Plastics have become one of the backbones of the global economy and have grown to be one of the world's largest material commodities aside from cement and steel. Plastic as a material has constantly grown inseparable from human day-to-day activity. Plastic production began in the early 20th century and was mainly used in military applications. Beyond World War II utilization of synthetic plastic was adopted for non-military applications and productions in the 1950s were recorded at 2 million tons/year, which since then has leapt to 348 million tons in 2017 and 359 million tons (MT) in 2018 [1], [2]. China is the world's largest plastic producer (29.4%) followed by Europe (18.5%) and the United States at 17.7%, as shown in Fig. 1 [1], [2].

The largest application of plastic is in the packaging industry. Up to 30% of global production of plastic is in the packaging industry. Expansive growth in plastic for packaging was due to the worldwide shift from reusable packaging to single-use (disposable) packaging, causing the explosion in plastic waste worldwide, overflowing and accumulating in landfills, major water basins, and almost every natural environment [1], [3].

The global plastic pollution in the majority would ultimately find its way into the oceans. Out of the 359MT of plastics produced in 2018 [2] and the huge leap up to 415MT reported in 2019, 3% would end up finding its way to leak into the ocean and marine environments [4]. Even with plastic wastes that accumulated in landfills, leakage would still find its way to the water system and finally to the ocean [1], [3], with which global leakage would be expected at 3% or estimated at 10MT/year (Fig. 2.). Given that approximately 32% of single-use (disposable) plastics escape the collection systems, the estimates would be even higher [4].

Plastics polluting the ocean and marine environment can be categorized into 2 major categories: macroplastics (large plastic wastes as originally manufactured-sized plastics finding its way to the ocean) and microplastics (small particles less than 5 mm in size). Microplastics are then further divided into 2 categories as primary microplastics (directly released to the environment i.e.: rain washed tire erosions from automobiles or fabric abrasions from the washing of synthetic textiles), and secondary microplastics as in the particle fragments of larger plastics degraded by weathering, microbial degradation and photodegradation into the environment [1], [4], [5], [6], [7].

Degradation of plastic would yield smaller plastic particles ranging from size (mesoplastics, microplastics, and nanoplastics), further degradation will break down these particles to their basic monomers. Monomers of plastics like ethylene and propylene are fossil-based hydrocarbons that are in majority not biodegradable, therefore would accumulate and not decompose. Only pyrolysis and other destructive thermal methods would successfully eliminate plastic wastes permanently. Although many pyrolysis and incineration techniques are developed to account for this problem, any thermal destruction process would have ramifications to health, emission, carbon footprint and energy issues. Thus, the likelihood is that plastics are mainly discarded as are contained in a managed landfill or left uncontained in dumps or the environment [1]. This contamination of plastics eventually will reach levels which will have effects on the food chain and the well-being of mankind in this current decade to come [5].

Abiotic environmental degradation has resulted in the fragmentation of the larger macroplastics to secondary microplastics and leached micro- & nano plastic contamination into the environment, but the microbiotic roles in this process to date are still poorly understood. Although there have been reports of occurrences of microbial depolymerization of synthetic polymers and petroleum plastics such as polyethylene and polystyrene, the process is very slow. While the key depolymerase involved in the breakdown of the carbon backbone of this process is still unknown [4], [7]. A study was carried out to observe the microbial degradation of polyethylene in a controlled environment. The biodegradation process of the polyethylene sheets by Enterococcus cloacea and a mixed population of soil-isolated bacteria was observed in an incubation of 370C for 30 days which the Scanning Electron Microscope (SEM) results indicated the occurrence of biodegradation of some portions of the polyethylene sheet. However, the study indicated that bacteria took a long time to degrade plastics [8].

The durability of petroleum plastic materials to various physical, chemical, and biological factors as well as their hydrophobic properties, degree of crystallinity, surface topography and molecular size limits the biodegradability to an extremely slow degradation process [4], [7], [9]. Adsorption and catalytic performances by degrading enzymes have been limited by the hydrophobic surface, which along with the smooth surface topography and low surface-to-volume ratio are limiting the formation of biofilm by the biodegrading bacteria, causing the need to pretreat the plastic materials to improve the surface area to volume ratio that in the end to allow surface area access for bacteria and enzymes to commence degradation. Also, note the role of the strong and stable Carbon-to-Carbon (C-C) bonds which are required to be oxidized prior to any depolymerization and defragmentation process to occur. This array of pretreatments renders the process of biocatalytic recycling of plastic materials to be impeded by economic costs [9] which would cost more than to produce the plastic materials, to begin with. Progress has been made in the applications of biocatalytic recycling of plastics and metagenomic approaches and evolution strategies have been directed to identifying mutations of polyester complementing enzyme microbial variants as the key challenge. In the meantime, the accumulation of petroleum plastics continues to pollute the environment and secondary microplastics impose an even more serious impact by leaching its way into the food chains when ingested by marine life [4], [9]. Therefore, bioplastics or plastic that are derived from renewable source materials such as natural polymers of starch, lignocellulosic materials or proteins is presented as a probable alternative solution to the heavily toxic petroleum plastic.