Plastics are always, first and foremost, a scientific endeavor and should reflect the principles of science as the bottom line. If the principles of science are sound, provable, and repeatable — as all scientific developments should be — then profits, the other bottom line, will follow. That holds true for new advanced technologies that include various recycling methods beyond mechanical recycling, as well as the development of new types of plastics, specifically bio-based plastics made from plants, biodegradable polymers, and polymers made from enzymes, sugars and various plant oils.
Companies get into trouble when they allow the science of what is possible overshadow what is actually achievable and scalable from a business standpoint and focus instead on attracting investors. That has been happening to many new companies seeking to replace traditional plastics and, in the process, harvesting headlines they likely wish they hadn’t.
Yes, it’s possible, but . . .
Polyhydroxyalkanoates (PHAs) fall into the category of possible but not highly achievable and scalable technologies. Companies such as Danimer Scientific and RWDC Technologies, Yield 10, and others I’m not aware of are touting PHAs as replacement materials for traditional thermoplastics. As explained in Plastics and Sustainability (second edition), Plastics and Sustainability – Grey Is the New Green by Michael Tolinski and Conor P. Carlin, “The term PHA comprises a family of biopolyesters created via fermentation processes within different bacteria found in various natural environments. These same kinds of bacteria also degrade and consume PHA polymer products after they are disposed of.”
That is the closest thing yet we’ve come to making plastics disappear, as so many anti-plastics (and anti-science) groups wish would happen. Tolinski and Carlin explain that “various bacteria and enzymes produce different PHAs with various structures; over 150 PHA monomer structures have been reported.” The authors note that this process has been studied and researched for “the past couple of decades” by some well-known companies such as Procter & Gamble and Metabolix Inc., which began experimenting with bacteria and PHA/PHB in 1992.
Metabolix created a variety of switchgrass “that produces significant amounts of polyhydroxybutyrate (PHB) bioplastic in leaf tissues,” said a notice in Biomass Magazine (ca 2007). Then Metabolix President and CEO Richard Eno said, “This technology could advance the development of cellulosic biofuels . . . which could also make switchgrass a more lucrative crop for producers to grow.” Metabolix formed a joint venture with Archer Daniels Midland (ADM) Co. in 2007 called Telles, with a stated goal of producing PHB under the brand name Mirel. A facility to be built in Clinton, IA, would produce 110 million pounds of Mirel PHB per year. The plant was expected to be operational in the second quarter of 2009.
“Mirel plastic resins can be used in standard plastic applications from lipstick tubes to disposable coffee containers and lids to agricultural mulch film,” said Biomass Magazine, which noted that a detailed scientific paper on this technology, “Production of Polyhydroxybutyrate in Switchgrass, a Value-Added Coproduct in an Important Lignocellulosic Biomass Crop,” was published in Plant Biotechnology Journal.” (That paper can be found at onlinelibrary.wiley.com.)
In January 2012, ADM announced an end to the venture with Metabolix because it was not delivering on the promised results. By the end of 2014, Metabolix announced it was ending its adventure to pursue commercializing performance additive solutions based on PHA biopolymers. According to a report in Bioplastics News magazine (Oct. 8, 2014), Metabolix “has been engaged primarily in the marketing and sale of compounded resins used in compostable film and bag applications.”
From Metabolix to Yield10
Metabolix restructured in 2015, because its ventures into crop technology to produce PHB — the simplest product of the PHA family of biopolymers — was losing too much money. Yield10 Bioscience was formed as a spinoff from Metabolix. Yield10 was working to develop “new genetic informatics tools” to begin “capturing intellectual property around strategies to enhance the photosynthetic capacity of plants. . . . Our team has demonstrated yield improvements in switchgrass biomass and camelina oilseed, and we are developing innovative agricultural biotechnology approaches in significant row crops to provide novel solutions for global food security,” Yield10 told Bioplastics News (no date given on the article).
