A Study of Polyhydroxyalkanoates (PHA) Based Bioplastics for Sustainable Reduction of Plastic Waste.

Plastic is one of the fastest growing pollutants in the world. In a report published by Niti Aayog on Alternative Products and Technologies to Plastic and their Applications May 2022 , globally, between 10-60% of plastic waste gets recycled across different countries; it averages 30% in most countries in the EU and only about 10% in the US. Additionally, in many developed nations, a larger fraction of plastics waste gets thermally treated to recover energy as opposed getting recycled for material recovery.

Norway is the world leader in recycling plastic bottles, due to its refundable deposit program. Through this system, 97% of all plastic bottles in this Scandinavian country are recycled, making Norway the highest recycling country for plastic. Of that, 92% is turned back into bottles.

Recycling Rate: Is It Really 84%? The official “recycling rate” of end-of-life plastics in Japan is 84%. For instance, in Japan, Sweden, and Denmark, thermal treatment covers 56%, 81.7%, and 57.1% of the total plastic waste generated, respectively. However, material recycling of plastics tends to reduce the environmental footprint of plastic use and consumption significantly with a study estimating that we save approximately 3.8 barrels of petroleum by recycling a tonne of plastic waste, thereby reducing our reliance on fossil fuels18.

India ranks as the fifth-highest country in the generation of plastic waste with an annual discharge of 3.5 million tonne in fiscal year 2020, still India does better in this aspect due to a large informal sector workforce (comprised of individual waste pickers and waste traders) making a living by collecting, sorting, recycling, and selling valuable plastic materials recovered. Approximately 60% of plastic waste gets collected for recycling and recovery in India, which is much higher than in developed countries. The way we currently design, produce and consume plastics is both unsustainable and inefficient. Tackling this issue and enhancing the sustainable production and consumption of plastics requires rethinking the way economic development is pursued.

Polyhydroxyalkanoates (PHA) is a bioplastic that are naturally or artificially accumulated as water-insoluble granules within a variety of microorganisms, subject to specific conditions. PHAs are regarded as a renewable resources-based alternative to petrochemical polymers. Polyhydroxyalkanoates (PHAs) have a number of appealing properties that make PHAs a feasible source material for bioplastics, either as a direct replacement of petroleum-derived plastics or as a blend with elements derived from natural origin, fabricated biodegradable polymers, and/or non-biodegradable polymers.

In contrast to the negative effects of disposing of plastics in landfills, PHA-based bioplastics exhibit biodegradable behavior in all anaerobic and aerobic environments as described by American Society for Testing and Materials standards and can be used to make fully compostable, soil- and marine-biodegradable goods. PHA are polymer-based products which are either biobased and/or biodegradable and in food packaging found to be more rigid and less flexible than PP . PHAs are flexible, crystalline, elastic and have thermoplastic properties. The mechanical properties of PHA like the tensile strength (40MPa), Young's modulus (3.5 GPA) are similar to synthetic plastics.

Polyhydroxyalkanoates (PHA) can be produced by various methods, including bacterial fermentation, plant-based production, and genetically engineered microorganisms. Each method has its advantages and disadvantages in terms of efficiency, scalability, and environmental impact. Here is a brief overview of each method:

Bacterial Fermentation: Bacterial fermentation is the most commonly used method for PHA production. In this method, bacteria are fed a carbon source such as glucose, which they use to produce PHA as an energy storage material. The PHA is then extracted from the bacteria and purified. Bacterial fermentation has high yield and relatively low production costs. However, it can generate a significant amount of waste and requires careful management to prevent bacterial contamination.

Polyhydroxyalkanoates (PHA) is a bioplastic that are naturally or artificially accumulated as water-insoluble granules within a variety of microorganisms, subject to specific conditions.

Plant-based Production: PHA can also be produced using plant-based sources of carbon such as sugarcane, corn, and soybeans. In this method, plants are genetically modified to produce PHA, which can then be extracted and purified. Plant-based production methods may have a lower environmental impact compared to bacterial fermentation since they use renewable resources. However, they can be more expensive and less efficient compared to bacterial fermentation.

