Current Scenario of Packaging Material
Packaging is an essential aspect in protecting the food item from contamination as well as maintaining the quality of the product. As packaging material, plastic is the most exploited material in the world because of its durability, easy availability, and high mechanical strength. But due to non-degradability in the environment, plastic waste becomes the biggest problem in front of the world. According to the United Nations Environment Programme 2021, every year around 46% of plastic waste comes from packaging. The Ministry of Environment, Forest and Climate Change, India reported that 2.26 million tonnes of plastic waste was generated in the form of packaging material. Other countries also have similar figures of plastic waste generation as packaging waste. The generation of a high amount of packaging plastic waste is creating a big challenge of disposal. However, unfortunately, the world does not have any proper disposal technique for plastic in the environment, which makes it the biggest problem in the current scenario.
Plastic waste has very serious negative impacts on the environment, including soil contamination, loss of biodiversity, water pollution, release of greenhouse gases, and negative health impacts on humans, animals, and marine life.
Bio-plastic — Polyhydroxybutarate (PHB): a New-age Solution in Packaging System
PHB is a foremost member of the polyhydroxyalkanoate family, having excellent biodegradability and biocompatibility. The very first PHB was synthesized in the year 1970; thereafter, the work on PHB was extensively performed for the synthesis of PHB because of durability and acceptability similar to conventional plastics. PHB can be produced by microbial fermentation of renewable sources including sugar, starch, and vegetable oils, etc. PHB can be synthesized by both Gram-positive as well as Gram-negative bacteria under nutrient-limiting conditions with excess carbon sources and controlled amounts of oxygen, sulphur, nitrogen, and phosphorus compounds. PHB is a thermoplastic polymer that exhibits properties like good toughness, less crystalline structure, and higher melting temperature, similar to polypropylene, making it suitable for a wide range of applications including packaging.
Production of PHB: Essential Microbial Source and Substrates
PHB is used to be produced by the microbial fermentation technique. The specific microbes are present which are capable to produce PHB. In this technique, the PHB is produced by the bacteria intracellularly using the substrate as a carbon source. The production of PHB depends on various factors including microbial strain, substrate, and growth conditions. A variety of bacterial strains including Cupriavidus necator, Cupriavidus necator H16, Cupriavidus necator DSM 545, Cupriavidus necator DSM 428, Bacillus sp. ISTVK1, Cupriavidus necator H16, Bacillus safensis EBT1, Ralstonia eutropha, Ralstonia eutropha, Bacillus strain, Cupriavidus necator CCGUG 52,238, Haloferax mediterranei, Pseudomonas mendocina PSU, Bacillus megaterium, Wautersia eutropha, Cupriavidus sp. KKU38, etc., are reported in various research articles for the production of PHB. Among these bacterial strains, Cupriavidus necator is extensively used for the production of PHB at an industrial scale because of its High PHB Accumulation, Fast Growth Rate, Utilization of Diverse Carbon Sources, Genetic Stability, and Commercial Feasibility.
Substrate for carbon source plays a significant role in the growth of micro-organisms. For PHB production, various types of substrates have been used including renewable resources (e.g., starch, cellulose, sucrose), waste materials (molasses, whey, glycerol), and chemicals such as propionic acid. In current research for PHB production, the focus is mainly on the identification of affordable and easily available substrates with high yield of PHB so that the production can be increased and make the PHB available at every level of the society. To fulfil the purpose, the cheap production of PHB is required and waste materials are now used as substrate material for PHB-producing bacterial strains such as lignocellulosic material from agricultural crops and forestry waste, sucrose-based material from by-products in the sugar production industries (sugarcane molasses), by-products of dairy industries, oil, fatty acids, glycerol-based waste material, agro-industrial waste and by-products, etc.
Current Challenges for PHB Production
Extensive research on PHB production has been done but still several challenges have been taken into account by researchers to conduct more research to solve the following:
- PHB production cost is comparatively higher than the general-use plastic, which ultimately increases the cost of PHB. To reduce the production cost is still a challenge.
- PHB is a brittle material, which confines the application area. Introduction of flexibility can expand the usage of PHB in all possible fields.
- PHB is still in research and is highly recommended to transfer it from laboratory to industry, which is still a challenge because without applicability at industrial scale, the elimination of conventional plastic by the bio-plastic (PHB) is not possible.
To overcome these challenges, ongoing research is focused on improving PHB properties through copolymerization, blending with other biopolymers, and optimizing microbial fermentation processes. Government policies promoting biodegradable materials, coupled with consumer awareness, are also expected to drive the growth of PHB-based packaging in the future.
In conclusion, conventional plastic waste is one of the biggest problems of the current society, and biodegradable PHB can be the most successful way to fight with it. It can help to maintain the environmental pollution level in the world. The technological development can help to overcome the challenges associated with PHB production, especially using cost-effective processes and substrates. The affordable production can make PHB available at the ground level for packaging applications and will help in creating a plastic-free, greener, and highly sustainable future.
References
- Thulasisingh, Anitha, Krishnapriya Kumar, B. Yamunadevi, N. Poojitha, S. SuhailMadharHanif, and Sathishkumar Kannaiyan. "Biodegradable packaging materials." Polymer Bulletin 79, no. 7 (2022): 4467-4496.
- Phelan, Anna Anya, Katie Meissner, Jacquelyn Humphrey, and Helen Ross. "Plastic pollution and packaging: Corporate commitments and actions from the food and beverage sector." Journal of Cleaner Production 331 (2022): 129827.
- Ministry of Environment, Forest and Climate Change, India
- Jiang, Boyu, Jiming Yu, and Yihang Liu. "The environmental impact of plastic waste." Journal of Environmental & Earth Sciences 2, no. 2 (2020).
- Sirohi, Ranjna, Jai Prakash Pandey, Vivek Kumar Gaur, Edgard Gnansounou, and Raveendran Sindhu. "Critical overview of biomass feedstocks as sustainable substrates for the production of polyhydroxybutyrate (PHB)." Bioresource Technology 311 (2020): 123536.
Authors:
Dr. Amit Kumar Singh & Dr. Latika P. Shendre
Assistant Professors, Dr. D. Y. Patil Biotechnology and Bioinformatics Institute,
Dr. D. Y. Patil Vidyapeeth, Tathawade, Pune - 411033, Maharashtra, India.
Email: amit.singh@dpu.edu.in , latika.shendre@dpu.edu.in