In March 2016, Metabolix and South Korea’s CJ Cheiljedang (CJ), a food and bioengineering company, signed a “memorandum of understanding for a strategic commercial manufacturing arrangement for specialty PHAs, including the company’s newly launched amorphous PHA, in what was thought to be the way of bringing Metabolix much closer to realizing its vision for large-scale production,” said the announcement. “Under that agreement, CJ was to fund, construct, and operate a PHA production unit at its Fort Dodge, IA, facility, based on Metabolix’s PHA technology.”
In May 2016, Metabolix stated that it was “exploring strategic alternatives” for its specialty biopolymers business and Yield10. “The firm has struggled financially, posting losses of nearly $24 million in 2015, and $29.5 million in 2014,” said an article posted on CHEManager’s online news site. On July 25, 2016, Metabolix announced it was “quitting the biopolymers business and instead turning its focus to develop its Yield10 crop science program launched in 2015. Just one month later, on Aug. 25, 2016, CHEManager posted another announcement from Metabolix that it had “officially exited the bioplastics business with the sale of its intellectual property and certain laboratory equipment to South Korea’s CJ for $10 million.”
This extensive chronological exercise was done to show readers how long one company struggled with the attempt to manufacture PHB/PHA at scale, not to mention the hundreds of millions of dollars investors have put into turning the scientific possibility into a profitable reality. Does this hurt you to read this? It does me. Now you know why Tolinksi and Carlin say in their book, “These materials [PHA and PHB] have been tailored for plastics conversion processes for creating packaging and other (mainly) non-engineering plastics applications, though achieving commercial scale has proven expensive and difficult.” (That’s putting it mildly!) “The production of PHA polymers is more like a harvesting operation than a chemical synthesis process,” state the authors, who then provide a summary of the basic steps required to make PHA.
In an article in phys.org, “The Truth about Bioplastics,” published on Dec. 14, 2017, Renee Cho writes that “PHA is made by microorganisms, sometimes genetically engineered, that produce plastic from organic materials. The microbes are deprived of nutrients like nitrogen, oxygen, and phosphorous, but given high levels of carbon. They produce PHA as carbon reserves, which they store in granules until they have more of the other nutrients they need to grow and reproduce. Companies can then harvest the microbe-made PHA, which has a chemical structure similar to that of traditional plastics.”
The difficulty of manufacturing PHA at commercial scale
Tolinski and Carlin also note that Danimer Scientific, which will produce biodegradable polymer from canola oil at its Winchester, KY, plant, has “signed an exclusive agreement with US-based Genpak to provide PHA for takeout food containers. Attempts to reach Genpak by phone to inquire about material deliveries and confirm the agreement with Danimer have been unsuccessful. However, it’s easy to see why manufacturing PHA to commercial scale is so incredibly expensive and difficult.
Abstracts on the Science Direct website offer good information. In an article under the heading of Industrial Biotechnology and Commodity Products, G.Q. Chen, S.Y. Lee, et al. wrote in Comprehensive Biotechnology (Second Edition, 2011), “Polyhydroxyalkanoates (PHAs) are a family of bacterially synthesized biopolyesters with biodegradability, biocompatibility, thermoprocessability, and flexible strengths. . . . PHAs have found applications in the form of packaging material including films, boxes, coating, fibers, foam materials, biofuels, medical implants, and drug-delivery carriers.
“For large-scale applications such as biodegradable packaging materials, the cost and properties of PHAs are very important. Over the past years, process development and metabolic engineering approaches have been adopted to develop recombinant PHA production strains for improving the strains’ ability to produce PHA, and for changing the PHA structures to obtain better thermal and mechanical properties.” The authors’ article describes major past and recent achievements in PHA/PHB.