Genetically Engineered Microorganisms: In this method, microorganisms are genetically engineered to produce PHA using a variety of carbon sources. This method has the advantage of being highly customizable, allowing researchers to tailor the production process to specific needs. However, it can be more expensive and difficult to scale up compared to bacterial fermentation.

Efficiency and scalability are important factors to consider when choosing a production method for PHA. Bacterial fermentation is currently the most widely used method due to its high yield and relatively low production costs. However, other methods such as plant-based production and genetically engineered microorganisms may become more viable as technology advances and production processes become more efficient. The cost of producing PHA-based bioplastics would be a crucial factor in determining their economic viability. The cost of production would depend on the production method used, as well as factors such as raw material costs, labor costs, and energy costs.

"Life on Land: Bioplastics can also contribute to the preservation of land ecosystems by reducing the amount of plastic waste that ends up in landfills and promoting the use of renewable resources."

The use of bioplastics can contribute to achieving several Sustainable Development Goals (SDGs) established by the United Nations. Some of the ways that bioplastics can contribute to SDGs include:

Goal 12: Responsible Consumption and Production: Bioplastics can help reduce the consumption of non-renewable resources and decrease the amount of waste generated. By using bioplastics made from renewable resources, we can promote sustainable consumption and production patterns and reduce our dependence on fossil fuels.

Goal 13: Climate Action: The production of conventional plastics is a significant contributor to greenhouse gas emissions. Bioplastics made from renewable resources can help reduce these emissions and promote a circular economy by using waste as a feedstock.

Goal 14: Life Below Water: Plastic pollution is a significant threat to marine life and ecosystems. Bioplastics that are biodegradable and compostable can help reduce the amount of plastic waste that ends up in the ocean, thereby protecting marine life.
Goal 15: Life on Land: Bioplastics can also contribute to the preservation of land ecosystems by reducing the amount of plastic waste that ends up in landfills and promoting the use of renewable resources.

Goal 9: Industry, Innovation and Infrastructure: The development of bioplastics requires innovation and investment in new technologies, which can create new opportunities for sustainable industry and infrastructure development.

The environmental impact of biodegradable food packaging when considering food waste found to be approx. 50% of the environmental impact of food packaging stems from the thrown-away food contained therein, regardless of whether the packaging is biodegradable or not. the negative environmental impacts associated with disposal of a PHA-TPS packaging in landfills with low gas capture rates (CH4 emissions from anaerobic digestion, high GWP) can be offset if the package reduces food wastage by approximately 6% .

So, industry not only needs bioplastics such as PHA instead of PP, but also novel concepts for food packaging to avoid discarding foodstuff unnecessarily by the consumers. Advantages of PHA include bio-origin (processing by microorganisms), biocompatibility, biodegradability, transformations of toxic materials by microorganisms during fermentation (halogenated derivatives, CO2), additional unique properties such as piezoelectricity, and excellent barrier properties.

There are almost more than 150 different monomers of PHA have been discovered and the number is still increasing with the introduction of new techniques like modifying natural PHA by physical or chemical techniques and genetic modification of microorganisms to synthesize PHA with particular functional group. The developments have also been made in the sustainable production of PHA in many ways such as using inexpensive carbon sources, genetic engineering techniques and using different recovery methods. Different species of bacteria and archaebacteria have been used to produce PHA in sufficient amount. New bacterial species which produce copolymers and recombinant strains have been used to produce large amount of PHA in industrial scale. Some bacterial species known for economical production of PHA are Ralstonia eutropha, Aspergillus eutrophus, Cupriavidus necator, Rhodobacter sphaeroides, Wautersia eutropha, Pseudomonas sp., and recombinant E. coli.

Legislation and penalties also influence the market tendency. In this context, two main production lines for PHA can be anticipated: 1) High-end products with distinct properties and definite purpose of utilization, for which biodegradation and biocompatibility are required as advantageous properties. Examples include drug delivery materials, tissue engineering (pharmacy, medicine), and nanobiotechnology (medicine).There is high potential for PHA polymers to replace conventional plastics used as additives and filler in cosmetics.

