Switching from petro-plastics to microbial polyhydroxyalkanoates (PHA): the biotechnological escape route of choice out of the plastic predicament? (original) (raw)
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Bacterially Produced Polyhydroxyalkanoate (PHA): Converting Renewable Resources into Bioplastics
Dependence on conventional plastics and their boundless usage have resulted in waste accumulation and greenhouse gas emissions. Recent technologies are directed towards the development of bio-green materials that exert negligible sideeffects on the environment. A biologically-synthesized plastic, polyhydroxyalkanoate (PHA), has been attracting major interests due to its similar physical properties to synthetic plastics. Unlike synthetic plastics, PHA is produced from renewable resources and is degraded aerobically by microorganisms to CO 2 and H 2 O upon disposal. The selections of suitable bacterial strains, inexpensive carbon sources, efficient fermentation and recovery processes are important aspects that should be taken into consideration for the commercialization of PHA. This chapter discusses economical strategies to reduce production costs of PHA as well as its applications in various fields.
MOJ Applied Bionics and Biomechanics
Millions of tons of chemical plastics are accumulated annually worldwide in terrestrial and marine environments due to inadequate recycling plants and facilities and low circular use. Their continuous accumulation and contamination of soil and water pose a severe threat to the environment and to human, animal and plant health. There is therefore an urgent need to develop effective eco-environmental strategies to overcome the significant environmental impacts of traditional plastic waste management practises (incineration, landfilling, and recycling). In recent years, reports on microbial strains equipped with the potential of degrading plastic materials, which can further be converted into usable products such as PHA bioplastics have sprung up, and these offer a possibility to develop microbial and enzymatic technologies for plastic waste treatment and then progressing plastics circularity. In this chapter, an overview of the reported microbial and enzymatic degradations of petroleu...
Waste to bioplastics: How close are we to sustainable polyhydroxyalkanoates production?
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Increased awareness of environmental sustainability with associated strict environmental regulations has incentivized the pursuit of novel materials to replace conventional petroleum-derived plastics. Polyhydroxyalkanoates (PHAs) are appealing intracellular biopolymers and have drawn significant attention as a viable alternative to petrochemical based plastics not only due to their comparable physiochemical properties but also, their outstanding characteristics such as biodegradability and biocompatibility. This review provides a comprehensive overview of the recent developments on the involved PHA producer microorganisms, production process from different waste streams by both pure and mixed microbial cultures (MMCs). Bio-based PHA production, particularly using cheap carbon sources with MMCs, is getting more attention. The main bottlenecks are the low production yield and the inconsistency of the biopolymers. Bioaugmentation and metabolic engineering together with cost effective downstream processing are promising approaches to overcome the hurdles of commercial PHA production from waste streams.
Bacterial polyhydroxyalkanoates: Opportunities, challenges, and prospects
Journal of Cleaner Production, 2020
Excessive utilization of synthetic plastics has led to a major detrimental impact on the environment. Plastic pollution and accumulation in water bodies have threatened the survival of marine life. Plastic pollution can be prevented by using biopolymers that are eco-friendly and can be naturally produced by certain living organisms. The biopolymers have environmental advantages over synthetic plastics, such as biodegradability and biocompatibility. In comparison to plants and other microbial systems, bacteria can accumulate a high amount of polyhydroxyalkanoates (PHAs). However, the major stumbling block in the production of bacterial PHAs is its low cost-effectiveness due to costs associated with fermentaion and down-stream processing. In consideration with the above properties, opportunities and challeges associated with bacterial PHAs, this review focuses on structural diversity of PHAs, biosynthesis mechanism in bacteria, biodegradation, life cycle analysis, and environmental impact of bioplastic production. It further enumerates the advanced tools and techniques for bacterial PHA production, along with various factors affecting the commercialization of bioplastics. Extraction methods, down-stream processing, and biomedical applications of PHAs are also discussed. The opportunities and challenges in the commercialization of bacterial PHAs along with future scenario and environmental sustainability are presented for the purpose of fostering sustainable development.
Microbial Production of Bioplastics: An Eco-friendly Alternative
Ecology, Environment and Conservation
Accumulation of non-biodegradable plastic has shown adverse impacts on the environment and calls for a dire need for a sustainable alternative. Various microbial strains can produce bioplastics in the form of Polyhydroxyalkanoates (PHAs) as energy reserves. Many bacteria, fungi and microalgae have been studied to produce such biopolymers. PHAs are biodegradable and meet the basic requirements of life cycle environmental impact or life cycle assessments for proper disposal. They are also biocompatible and renewable. They have high Elastic modulus, Tensile modulus, melting temperature, and crystallinity with many other properties similar to synthetic plastics currently in use, making them a more reliable and sustainable substitute. Bioplastics produced from PHAs have found a myriad of applications in medicine, pharmaceuticals, agriculture and the packaging industry. This review emphasizes the structure of PHAs, their biosynthesis and relevant microbial strains employed, including gene...
Production of Polyhydroxyalkanoates, a bacterial biodegradable polymer
African Journal of Biotechnology, 2004
There has been considerable interest in the development and production of biodegradable polymer to solve the current problem of pollution caused by the continuous use of synthetic polymer of petroleum origin. Polyhydroxyalkanoates (PHAs) are known to be accumulated as intracellular inclusion in some bacteria. The materials properties exhibited by PHAs, ranging from stiff, brittle to rubber-like makes it a close substitute for the synthetic plastic. The high cost of PHAs production has restricted its applications. The possibility of producing this polymer commercially and at comparable cost has been the main focus in this area.
Polyhydroxyalkanoates – Linking Properties, Applications and End-of-life Options
Chemical & biochemical engineering quarterly, 2020
When it comes to “bioplastics”, we currently notice an immense complexity of this topic, and, most of all, a plethora of contradictory legislations, which confuses or even misleads insufficiently informed consumers. The present article therefore showcases microbial polyhydroxyalkanoate (PHA) biopolyesters as the prime class of “bioplastics” sensu stricto. In particular, biodegradability of PHA as its central benefit in elevating the current plastic waste scenario is elaborated on the biochemical basis: this covers aspects of the enzymatic machinery involved both in intra- and extracellular PHA degradation, and environmental factors impacting biodegradability. Importantly, PHA degradability is contextualized with potential fields of application of these materials. It is further shown how the particularities of PHA in terms of feedstocks, mode of synthesis, degradability, and compostability differ from other polymeric materials sold as “bioplastics”, highlighting the unique selling po...