Super cyanobacteria and its sidekick – Power duo produces bioplastic faster and cheaper than ever before

October 28, 2017 |

You may know cyanobacteria by some more common forms like Spirulina, but researchers at Michigan State University are combining these handy microorganisms with natural bacteria to make a 100% biologically derived and biodegradable bioplastic. Making bioplastics from bacteria isn’t anything new, but what is new is MSU scientists’ new production method which allows them to do it faster, more efficiently, and much cheaper.

Researchers tweaked a cyano strain that naturally produces sugar to make them constantly leak the sugar into the surrounding salt water which had natural bacteria that fed off the leaked sugar and made bioplastic. So while cyanos work great at photosynthesis and creating chemical compounds, the natural bacteria munches up the sugar and converts it into bioplastic.

Taylor Weiss, a former post-doc in the MSU Ducat lab said, “Present bioplastic production relies on feeding plastic-producing bacteria with large quantities of sugars from crops, like corn or sugarcane. But these crops also feed people and animals, so we risk competing for limited agricultural resources and driving food prices up in the long term.”

After five months, they have some impressive stats that can really make a difference in turning these cyanobacteria/bacteria combos into feasible, cost effective bioplastic producers. According to their press release, production rates were over twenty times faster. Processed biomass contained a near constant 30% bioplastic content, four times more than the best cyano working alone. And the system is also relatively inexpensive to maintain.

Weiss said “Harvesting bioproducts is a common costly bottleneck. It involves collecting and regrowing microorganisms from scratch, each production cycle. But, we trap our cyanos in a hydrogel bead for reuse after each harvest.” Sounds like the ultimate feedstock that can be reused over and over and over again.

Another big plus is that the natural plastic-producing bacteria beat out other contaminating bacteria trying to get the sugar so human intervention was not needed to keep the process going, which also helps keep the costs down. “This pair has complementary strengths: the cyanos are constantly producing sugar, and the bacteria are constantly beefing up on it, which encourages the cyanos to keep producing,” said Weiss.

Other cyanobacteria superheroes

In California, surfer-turned-entrepreneur Rob Falken is looking to make shoes from cyanobacteria, as reported in NUU in November 2016. Falken’s company, Bloom, uses a mobile harvester to gather the algae biomass, which is then dried, pulverized, and pelleted. The pellets are then made into foam. Cyanobacteria, which depletes water oxygen levels, have proliferated because of climate change and water contamination. Traction pads, which surfers use to help grip and control their surfboards, are currently the only product currently for sale using Bloom’s foams. However, Falken aims to produce enough foam for 2 million pairs of shoes by early next year.

Cyanobacteria is also proving to be a potential valuable ingredient for sunscreens and moisturizers. As reported in NUU in January 2017, cyanobacteria are a particularly promising source of sunscreen ingredients because they can live in extremely arid climates and cope with both high ultraviolet radiation and extreme desiccation. Potential cyanobacteria-based ingredients include mycosporine-like amino acids and scytonemin, which provide strong screening protection from longwave and shortwave ultraviolet radiation respectively. Such photoprotectants could be effective alternatives to synthetic ultraviolet filters.

As reported in the Digest in August, a Bay Area, California company patented a group of three cyanobacteria that, when grown together, can produce high quantities of sugar just right for making biofuels. Sandia National Laboratories is helping HelioBioSys Inc. learn whether farming them on a large scale would be successful. The cyanobacteria have already proved successful in closed, controlled, sterile laboratories. Sandia researchers are now growing the cyanobacteria in large raceway systems that resemble long bath tubs. Though the raceways are indoors they are open to the air, so predation could prove a much bigger challenge.

Even the government is getting in on the cyanobacteria action with the U.S. DOE announcement of four additional projects from the Productivity Enhanced Algae and ToolKits funding opportunity, as reported in the Digest in September. One of the four projects is University of California, San Diego’s development of genetic tools, high-throughput screening methods, and breeding strategies for green algae and cyanobacteria, targeting robust production strains. The team will work with three key industrial partners: Triton Health and Nutrition, Algenesis Materials, and Global Algae Innovations.

Cyanobacteria is even a hurricane superhero when Hurricane Harvey turned the world’s most widely-produced chemical, ethylene, into something of a rarer commodity because of refinery slowdowns. As reported in the Digest in September, the U.S. Department of Energy is supporting a project to produce transportation fuels via photosynthetically derived ethylene. The research team notes that “steam cracking of petroleum, is the largest CO2 emitting process in chemical industry”. In this effort, they are using cyanobacteria to make biomass plus two products: ethylene, which self-separates from the culture, and is the only organic compound in headspace; and guanidine, a platform chemical and potential nitrogen fertilizer, as co-product from ethylene-forming reaction. The protein-rich biomass has potential as animal feed or feedstock for HTL.

The outlook

While there are many recent developments with cyanobacteria, MSU researchers are hoping to quickly improve the productivity and bioproduct line of their new bioplastic production method.

“We’ve laid the foundation for a “plug-and-play” system where a cyano can be gradually upgraded to produce more sugar,” said Weiss. “We eventually want to pair it with diverse specialist bacteria to create many cheaper, green bioproducts like fuels, fragrances, dyes, and medicines. Ultimately, we aren’t just creating alternatives to synthetic products. We’re figuring out how to ask Nature to do what it does best: figure out the problem for us.”

The new cyanobacteria and natural bioplastic producing bacteria combination seems like it could be the winning combo we desperately need. It could alleviate the food security issues that many are concerned about when moving from fossil fuel derives bioproducts to biobased ones that come from corn, sugarcane, or other crops.

If this new production method gains traction and produces as well in commercialization as it did in the lab, it really could be the future of bioplastics and biobased materials. The only obstacle might be getting consumers to eat from a bioplastic fork knowing it was made from bacteria.

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