LS9 is on a quest to make renewable fuel at $50 a barrel, and today it is revealing at least part of the scientific road map it’s been following to get there.
The South San Francisco-based biofuel company is reporting today that it has discovered novel genes from strains of cyanobacteria that are the basis for a one-step process that converts sugars into alkanes—the primary component of gasoline, diesel, and jet fuel. The discovery and methods used to find these genes are being disclosed online today in Science magazine.
The paper is an important step for LS9, which has already gotten its share of attention because of its ambitious science, prominent founders, big money backers, and the enormous societal problem it is seeking to solve. The company was founded in 2005 by UC Berkeley’s Jay Keasling, Chris Somerville of the Energy Biosciences Institute, and Harvard University’s George Church. LS9 has raised more than $45 million since its beginning from Flagship Ventures, Khosla Ventures and Lightspeed Ventures. The people and the money have rallied behind the idea of swapping a few enzymes inside bacteria so that instead of converting sugars into fatty acids, they could become super-efficient engines for converting sugars into fuels.
LS9 has talked generally about its concept before, but today’s paper in Science is the first to show in detail how a handful of people at the company actually identified the genes in publicly available databases. Competitors like Cambridge, MA-based Joule Biotechnologies and several academic labs have also been on the hunt for these genes, but LS9 says it was confident enough to lay out its scientific methods in a top journal because the patent applications have already been filed and it believes it owns the process.
“It’s a major achievement,” says Andreas Schirmer, the associate director of metabolic engineering at LS9, and the study’s lead author.
These are still very early days in the renewable fuel business, and LS9 has only performed small-scale runs with this process in 1,000-liter tanks at its South San Francisco-based facility. A much more important test for the business will come later this year, as it seeks to reproduce the same process at industrial-sized scale, as I described in a company profile last month. And this is far from the end of the road. LS9 is actively working now to better characterize and optimize the bacterial enzymes that are produced by the genes to create an ever-more efficient process that can really hum at commercial scale.
But today’s news is about the science, so that’s what I asked Schirmer about the most. For more than two decades, scientists had sought to enable natural organisms to convert biomass into alkanes. There are examples in nature of organisms that can pull off this nifty trick in trace quantities, but nobody had been able to pinpoint the genes that carry the instructions for making enzymes that carry out that task.
The LS9 team benefitted from the era of genomics, in which scientists now have public access to vast databases of genome sequences for all sorts of species, including many different strains of cyanobacteria (also known as blue-green algae). The company’s scientists looked at some of these bacteria that made alkanes, and some that didn’t, and compared their genomes for differences. That helped narrow down the search for the right gene considerably, to make the experiments go quickly, Schirmer says.
In the end, LS9 identified two key enzymes at the heart of the process for creating alkanes. Once those enzymes were identified, it was really just the beginning. The bacteria strains that produced the enzymes weren’t very valuable on their own, because they weren’t very efficient, and could only produce minute quantities of alkanes, Schirmer says. So LS9 transferred the genes for those enzymes into a standard industrial workhorse bacteria, E.coli, which could pump out much greater quantities of the alkanes inside a fermentation vat.
The one-step sugar-to-fuel process is considered vital to the LS9 business model, Schirmer says. It’s valuable because it lets nature “do all the work” while other processes some companies are using create a chemical intermediate that requires further refining in order to become fuel.
“This scientific discovery made by the LS9 team is game changing for our company and the advanced biofuels industry,” said Bill Haywood, the company’s CEO, in a statement.
Still, scientists are bound to raise plenty of queestions about this new method. One of the peer reviewers of the paper asked the company to further characterize one of the two key enzymes, an aldehyde decarbonylase, which hadn’t been identified before. This scientist wanted to know more about how this enzyme performs this task, in concert with other metabolites and precursors in the biological pathway. It’s not just an academic question, because better understanding of the molecular environment could lead to further modifications of the process that could make production much more efficient, Schirmer says.
“You could argue that maybe the enzyme as it works now in E. coli is only 20 percent efficient, and if you knew it better, you could get to 100 percent,” Schirmer says. “In order to ask question of how efficient it is, you need additional information. That’s enzymology,” and a further task that’s outside the scope of today’s publication, Schirmer says.
LS9 is now focused on better understanding of the enzymes at work, and how to make the process more efficient, Schirmer says. But as he points out, there wouldn’t be any real way to dive into that question without first pinpointing the genes that might be able to help make fuel cheaply enough to power cars, trucks, and jets.
“If you really want to develop a process of making alkanes, the knowledge of the genes is a foundation for it,” Schirmer says.
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