongoing "chemical revolution". Yet with that you can just ban a "bad" chemical. Any issue with this is likely irreversible.

I admit I sound like the geek scientist nay-sayer in "Jurassic Park", but there are consequences in playing with life, especially microscopic life. Hope someone thought about that part of the equation.
ricarguy
1 / 5 (1) Aug 30, 2011
By the way, I hope I'm totally wrong, but I doubt it.
Shakescene21
1 / 5 (1) Aug 30, 2011
Another advantage to farming seaweed (and oceanic algae) is that 70 percent of the Earth's surface is ocean. This is the next logical place for billions of humans to "settle" in the 21st Century and beyond. Farming seaweed and harvesting wind and wave power could provide the economic base for these new settlements.