Bioplastics are often touted as being eco-friendly, but do they live up to the hype?
HuaWei Product Page
The world has produced over nine billion tons of plastic since the s. 165 million tons of it have trashed our ocean, with almost 9 million more tons entering the oceans each year. Since only about 9 percent of plastic gets recycled, much of the rest pollutes the environment or sits in landfills, where it can take up to 500 years to decompose while leaching toxic chemicals into the ground.
Traditional plastic is made from petroleum-based raw materials. Some say bioplastics'made from 20 percent or more of renewable materials'could be the solution to plastic pollution. The often-cited advantages of bioplastic are reduced use of fossil fuel resources, a smaller carbon footprint, and faster decomposition. Bioplastic is also less toxic and does not contain bisphenol A (BPA), a hormone disrupter that is often found in traditional plastics.
Kartik Chandran, a professor in the Earth and Environmental Engineering Department at Columbia University who is working on bioplastics, believes that compared to traditional plastics, 'bioplastics are a significant improvement.'
However, it turns out that bioplastics are not yet the silver bullet to our plastic problem.
Since there is often confusion when talking about bioplastics, let's clarify some terms first.
Degradable ' All plastic is degradable, even traditional plastic, but just because it can be broken down into tiny fragments or powder does not mean the materials will ever return to nature. Some additives to traditional plastics make them degrade more quickly. Photodegradable plastic breaks down more readily in sunlight; oxo-degradable plastic disintegrates more quickly when exposed to heat and light.
Biodegradable ' Biodegradable plastic can be broken down completely into water, carbon dioxide and compost by microorganisms under the right conditions. 'Biodegradable' implies that the decomposition happens in weeks to months. Bioplastics that don't biodegrade that quickly are called 'durable,' and some bioplastics made from biomass that cannot easily be broken down by microorganisms are considered non-biodegradable.
Plastic and Styrofoam not breaking down in a municipal compost pile. Photo: CkgurneyCompostable ' Compostable plastic will biodegrade in a compost site. Microorganisms break it down into carbon dioxide, water, inorganic compounds and biomass at the same rate as other organic materials in the compost pile, leaving no toxic residue.
Bioplastics are currently used in disposable items like packaging, containers, straws, bags and bottles, and in non-disposable carpet, plastic piping, casings, 3D printing, car insulation and medical implants. The global bioplastic market is projected to grow from $17 billion this year to almost $44 billion in .
There are two main types of bioplastics.
Starch from wheat is converted to plastic. Photo: CSIROPLA (polylactic acid) is typically made from the sugars in corn starch, cassava or sugarcane. It is biodegradable, carbon-neutral and edible. To transform corn into plastic, corn kernels are immersed in sulfur dioxide and hot water, where its components break down into starch, protein, and fiber. The kernels are then ground and the corn oil is separated from the starch. The starch is comprised of long chains of carbon molecules, similar to the carbon chains in plastic from fossil fuels. Some citric acids are mixed in to form a long-chain polymer (a large molecule consisting of repeating smaller units) that is the building block for plastic. PLA can look and behave like polyethylene (used in plastic films, packing and bottles), polystyrene (Styrofoam and plastic cutlery) or polypropylene (packaging, auto parts, textiles). Minnesota-based NatureWorks is one of the largest companies producing PLA under the brand name Ingeo.
PHA (polyhydroxyalkanoate) is made by microorganisms, sometimes genetically engineered, that produce plastic from organic materials. The microbes are deprived of nutrients like nitrogen, oxygen and phosphorus, 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. Because it is biodegradable and will not harm living tissue, PHA is often used for medical applications such as sutures, slings, bone plates and skin substitutes; it is also used for single-use food packaging.
While bioplastics are generally considered to be more eco-friendly than traditional plastics, a study from the University of Pittsburgh found that wasn't necessarily true when the materials' life cycles were taken into consideration.
