1. BIODEGRADABLE MICROBEAD ALTERNATIVE FOR COSMETICS BIODEGRADABLE MICROBEAD ALTERNATIVE FOR COSMETICS Celina Celmo & Meredith Addison Polyethylene / Polypropylene Effect on Marine Life Polyhydroxyalkanoates (PHA) What are microbeads? Small plastic exfoliating spheres made of synthetic polymers like polyethylene and/or polypropylene Found in cosmetic products such as face wash, moisturizer, lipstick, and toothpaste What is the problem? When an individual washes their face or brushes their teeth with a product containing microbeads, the beads are washed down the drain. Due to their size, they are not detected during water treatment, and end up reaching oceans, rivers, and lakes. Then they absorb toxins in the water, which poses a hazard to the fish that eat the now toxic microbeads. A study showed that over 663 different species were negatively impacted by marine debris with approximately 11% of reported cases specifically related to the ingestion of microplastics Polyethylene and polypropylene microbeads from cosmetic products, ranging in size from 50 μm to 500 μm (0.05 mm to 0.50 mm) A Suitable Replacement The accumulation of microplastics in oceans is becoming a permanent issue and microbeads are a large contributor to these numbers. Researchers have found that the Great Lakes contained a concentration as high as 600,000 microbeads per square kilometer. This had led to many states, including Illinois, California, and New York, introducing bans on the sale of items containing microbeads. A study on the distribution of plastic pollution in the world’s oceans has reported that microplastics account for 92.4% of plastic pollution by particle count and 13.2% by mass, totaling 35,540 tons of microplastics found. What are PHA? Biodegradable plastics that can be combined with more than 150 monomers, giving them a wide range of properties and applications PHA are created by living organisms and can be produced in a laboratory setting in which microbial organisms are multiplied at a controllable rate. Poly(3-hydroxybutyrate) (PHB) is a homopolymer of 3-hydroxybutrate and is the most widespread and best characterized member of the polyhydroxyalkanoate family due to its chemical properties and structure PHB exhibits properties such as thermoplasticity and biodegradability Chemical structure of some PHA, a) PH3B, b) PHV, c) PHBV PHA Production PHA as Biodegradable Plastics What is the solution? PHA plastics and traditional polypropylene and polyethylene plastics have very similar properties, which give PHA the potential as a microbead in cosmetics Naturally accumulated biodegradable PHA microbeads are an “ocean-safe” alternative to synthetic non-degradable microbeads. Sustainability How are they produced? PHA are produced by large-scale microbial fermentation The industrial production of PHA involves several processes including: PHA synthesis- PHA synthesize when there is a lack of an essential nutrient, such as nitrogen or phosphorus, and an excess supply of carbon sources. Strain development- PHA grow to high cell densities. Shake flask optimization- The contents from the previous step are optimized Industrial scale up- This is the final phase that involves two techniques called centrifugation and filtration. During this step, the cells are separated from the culture medium and finally the raw polymer is isolated. The enzymes involved in the fermentation process are not always specific, therefore a personalized substrate supply allows for the production of a wide variety of short or medium chain length monomers. The resulting monomer composition, as well as its properties, size, and structure can vary depending on the type of bacterium that was chosen to produce the PHA. Traditional polyethylene plastics float in marine waters and can take more than 100 years to disintegrate completely. On the other hand, polyhydroxyalkanoates, of any variation or composition, can biodegrade in either aerobic or anaerobic environments. PHAs are considered energy sources for microorganisms, therefore they biodegrade in microbial environments. Biodegradation of PHA on the marine environment compared with other polymers What properties of PHA allow it to be a microbead in cosmetics? Shape- Microbeads must be spherically shaped in order to properly exfoliate and cleanse the skin of the consumer. The process to make PHA plastics into spherically shaped microbeads is very similar to that of synthetic microbeads. Hardness- Microbeads must be sufficiently hard so that they cleanse the skin as desired. In PHA microbeads, there are specific monomer units that would enhance the hardness (at least 90% of hydroxybutrate (PHB) monomer units). Higher density- Synthetic microbeads have a low density of 1.0, causing them to float on the surface of water columns and eventually travel into the ocean. However PHA microbeads have a density of 1.3, allowing them to sink in water treatment plants and biodegrade before entering the environment. Biodegradation- This occurs when microorganisms settle on the surface of the polymer and secretes enzymes that break down into several units, which are then used for biomass growth. In other words, the bacteria dwelling in the ocean consider PHA as an energy source. Conclusion In conclusion, PHA plastics are a suitable replacement for polyethylene and/or polypropylene plastics used as microbeads in cosmetics because they have the ability to be made into appropriate exfoliants. Additionally, they are environmentally and economically sustainable, making them the replacement the cosmetics industry is looking for. Sustainability can be looked at as preserving the economy, environment and society in the most efficient ways possible PHA microbeads are a sustainable solution because they are produced and disposed in a way that protects the environment They are expensive to produce now, however methods to make them cheaper are being researched, making them even more sustainable