CRISPR’s impact on diesel is now

November 29, 2017 |

CRISPR technology will ultimately impact what we eat, wear, and how we maintain our health — and it just crashed successfully into the big party known as the Advanced Transportation revolution. Specifically, a new path to producing fuel molecules that replace diesel.

For some time we have seen tremendous activity around the development of CRISPR gene-editing technology — allowing scientists to directly clip and insert genetic material.

Now, Fuzhong Zhang, associate professor at the School of Engineering & Applied Science updated the Digest this week and noted that “We designed and then constructed a synthetic metabolic pathway inside the fast-growing E.coli by introducing genes from other species, including Staphylococus aureus, cyanobacteria and soil bacteria. By using CRISPR, we incorporated genes from different species with favorable traits into E.coli’s fatty acid pathway.”

Zhang’s research focuses on engineering metabolic pathways that, when optimized, allow the bacteria to act as a biofuel generator. In its latest findings, recently published in Biotechnology for Biofuels, Zhang’s lab used the best bits of several other species — including a well-known pathogen — to enable E.coli to produce branched, long-chain fatty alcohols (BLFLs).

As the research team indicates:

The intrinsic structural properties of branched long-chain fatty alcohols (BLFLs) in the range of C12 to C18 make them more suitable as diesel fuel replacements and for other industrial applications than their straight-chain counterparts. 

An attractive molecule range. While microbial production of straight long-chain fatty alcohols has been achieved, biosynthesis of BLFLs has never been reported.

What do you get from this approach? Yield and titer.

Yields? The research team “produced either odd-chain or even-chain BLFLs with high selectivity, reaching 70 and 75% of total fatty alcohols, respectively.

Titers? “The acyl-ACP and alcohol-producing modules were also extensively optimized to balance enzyme expression level and ratio, resulting in a 6.5-fold improvement in BLFL titers. The best performing strain overexpressed 14 genes from 6 engineered operons and produced 350 mg/L of BLFLs in fed-batch fermenter.

Staph to the rescue

Of all things, they’re getting an assist from the staph virus, which generally doesn’t do much except lead to human ailments like boils, food poisoning or toxic shock syndrome.

Zhang and his team determined that staph was particularly helpful to solve a common problem when manufacturing biofuel: The virulent pathogen was able to incorporate branches into its lipid. These branch structures dramatically lower the melting temperature of lipids and transform long-chain fatty alcohol from a waxy substance to a liquid that can be better used as a fuel under cold weathers.

Next R&D steps

Zhang says the next step involves moving the engineered metabolic pathway into a more industrial-relevant microbial host. His lab is current working with other Washington University labs towards this goal.

The CRISPR and transgenic backstory

Engage the hyper-drive: Synbio’s fastest are going faster, bigger as Kytopen, Ginkgo, Twist Biosciences, Arzeda, TeselaGen feel the need for speed

1 septillion reasons Dad’s CRISPR-Cas9 may already be Toast

Biotech’s biggest breakthrough: The Digest’s 2016 Multi-Slide Guide to CRISPR and Caribou Biosystems

Frontiers of gene-editing, and why Calyxt is one to watch

More on the story

Wen Jiang, James B. Qiao, Gayle J. Bentley, Di Liu, Fuzhong Zhang “Modular pathway engineering for the microbial production of branched-chain fatty alcohols” Biotechnology for Biofuels


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