In another article abstract under Environmental Biotechnology and Safety, M. Reis, et al., also in Comprehensive Biotechnology (Second Edition, 2011), describe and discuss PHAs. “PHAs are a group of biologically synthesized polyesters that are considered promising eco-efficient bioplastics because they are both biobased and biodegradable, thus meeting the criteria of a closed loop life cycle. In the past decades, industrial biotechnology has devoted a considerable effort to PHA production by bacterial pure culture fermentation. However, PHAs have not yet entered bulk materials markets due to high production costs. The combined use of mixed microbial cultures (MMCs) and low-value feedstocks is currently under investigation in order to decrease operating costs. For the sake of enhanced PHA production, mixed cultures have to be preliminarily enriched in PHA-accumulating organisms. This is usually carried out under dynamic feeding of suitable carbon sources to create transient conditions of excess and lack of carbon availability, designated as feast and famine. PHA production is then usually carried out in a subsequent PHA accumulation state. To make waste- and surplus-based feedstocks suitable for PHA production, acidogenic fermentation is used to convert their organic fraction into volatile fatty acids, which are viable precursors for mixed culture PHA synthesis.”
In a paper appearing online titled, “Can Polyhydroxyalkanoates Be Produced Efficiently from Waste Plant and Animal Oils?” (March 2020), Manoj Lakshmanan, Jiun Yee Chee, Azlinah Mohd Sulaman, Doan Van Thuoc, and Kumar Sudesh note that “plant and animal oils have been demonstrated to be excellent carbon sources for high-yield production of PHAs. . . . Waste streams from oil mills or the used oils, which are even cheaper, are also used. This approach not only reduces the production cost for PHAs, but also makes a significant contribution toward the reduction of environmental pollution caused by the used oil.”
In the introduction to this paper, the authors write that these “fascinating biopolymers” represent a possible alternative to thermoplastics from fossil fuels, thus helping to reduce the use of fossil fuels as well as greenhouse emissions. PHAs have been thoroughly investigated with the expectation that they can “replace some of today’s petro-plastics . . . The PHA Market Research Report used by the authors for their paper, states that “the market opportunity for PHA is expected to reach almost USD 98 million by the year 2024.”
High cost of PHA production a major hurdle
However, the authors wrote, “[D]espite a significant number of studies on PHA and increasing market demand, the deployment of PHAs into the market is still in its early stages. One of the major restrictions for the wide commercialization and industrialization of PHAs is the high cost of production. One of the major reasons for their high cost is the price of the carbon substrate used in the microbial cultivation process, which can account for 45 to 50% of the total production cost.
Thus “there is a need to find cheap and efficient alternative substrates to improve the sustainability and economic feasibility of PHA production.”
Tolinski and Carlin discuss the end-of-life of PHAs, noting that “PHAs are much more biodegradable in common natural environments, outside of controlled composting conditions.” That statement appears to support the position that I have long taken that bioplastics in general are designed to be left in the environment, which is the one big problem these bioplastics producers are attempting to solve by making products that biodegrade.
“Various PHA/PHB polymer and copolymer grades are naturally biodegradable in soil or even marine environments,” said Tolinski and Carlin, adding the caveat that “marine biodegradation is impeded by cold water temperatures and limited microbial activity.”
The point to all of this — including the recent investigation by Spruce Point — is not that PHA can’t be produced or that is it not biodegradable — it can be produced and it is biodegradable. The proof is that science has been experimenting with this process for nearly three decades. Companies have been trying to use various materials to make PHA a commercially viable endeavor, yet no one is making PHAs to scale that can support the production of millions of water bottles or retail bags or other high-volume requirements. It’s been tried and tested, and yet the costs continue to be prohibitive, one of the primary details of Spruce Point’s report on Danimer.
With a projected “market opportunity” for PHA to reach “almost USD 98 million by the year 2024,” it would appear to be a “niche market at best, and that is only if the production costs can be reduced. Large-scale commercial production that promises to replace traditional thermoplastics and solve the plastic waste problem continues to be elusive, no matter how much money is thrown at it.