The study compared seven traditional plastics, four bioplastics and one made from both fossil fuel and renewable sources. The researchers determined that bioplastics production resulted in greater amounts of pollutants, due to the fertilizers and pesticides used in growing the crops and the chemical processing needed to turn organic material into plastic. The bioplastics also contributed more to ozone depletion than the traditional plastics, and required extensive land use. B-PET, the hybrid plastic, was found to have the highest potential for toxic effects on ecosystems and the most carcinogens, and scored the worst in the life cycle analysis because it combined the negative impacts of both agriculture and chemical processing.
3D printed PLA teapot. Photo: CreativeToolsBioplastics do produce significantly fewer greenhouse gas emissions than traditional plastics over their lifetime. There is no net increase in carbon dioxide when they break down because the plants that bioplastics are made from absorbed that same amount of carbon dioxide as they grew. A study determined that switching from traditional plastic to corn-based PLA would cut U.S. greenhouse gas emissions by 25 percent. The study also concluded that if traditional plastics were produced using renewable energy sources, greenhouse gas emissions could be reduced 50 to 75 percent; however, bioplastics that might in the future be produced with renewable energy showed the most promise for substantially reducing greenhouse gas emissions.
While the biodegradability of bioplastics is an advantage, most need high temperature industrial composting facilities to break down and very few cities have the infrastructure needed to deal with them. As a result, bioplastics often end up in landfills where, deprived of oxygen, they may release methane, a greenhouse gas 23 times more potent than carbon dioxide.
Recycled PET. Photo: MichalManasWhen bioplastics are not discarded properly, they can contaminate batches of recycled plastic and harm recycling infrastructure. If bioplastic contaminates recycled PET (polyethylene terephthalate, the most common plastic, used for water and soda bottles), for example, the entire lot could be rejected and end up in a landfill. So separate recycling streams are necessary to be able to properly discard bioplastics.
The land required for bioplastics competes with food production because the crops that produce bioplastics can also be used to feed people. The Plastic Pollution Coalition projects that to meet the growing global demand for bioplastics, more than 3.4 million acres of land'an area larger than Belgium, the Netherlands and Denmark combined'will be needed to grow the crops by . In addition, the petroleum used to run the farm machinery produces greenhouse gas emissions.
Bioplastics are also relatively expensive; PLA can be 20 to 50 percent more costly than comparable materials because of the complex process used to convert corn or sugarcane into the building blocks for PLA. However, prices are coming down as researchers and companies develop more efficient and eco-friendly strategies for producing bioplastics.
Kartik Chandran and Columbia students are developing systems to produce biodegradable bioplastic from wastewater and solid waste. Chandran uses a mixed microbe community that feeds on carbon in the form of volatile fatty acids, such as acetic acid found in vinegar.
His system works by feeding wastewater into a bioreactor. Inside, microorganisms (distinct from the plastic-producing bacteria) convert the waste's organic carbon into volatile fatty acids. The outflow is then sent to a second bioreactor where the plastic-producing microbes feed on the volatile fatty acids. These microbes are continually subjected to feast phases followed by famine phases, during which they store the carbon molecules as PHA.
Chandran is experimenting with more concentrated waste streams, such as food waste and solid human waste, to produce the volatile fatty acids more efficiently. The focus of his research is to both maximize PHA production and to integrate waste into the process. 'We want to squeeze as much as we can [out of both systems],' said Chandran.
He believes his integrated system would be more cost-effective than the methods currently used to produce bioplastic that involve buying sugars to make PHA. 'If you integrate wastewater treatment or address food waste challenges with bioplastic production, then this is quite favorable [economically],' said Chandran. 'Because if we were to scale up and go into commercial mode, we would get paid to take the food waste away and then we would get paid to make bioplastics as well.' Chandran hopes to close the loop so that, one day, waste products will routinely serve as a resource that can be converted into useful products like bioplastic.
Full Cycle Bioplastics in California is also producing PHA from organic waste such as food waste, crop residue such as stalks and inedible leaves, garden waste, and unrecycled paper or cardboard. Used to make bags, containers, cutlery, water and shampoo bottles, this bioplastic is compostable, marine degradable (meaning that if it ends up in the ocean, it can serve as fish or bacteria food) and has no toxic effects. Full Cycle can process the PHA at the end of its life, and use it to make virgin plastic again.
