PHA is made in a similar way to how you might make beer. Very large vats are filled with raw materials (currently used vegetable oil) and then microbes are added that feed off the oil, and a natural fermentation process sets in – not unlike what happens when bees make honey. Over time the microbes get fat with PHA. The PHA is then squeezed out of the bacteria to become resin to be used in manufacturing, and everything that is left can be used for animal feed. There tends to be zero waste from making PHA, and a net benefit diverting used cooking oils that otherwise might be disposed of improperly. Like how bakers would use a different yeast to make sourdough bread instead of wheat bread, specific microbes are chosen based upon the desired properties of the PHA production. Certain microbe strains will make a rigid type of PHA (for something like a single-use fork or knife) and others will make something more flexible (for something like straws). Mixing strains can create something in between. Another way to think about PHA production is envisioning an egg with the yolk being PHA and the egg whites and shell being the byproduct. As the eggs are harvested about 80% can be used for resin (the yolk) and the 20% left over (egg white and shell) can be used for animal feed. Once the raw resin is produced, the PHA is washed a few times and dried and becomes a soft power that looks and feels like baby powder. Since people tend to have a hard time handling powders it is melted into a pellet (about the size of a BB) to be used in production. To get different attributes, pellets made from varied strains are melted together into a new pellet. Companies like RWDC (www.rwdc-industries.com) compound specific PHA formulas based on the desired product application (e.g. films, coated papers, straws). They also work to make it easy for customers to “bake the cake” from the PHA. For example, most people if they are baking a cake don’t want to buy flour and other ingredients separately. They prefer having everything prepackaged to make it as easy as possible (e.g. just add water and stir). This type of prepackaged approach by companies like RWDC makes it easy and increases the likelihood of consistent quality and performance in PHA products.

Currently PHA has been proven a worthy replacement for plastic straws, films, cups, and coated papers. There is currently ongoing work to replace polyester fibers (a leading culprit of microplastics when clothes are washed), but those applications are quite complex and will take more time to develop. Companies like Cove (www.cove.co) are making some of the first water bottles made from PHA.

PHA is stable and only degrades when microbes eat it. If a PHA product is at a normal temperature sitting on the shelf it will stick around like how a plastic straw will stick around. However, if you put a PHA product in soil it will start composting back to nature as the bugs and microbes eat it. If you have lots of bugs and a small amount of PHA then it will compost very quickly. If you have a few bugs and lots of PHA then it will take longer. Another way to think about it is a coffee table book that sits on your table for a very long time. After many years it might yellow a bit, but it will still be functional as a book. If you put that same book in the backyard, it wouldn’t take long until it started to degrade. After a while, it would no longer be recognizable as the book it once was.

For big parts (say a block of PHA) we recommend grinding it so that there is more surface area for bugs to eat them, and smaller pieces will break down faster. We hope at some point people will have PHA grinders in their homes and can sprinkle the shavings in their garden or put in a home compost bin. It might not taste great, but you could also add some shavings to your morning cereal. It is that safe for animals and humans.

Currently used vegetable oils are the primary feedstock for our PHA. Sugars can be used but are about 1/3 as efficient as oils (needing 3 kg of sugar to make the same amount of PHA with 1 kg of oil). Some companies like Newlight Technologies (www.newlight.com) are pulling carbon from the atmosphere to make PHA. Currently, no one has found a microbe that will eat CO2 efficiently so the yields are much lower than oils and sugars. The good news is that carbon from the atmosphere is free. The bad news is it currently takes much more time and energy to get enough feedstock for the microbes to make PHAs. If research can be done to find new bacterial strains that efficiently produce PHA from carbon it would dramatically help scale PHA production as well as reduce carbon emissions.

We believe that the brand owners and companies that pioneer replacing plastics in their current products and packaging will be rewarded with long-term profits and market share. Our hope is that chemical and petroleum companies will eventually want to diversify their risk and supply chains by joining the PHA movement, and build their own PHA production facilities.

PLA is a type of polyester made from fermenting starch primarily from corn but it can also come from sugarcane, sugar beets, maize and cassava. The starch is turned into lactic acid and then a chemical process is used to bind together the monomers from fermentation to make polylactic acid. This required chemical process is why PLA is man-made and not found in nature. PHA on the other hand is found in nature as the PHA fermentation process creates the entire polymer. PLA is a great replacement for petroleum-based plastics but if not composted properly it will break down into toxic microplastics. As those microplastics become smaller and smaller they become more and more dangerous to humans and animals. With PHA as it breaks down into smaller and smaller pieces it becomes less harmful because the material degrades faster the smaller it gets.