In such cases a higher price of PHA compared to conventional petroleum-based plastics may be acceptable. 2) Low-end products for which the circular economy is the main advantage and minor benefits may come from biodegradability, optical activity, piezoelectricity, and barrier properties. Important advantage in terms of sustainability is that the production of PHA polymers is independent of fossil resources. In the case of those produced by cyanobacteria, CO2 is absorbed and bound in the polymer . Besides application areas in which PHA polymers offer unique values include medicine, cosmetics, pharmacy, and eco-agriculture.

However, there are still some challenges to overcome before PHA bioplastics can be widely adopted. One of the biggest challenges is the cost of production, which is still higher than that of conventional plastics. There is also a need to develop better technologies for large-scale production and processing of PHA, as well as to address issues related to biodegradation and compostability in real-world conditions. Larget players in PHA are Danimer Scientific (US), Shenzhen Ecomann Biotechnology Co. Ltd. (China), Kaneka Corporation (Japan), RWDC Industries (Singapore), and TianAn Biologic Materials Co.

Overall, PHA have great potential as a sustainable alternative to conventional plastics, and continued research and development in this area could help to accelerate the adoption of PHA-based bioplastics and reduce our reliance on non-renewable resources. Governments can play a significant role in supporting the use of bioplastics by implementing policies and initiatives that promote their adoption. Here are some examples of government interventions that can support the use of bioplastics:

Incentives for businesses: Governments can provide tax incentives, subsidies, or other financial support to businesses that produce or use bioplastics. These incentives can help reduce the cost of production and encourage businesses to adopt more sustainable practices.
Regulations and standards: Governments can implement regulations and standards that require or encourage the use of bioplastics in certain industries or applications. For example, some countries have implemented bans on certain types of single-use plastics or required the use of biodegradable plastics in packaging.

Education and awareness campaigns: Governments can also play a role in educating the public about the benefits of bioplastics and promoting their use through awareness campaigns. This can help increase demand for bioplastics and encourage businesses to adopt them.

Research and development funding: Governments can provide funding for research and development of new technologies and processes to produce bioplastics more efficiently and sustainably. This can help drive innovation and make bioplastics more competitive with conventional plastics.

Procurement policies: Governments can use their purchasing power to support the use of bioplastics by requiring their suppliers to use sustainable materials, including bioplastics. This can help create a market for bioplastics and encourage their adoption by businesses.

India has taken several initiatives to promote the production of Polyhydroxyalkanoates (PHA) as a sustainable alternative to conventional plastics. Some of the notable initiatives like National Bio-Plastics Mission: In 2018, the Indian government launched the National Bio-Plastics Mission with a goal to promote the development of bio-based alternatives to conventional plastics. The mission aims to create a favorable ecosystem for the production of bio-plastics and develop a roadmap for their adoption in the country.

Research and Development: Several research institutions in India are actively engaged in developing PHA-based bioplastics. The Council of Scientific and Industrial Research (CSIR), for instance, has developed a PHA-based biodegradable plastic that can be used for packaging, disposable cutlery, and other applications. The Indian Institute of Technology (IIT) Delhi has also developed a PHA-based biodegradable plastic that can be used for packaging and other applications.

Entrepreneurship Development: The government has taken steps to promote entrepreneurship in the bioplastics sector. For instance, the Biotechnology Industry Research Assistance Council (BIRAC) has launched a program to support startups and small and medium enterprises (SMEs) in the bioplastics sector.

Collaborations and Partnerships: Several collaborations and partnerships have been formed between Indian and international organizations to promote the production of PHA. For example, a joint venture between India's Reliance Industries and Netherlands-based Neste has been established to produce bio-based raw materials for the production of plastics, including PHA.

In summary, the use of bioplastics can help to promote sustainable consumption and production patterns, reduce greenhouse gas emissions, protect marine and land ecosystems, and create new opportunities for sustainable industry and infrastructure development. government intervention can help support the use of bioplastics by providing incentives, implementing regulations and standards, educating the public, funding research and development, and using procurement policies to create a market for sustainable materials.