Pennsylvania-based Renmatix is utilizing woody biomass, energy grasses and crop residue instead of costlier food crops. Its technology separates sugars from the biomass using water and heat instead of acids, solvents or enzymes in a comparatively clean, quick and inexpensive process. Both the sugars and the lignin from the biomass are then used as building blocks for bioplastics and other bioproducts.
At Michigan State University, scientists are trying to cut production costs for bioplastic through the use of cyanobacteria, also known as blue-green algae, that use sunlight to produce chemical compounds through photosynthesis. Instead of feeding their plastic-producing bacteria sugars from corn or sugarcane, these scientists tweaked cyanos to constantly excrete the sugar that they naturally produce. The plastic-producing bacteria then consume the sugar produced by the cyanos, which are reusable.
Cyanobacteria can be used to feed the microbes that create bioplastic. Photo: DBCLSStanford University researchers and California-based startup Mango Materials are transforming methane gas from wastewater treatment plants or landfills into bioplastic. The methane is fed to plastic-producing bacteria that transform it into PHA, which the company sells to plastic producers. It is used for plastic caps, shampoo bottles or biopolyester fibers that can be combined with natural materials for clothing. The bioplastic will biodegrade back into methane, and if it reaches the ocean, can be digested naturally by marine microorganisms.
The Centre for Sustainable Technologies at the University of Bath in England is making polycarbonate from sugars and carbon dioxide for use in bottles, lenses and coatings for phones and DVDs. Traditional polycarbonate plastic is made using BPA (banned from use in baby bottles) and the toxic chemical phosgene. The Bath researchers have found a cheaper and safer way to do it by adding carbon dioxide to the sugars at room temperature. Soil bacteria can break the bioplastic down into carbon dioxide and sugar.
Ecovative packaging made of mycelium aims to replace plastic altogether. Photo: mycobondAnd then there are those developing innovative ways to replace plastic altogether. Japanese design company AMAM is producing packaging materials made from the agar in red marine algae. The U.S. Department of Agriculture is developing a biodegradable and edible film from the milk protein casein to wrap food in; it is 500 times better at keeping food fresh than traditional plastic film. And New York-based Ecovative is using mycelium, the vegetative branching part of a fungus, to make Mushroom Materials, for biodegradable packaging material, tiles, planters and more.
Right now, it's hard to claim that bioplastics are more environmentally friendly than traditional plastics when all aspects of their life cycle are considered: land use, pesticides and herbicides, energy consumption, water use, greenhouse gas and methane emissions, biodegradability, recyclability and more. But as researchers around the world work to develop greener varieties and more efficient production processes, bioplastics do hold promise to help lessen plastic pollution and reduce our carbon footprint.
Plastic litter pollution in the oceans is increasingly emerging as a serious global environmental concern. Since , approximately 8.3 billion tons of plastic have been produced, with an estimated 6.3 billion tons disposed of as waste. Notably, ocean plastic litter stemming from discarded plastic containers washed into the sea has gradually deteriorated, fragmenting into microplastics. This process causes ecological and marine environmental degradation, garnering widespread attention.
"Biodegradable plastics" have been proposed as a potential solution to the aforementioned plastic waste dilemma.
This article delves into the technology, benefits, and drawbacks of biodegradable plastics.
*Information accurate as of September .
Biodegradable plastics are plastics that degrade under specific conditions after use. They can be handled similarly to general plastic products, but after use, they degrade at the molecular level through the action of microorganisms present in the natural environment, ultimately transforming into carbon dioxide (CO2) and water (H2O).
Biodegradable plastics can be categorized into three groups based on raw materials and manufacturing methods. The details are outlined below.
'Microbially produced: Biodegradable plastics are manufactured utilizing microorganisms.
'Natural extracted: Derived from cellulose found in plants, corn, other grains, potatoes, and similar sources.
'Chemically synthesized: Produced through chemosynthetic reactions.
The following are examples of substances in "biodegradable plastics" based on the aforementioned classification.
The company is the world’s best biodegradable plastic film manufacturer supplier. We are your one-stop shop for all needs. Our staff are highly-specialized and will help you find the product you need.