Just because something says it is compostable doesn’t mean it is being composted. Many industrial composters sell their composted piles after 30 days to farmers and others looking to improve soil structure and health. Since PLA takes on average much longer (90 to 120 days) to compost, many industrial composters will not process PLA. We like PLA, and it is surely better than plastic, but we must ensure it is used properly and there is the sufficient industrial composting capability that will compost it fully. We don’t recommend PLA in developing countries where there is limited industrial composting. Also, when burned (a standard practice in the developing world) it will release toxic chemicals harmful to humans.

Just because something says it is compostable doesn’t mean it is being composted. Many industrial composters sell their composted piles after 30 days to farmers and others looking to improve soil structure and health. Since PLA takes on average much longer (90 to 120 days) to compost, many industrial composters will not process PLA. We like PLA, and it is surely better than plastic, but we must ensure it is used properly and there is the sufficient industrial composting capability that will compost it fully. We don’t recommend PLA in developing countries where there is limited industrial composting. Also, when burned (a standard practice in the developing world) it will release toxic chemicals harmful to humans.

Think of PHA in the environment like you would a piece of wood floating in the ocean. Swimmers and surfers might not like the wood in the water as the debris can be ugly and might hit them, but no one on the beach is yelling “oh my gosh we have to get that wood out of the water!”. PHA is natural and it will degrade in nature as other natural materials would. At the same time, we still need PHA to be properly disposed of as it will take time for PHA straws and bags to break down even in a marine environment. No one wants to see any more turtles with straws stuck in their noses.

Even though most plastics are “technically” recyclable, in most instances plastic is rarely recycled. Even in the United States, most items put in recycling bins are incinerated or landfilled. In developing countries, many lack municipal waste systems so plastics are often burned in open fires next to communities and households. This is both bad for the environment and for human health, especially for young children. PLA when heated releases lactide which isn’t harmful to humans but when burned releases Volatile Organic Carbons (VOCs) that are toxic to humans if inhaled or ingested. PLA is also highly flammable which could cause additional safety risks. Developing countries tend to have limited industrial composting capabilities making it more likely that PLA products will degrade into harmful microplastics in the environment. PHA will offer the additional opportunity to home compost materials in developing countries and, if burned releases crotonic acid. Crotonic acid can still cause irritation to humans, but is much less toxic than plastic and PLA when burned. Also, PHA offers fewer safety risks as it will ignite if a flame is applied, but will likely stop burning if the flame is removed due to some naturally self-extinguishing properties of the material. Hence, we believe PHA is a more flexible and long-term solution to our plastic crisis, especially in developing nations.

PHA for use in 3D Printing. PLA did a great job in replacing ABS plastics in 3D printing as it prints at lower temperatures and doesn’t release toxic gases like ABS does when heated. PLA is also easy to use and many home hobbyists set their machines to print complex parts, and 8 hours later come back to find it printed without problems. The main challenge with PLA printing tends to be the waste genarated. PLA is rarely fully composted in an industrial facility and is likely destined to become toxic microplastics in our environment. Using PHA filament for 3D printing will generate similar waste but that waste will have additional options for disposable including home composting. We believe this will especially be attractive for businesses such as jewelry makers that tend to make one-time printed mockups for customers and throw them away after. We do expect some advantages in PHA printing compared to PLA as PLA tends to get brittle over time, and parts can snap or shatter if force is applied. PHA filament for 3D printing will likely be more expensive than PLA at the beginning but over time the raw material cost will go down as PHA production increases.

- The companies that spent billions to build polyolefin plants around the world will lobby against the use of PHA to replace the plastics films and foams currently being used in most single-use packaging. - Current manufacturers won’t want to change or learn new ways of doing things. Manufacturers inexeperienced with PHA will likely try and run PHA in existing machines at high temperatures resulting in burning the polymer instead of learning to manufacture their products at lower temperatures. - People are betting on chemical recycling to solve our problems. The US government doesn’t consider chemical recycling actual recycling and we see it is only valid for reclaiming very expensive things. The cost and energy required to process low-value plastics are not economical. - Waste management promoting sustainable landfills. Layering waste in landfills in the right manner can potentially generate methane to run power plants or trucks that pick up our waste. Capturing methane from landfills is better than nothing, but we do not believe it to be a good long-term solution. Only 6-8 percent of landfills in the US are managed this way, and many things escape from landfills, especially when not managed properly.

- The development of new green/plastics credits to incentivize the replacement of plastics in products instead of just giving credits to those that are using recycled material in products. - The identification and development of new microbes that can efficiently consume C02 (is this how we should do CO2?) to make PHA. - More investment in the production of PHAs around the world. With a limited supply, it will be difficult initially for PHAs to compete with polyethylene and other petroleum-based polymers. At scale, PHA will be competitive in cost and performance to plastic while offering better end-of-life options.