2
1.1 Introduction
Plastic discovered as a material element has revolutionized many sectors due to their
application versatility (Singh et al. 2011). These synthetic polymers from the petroleum fraction have replaced many natural materials used before their discovery; however, their recalcitrant nature resulted in long persistence in the environment that
ended up in landfilling and burning; as well seepage in different ecosystems has now
become a global concern (Thompson et al. 2009a; Goudie 2018). These wastes act as
key indicators of human activity (Rochman 2015; Zalasiewicz et al. 2016). Industrial
development and increased population are the foremost contributors to plastic waste
generation (Singh et al. 2011). The traditional plastic waste management system
includes landfilling, burning, and recycling, resulting in infertile land and toxic
chemical evolution in the environment. Only around 15–25% of the plastic waste is
recycled in Europe and recycling below 5% in the USA, although the remaining persist as such in the environment (Barnes et al. 2009). Globally, 8% of the petroleum
fraction is used to produce plastic, where 4% used as raw material and 4% in the
energy required for production (Hopewell et al. 2009; Thompson et al. 2009a). The
major proportion of plastics is used in packaging, which is often discarded rapidly,
which creates an unsustainable situation and demands control measures.
To decrease the plastic discards in the environment, the alternative approaches
are to produce biodegradable plastics and to isolate microbes from the environment
that are capable to degrade plastics (Wierckx et al. 2015; Kumari et al. 2019; Kawai
et al. 2019). Many biodegradable and bio-based polymers have been developed, but
complete replacement of plastic is impossible due to their high production cost and
application limitations. Besides this, microbial degradation of the synthetic polymer
will be innovative to the world; however, the efficiency of this eco-friendly measure
for reducing plastic waste is questionable (Tolinski 2011). In nature, the process of
biodegradation is continuously occurring to maintain planet sustainability. However,
the rate of waste production is much higher than that of natural degradation
processes.
Bioremediation technology will provide a sustainable solution for rising plastic
waste in the environment. The research on bioremediation studies is developing,
and many enzymes from microbes are capable of destabilizing and degrading recalcitrant synthetic plastics (Bhardwaj et al. 2013; Wei and Zimmermann 2017; Kumari
et al. 2017). Microbial enzymes are developing as biocatalytic agents for the remediation and recycling processes of plastics, by which valued raw materials can be
recovered and produced (Araújo et al. 2007). Microbial plastic degradation will be
an eco-friendly approach for reducing plastic waste as well as a solution to the distressing situation due to plastic waste generation (Devi et al. 2016).
To date, no feasible biodegradation processes have been developed that can be
used on a large scale. Research advancement in the genomics and metabolomics
area concords to cognize the microbial ability to degrade polymeric wastes and
predict degradation pathways (Dvořák et al. 2017). Here, recent findings and possible plastic waste remediation strategies have been summarized, and future
A. Kumari et al.
1.1 Introduction
Plastic discovered as a material element has revolutionized many sectors due to their
application versatility (Singh et al. 2011). These synthetic polymers from the petroleum fraction have replaced many natural materials used before their discovery; however, their recalcitrant nature resulted in long persistence in the environment that
ended up in landfilling and burning; as well seepage in different ecosystems has now
become a global concern (Thompson et al. 2009a; Goudie 2018). These wastes act as
key indicators of human activity (Rochman 2015; Zalasiewicz et al. 2016). Industrial
development and increased population are the foremost contributors to plastic waste
generation (Singh et al. 2011). The traditional plastic waste management system
includes landfilling, burning, and recycling, resulting in infertile land and toxic
chemical evolution in the environment. Only around 15–25% of the plastic waste is
recycled in Europe and recycling below 5% in the USA, although the remaining persist as such in the environment (Barnes et al. 2009). Globally, 8% of the petroleum
fraction is used to produce plastic, where 4% used as raw material and 4% in the
energy required for production (Hopewell et al. 2009; Thompson et al. 2009a). The
major proportion of plastics is used in packaging, which is often discarded rapidly,
which creates an unsustainable situation and demands control measures.
To decrease the plastic discards in the environment, the alternative approaches
are to produce biodegradable plastics and to isolate microbes from the environment
that are capable to degrade plastics (Wierckx et al. 2015; Kumari et al. 2019; Kawai
et al. 2019). Many biodegradable and bio-based polymers have been developed, but
complete replacement of plastic is impossible due to their high production cost and
application limitations. Besides this, microbial degradation of the synthetic polymer
will be innovative to the world; however, the efficiency of this eco-friendly measure
for reducing plastic waste is questionable (Tolinski 2011). In nature, the process of
biodegradation is continuously occurring to maintain planet sustainability. However,
the rate of waste production is much higher than that of natural degradation
processes.
Bioremediation technology will provide a sustainable solution for rising plastic
waste in the environment. The research on bioremediation studies is developing,
and many enzymes from microbes are capable of destabilizing and degrading recalcitrant synthetic plastics (Bhardwaj et al. 2013; Wei and Zimmermann 2017; Kumari
et al. 2017). Microbial enzymes are developing as biocatalytic agents for the remediation and recycling processes of plastics, by which valued raw materials can be
recovered and produced (Araújo et al. 2007). Microbial plastic degradation will be
an eco-friendly approach for reducing plastic waste as well as a solution to the distressing situation due to plastic waste generation (Devi et al. 2016).
To date, no feasible biodegradation processes have been developed that can be
used on a large scale. Research advancement in the genomics and metabolomics
area concords to cognize the microbial ability to degrade polymeric wastes and
predict degradation pathways (Dvořák et al. 2017). Here, recent findings and possible plastic waste remediation strategies have been summarized, and future
A. Kumari et al.