Table 1: Representative examples of biodegradable plastics
(Reference source: National Institute for Environmental Studies)
Among the representative substances, the following provides an overview of the four substances that have garnered attention (highlighted in yellow in Table 1).
Polyhydroxyalkanoates (PHAs) are storage compounds that accumulate in the bodies of various microorganisms.
PHA is produced through bacterial fermentation processes using vegetable oils and other raw materials.
After use, PHA undergoes rapid degradation in soil and seawater, converting into water and CO2. Thus, PHA is anticipated to replace plastics derived from fossil fuels.
Given PHA's brittleness, polyesters copolymerized with monomers have been developed to enhance strength, serving as raw materials for rigid injection-molded products and films.
Polylactic acid (PLA) is synthesized through a polymerization reaction of L-lactic acid, obtained via starch fermentation.
Corn-derived starch is commonly utilized as a raw material. This starch undergoes enzymatic hydrolysis and fermentation to yield L-lactic acid, which is then subjected to chemical polymerization to form polylactic acid.
While biodegradable, PLA exhibits slow decomposition under standard conditions and breaks down gradually in soil or water. However, in composting facilities, it decomposes almost entirely within approximately six months.
Due to its low heat resistance and transparency, PLA finds applications as packaging material for frozen foods, plastic bags, agricultural sheeting, and greenhouse films.
Polybutylene succinate (PBS) is a polymer compound possessing excellent properties akin to polyethylene.
Technology has been developed to manufacture it from biomass materials, and it is garnering attention as a promising biodegradable plastic.
Applications incorporating it include agricultural mulch film, garbage bags, and food packaging materials.
Polycaprolactone (PCL) is a biodegradable plastic synthesized from petroleum-derived raw materials and degraded by bacteria.
Leveraging its low melting point and thermoplastic properties, PCL finds use in agricultural mulch film, compost bags, as well as in paints and fibers.
Biodegradable plastics offer significant environmental benefits due to their ability to decompose naturally through the action of microorganisms, ultimately breaking down into water and carbon dioxide. This decomposition is especially effective in compost systems, where these plastics contribute to the production of high-quality organic fertilizer without negatively impacting its quality. Additionally, when incinerated, biodegradable plastics have a low calorific value, which prevents damage to incinerators and minimizes atmospheric pollution. These characteristics make biodegradable plastics ideal for products used in natural settings or in applications where recycling is challenging.
The following table summarizes the fields and applications where biodegradable plastics find utility.
Table 2: Fields where biodegradable plastics are used
Source: Green Japan (partially quoted and reconstructed from data)
Biodegradable plastics decompose in environments such as soil or water, or in compost. In other words, creating an environment conducive to microbial activity is crucial for plastics to decompose effectively.
Biodegradable plastic agricultural mulch film typically takes several months or longer to decompose, while biodegradable plastic garbage bags break down into smaller pieces more quickly.
The rate of degradation of biodegradable plastics is highly reliant on microbial activity and the surrounding environment.
Biodegradable plastics generally incur higher production costs compared to conventional plastics. This is due to the labor-intensive development and production processes. Additionally, the utilization of plant-derived raw materials increases raw material costs in contrast to fossil fuels (e.g., petroleum).
While biodegradable plastics naturally degrade, the recycling process to reuse them as recycled resin may become challenging.
In particular, if marine biodegradable plastics* become predominant in the future, reusing them may become challenging, leading to a higher proportion being sent to landfills or incinerated, potentially impacting the recycling system.
*Marine biodegradable plastics: Plastics that are degraded in the ocean by the action of enzymes produced by microorganisms.
Biodegradable plastic snack food packaging labeled as "compostable" has sparked consumer complaints.
The "100% compostable package" faced criticism from users due to the bag wrinkling and emitting a loud noise when snacks were removed. Eventually, the manufacturer introduced a different biodegradable product that was "quieter," resolving the issue.
These early efforts in using biodegradable plastics underscore the importance of "anticipating and addressing new challenges proactively from the consumer's perspective."
