Polyhydroxybutyrates (PHBs): an eco-friendly alternative to petroleum-based plastics for diminution of their detrimental effects on the environment

Human has been known to use different types of polymers in their daily routine for ages, among which plastics that are derived from fossil fuels or petroleum occupies a greater part. The domestic, as well as commercial use of plastics, has been known so far globally. Plastics are used for packaging, making utensils, household items, portable machines, spare parts, medical stents, spectacles, sportswear, cellphones, golf balls and many other items. Despite knowing the negative and fatalistic effects of plastics, we humans have become dependent on plastics for our daily routine welfare. The major reasons for this are durability, inertness, lightweight, thermal and electrical insulation, resilience to corrosion and readily moulding into multifarious shapes. But the non-biodegradability of this polymer has led to many environmental issues that have detrimental effects. So there is a need to switch from non-biodegradable plastics to biodegradable ones to reduce these harmful effects without the replacement of other properties of petroleum-based plastics that makes it one of the most commercially used polymer. Biodegradable plastics have gained a lot of attention over a shorter period. These include Polyhydroxybutyrates (PHBs) and Polyhydroxyalkanoates (PHAs) majorly. These are biodegradable along with all the properties that petroleum-derived plastics have which makes them a finer and eco-friendly option. The present review focuses majorly on PHBs and summarises their physical properties, biosynthesis and different methods of industrial production, extraction, PHB-based biocomposites and/or nanocomposites along with their applications and prospects.