For over a decade, companies have promised a future of renewable fuel from algae. Investors interested in moving the world away from fossil fuel have contributed hundreds of millions of dollars to the effort, and with good reason. Algae replicate quickly, requiring little more than water and sunlight to accumulate to massive amounts, which then convert atmospheric CO2 into lipids (oils) that can be harvested and readily processed into biodiesel.
Despite high-profile demonstrations, promises have fallen short, and start-ups have revised business models to include production of specialty lipids, such as those used in cosmetics and soaps. Yet the dream of producing commercial-scale renewable energy persists, as new technologies emerge that might finally lead algal biofuels toward a competitive niche in the marketplace.
One of many improvements necessary for sustainable production of algal biofuel is the development of better algae. This week, researchers from Boyce Thompson Institute and Texas A&M University report in Plant Direct exciting new technology that may revolutionize the search for the perfect algal strain: Algal droplet bioreactors on a chip.
A single algal cell is captured in a tiny droplet of water encapsulated by oil - imagine the tiny droplets that form when you mix vegetable oil with water - then millions of algal droplets squeeze onto a chip about the size of a quarter. Each droplet is a micro-bioreactor, a highly-controlled environment in which algal cells can grow and replicate for several days, forming a genetically homogenous colony that goes through its typical biological reactions, including the production of lipids.
"This is the first microsystem that allows both lipid content analysis and growth rate measurement at high throughput, whereas previous work could only do one or the other," remarked senior author and engineer, Arum Han of Texas A&M University.
Scientists are racing to identify a super algal strain that can reproduce faster and produce more lipid per cell. This summer, ExxonMobil announced the discovery of a strain with a single genetic modification that allows for twice as much lipid production per cell. But this is only a step in the right direction, as thousands of genes hold potential for further improving both traits.
With today's gene-editing technologies, modifying algal genes can be relatively straightforward; however, identifying which genes to target is time-consuming and costly. Exposing an algal culture to a mutagen yields millions of unique, potentially improved algal cells that must each be tested for expression of a desired trait, such as increased lipid production. Mutated genes can then be identified through whole-genome sequencing.
"The important thing is to develop a tool that can screen millions of cells in a much shorter time frame and a smaller space. In a chip housing millions of droplets of cells, each droplet is like a flask or a bioreactor, and that's how we can get results faster from just a tiny chip," explained author and BTI post-doc, Shih-Chi Hsu.
The researchers first validated the chip system with algae known to grow faster or slower, or produce more or less lipid. They then screened 200,000 chemically mutated cells, identifying six mutants with both faster growth and higher lipid content. The screening, done on-chip, uses fluorescence detection of chlorophyll, representing total cell mass, and BODIPY, a fluorescent molecule that binds to lipids. All mutants with potential for improved growth or lipid production were recovered and verified off-chip.
While the results of this study are promising, 200,000 is still a low number of mutants compared to what is needed to find that super algal strain. "The most extraordinary variants will be found in one in a million, or ten million, so the throughput needs to be accelerated," explained senior biologist and BTI President, David Stern.
Excitingly, the tools for improving throughput are already in development, including larger chips that can screen millions of droplets in one experiment. "Such high-throughput technologies can rapidly accelerate the development process to obtain strains that are more efficient for use in biofuel production," Han remarked.
With the discovery and development of much more efficient algal strains, commercial-scale production of biofuel from algae may finally be a realistic promise.
Alexa Schmitz | EurekAlert!
OHIO professor Hla develops robust molecular propeller for unidirectional rotations
22.08.2019 | Ohio University
In cystic fibrosis, lungs feed deadly bacteria
22.08.2019 | Columbia University Irving Medical Center
Theoretical physicists at Trinity College Dublin are among an international collaboration that has built the world's smallest engine - which, as a single calcium ion, is approximately ten billion times smaller than a car engine.
Work performed by Professor John Goold's QuSys group in Trinity's School of Physics describes the science behind this tiny motor.
Together with the University of Innsbruck, the ETH Zurich and Interactive Fully Electrical Vehicles SRL, Infineon Austria is researching specific questions on the commercial use of quantum computers. With new innovations in design and manufacturing, the partners from universities and industry want to develop affordable components for quantum computers.
Ion traps have proven to be a very successful technology for the control and manipulation of quantum particles. Today, they form the heart of the first...
Experimental progress towards engineering quantized gauge fields coupled to ultracold matter promises a versatile platform to tackle problems ranging from condensed-matter to high-energy physics
The interaction between fields and matter is a recurring theme throughout physics. Classical cases such as the trajectories of one celestial body moving in the...
Soft robots have a distinct advantage over their rigid forebears: they can adapt to complex environments, handle fragile objects and interact safely with humans. Made from silicone, rubber or other stretchable polymers, they are ideal for use in rehabilitation exoskeletons and robotic clothing. Soft bio-inspired robots could one day be deployed to explore remote or dangerous environments.
Most soft robots are actuated by rigid, noisy pumps that push fluids into the machines' moving parts. Because they are connected to these bulky pumps by tubes,...
Researchers at TU Graz are working together with European partners on new possibilities of measuring vehicle emissions.
Today, air pollution is one of the biggest challenges facing European cities. As part of the Horizon 2020 research project CARES (City Air Remote Emission...
16.08.2019 | Event News
14.08.2019 | Event News
12.08.2019 | Event News
22.08.2019 | Life Sciences
22.08.2019 | Physics and Astronomy
22.08.2019 | Physics and Astronomy