Addressing environmental concerns in plastic waste involves promoting biodegradable plastics, biomass plastics, and material recycling with mono-materials. The benefits are as follows.
Biodegradable plastics possess the ability to decompose in the natural environment, reverting to soil and seawater. Conversely, biomass plastics utilize renewable organic resources like plants as raw materials, reducing reliance on fossil fuels such as petroleum. Moreover, the adoption of "mono-materials" facilitates efficient material recycling, contributing to the realization of a circular economy.
Below is an in-depth overview of the current challenges and strategies for the three initiatives.
There are four major challenges to the widespread use of biodegradable plastics:
1. Technical issues in biodegradable plastics manufacturing
2. Establishment of evaluation and certification systems for manufactured products
3. Development of composting facilities
4. Reduction of production costs
Currently, only about seven types of biodegradable plastics are in practical use (refer to Table 1), necessitating ongoing development of new plastics that match the functions and performance of fossil fuel-based counterparts.
Establishing test methods to evaluate biodegradability and ensuring safety evaluation methods are essential. However, the presence of multiple standards and specifications for biodegradable plastics in Japan warrants attention. Additionally, the lack of consumer awareness leads to the improper disposal of biodegradable plastics mixed with regular plastic collection.
In Japan, the Japan BioPlastics Association (JBPA) was founded in with the objective of advancing and commercializing biodegradable plastic technology.
The JBPA has instituted the "Green Plastic Identification and Labeling System" to authenticate biodegradability and safety. Products meeting the JBPA's screening criteria are permitted to display the "Biodegradable Plastic" mark.
Various standards for biodegradable plastic test methods have been established in the Japanese Industrial Standards (JIS), while the International Organization for Standardization (ISO) oversees standards abroad.
Other initiatives to promote dissemination include "expanding composting facilities" and "achieving cost reduction through economies of scale," which serve as focal points for future enhancements.
"Biomass plastic" refers to plastic derived from plant-based materials. Originally, it was categorized as carbon-neutral because it utilizes plant-derived materials (plants absorb CO2 and water for growth), thereby not contributing to the increase in CO2 concentration in the atmosphere.
To encourage the adoption of biomass plastics, the Japanese government ratified the Kyoto Protocol in June , followed by the announcement of the "Biomass Nippon Strategy" in the same year. Subsequently, in , it formulated a "Roadmap for Bioplastics Introduction" and is actively promoting the implementation of measures among bioplastics manufacturers, users, retail service providers, and others.
The following four issues need to be addressed to promote the use of biomass plastics:
1. Higher price compared to materials derived from fossil fuels (e.g., petroleum).
2. Some biomass plastics do not biodegrade.
3. Certain biodegradable biomass plastics, assumed to degrade on the ground by microorganisms, do not easily degrade in the ocean.
4. The raw materials for biomass plastics are crops such as sugarcane and corn, so increasing production for bioplastics will impact sales of food crops.
Solutions to the above issues need to be presented systematically in the future.
The "Strategy for Strengthening Material Innovation Capabilities," formulated by the Japanese government on April 27, , sets the following goals to realize a circular economy:
1. Effectively use 100% of used plastics through reuse and recycling by
2. Introduce approximately 2 million tons of biomass plastic by
Specific efforts to achieve these goals are outlined as follows:
'Establishment of materials and product design technology (mono-materials) based on reuse and recycling, and formulation of product design guidelines
'Improvement of efficiency and sophistication of material recycling and chemical recycling technologies to achieve compatibility with carbon neutrality
Thus, "material recycling through mono-material" aligns with government policy.
DNP's mono-materials technology boasts two key features. Firstly, the materials are designed for easy recycling, reducing recycling burdens and enhancing the quality of recycled materials.
Secondly, they offer superior protection for the contents of product packages. DNP's mono-material packaging materials utilize proprietary converting technology to replace conventional composite materials.
DNP offers mono-material packaging materials in two types: PE (polyethylene) and PP (polypropylene). Depending on the intended use, they can be utilized for products such as pouches and tube containers.
Contact us to discuss your requirements of biobag dog poop bags. Our experienced sales team can help you identify the options that best suit your needs.