7
assimilate chemicals such as polyaromatic hydrocarbons, polychlorinated biphenyls, and polybrominated diphenyl ethers and suffer liver toxicity (Rochman et al.
2013). Plastic waste in the ocean also acts as a route for transporting many sessile
invasive species and spreading them to different ecosystems.
On the other hand, plastic products are mixed with additives and plasticizer to get
desirable properties such as softening, polishing, heat, and UV stabilizers that add
more to recalcitrant and toxicity. Bisphenol A and Di-(2-ethylhexyl)-phthalate are
common additives used in making plastic products where Bisphenol A is a unit of
polycarbonate plastics, where they slowly leach out over time or exposed to heat or
liquid. Numerous combinations of plastics and additives are available that mark
plastic pollutants prone to anonymous risk levels (Thompson et al. 2009a). The
chemical mixture and toxicity will vary based on the duration and environmental
exposure. These additives and plasticizers risk life to blindness, cancer, endocrine
disruption, effective reproductive system, and embryo developmental stages
(Table 1.1) as well, and disintegration into microplastics causes ingestion and accumulation in the tissues that pass through the food chain (Webb et al. 2012; Lusher
et al. 2015). Plastic-derived polybrominated diphenyl ethers are found in the
abdominal adipose tissue of seabird (Tanaka et al. 2013). Boerger et al. (2010)
reported plastic pieces in 36% of planktovorous fish with an average of 2.1 plastic
pieces found per fish from the North Pacific Central Gyre.
Rochman et al. (2015) reported that the plastic debris was found in 28% and 55%
of Indonesian fish and shellfish and in the USA 67% in fish and 33% in shellfish
sampled. The plastic consumed by aquatic organisms indirectly comes to our plate.
The subsequent plastic application in the era of modernization plastic and its additive residues definitely present in our body via direct exposure or subsequent food
webs (Andrady 2011).
1.4 Biodegradation and Natural Cycling of Plastic Waste
Biodegradation is a process of transformation or alteration of the chemical structures through the metabolic or enzymatic action of the living organism present in the
environment (United States Environmental Protection Agency 2009). The process
of biodegradation and re-mineralization of waste continuously occurs in nature to
hold onto the planet sustainability, but the rate of waste generation is much higher
than the natural cycle that takes hundreds to thousands of years to complete, therefore considered as recalcitrant material (Lardjane et al. 2013). Research interest in
biodegradation studies was started in 1982, involving classical research and facing
challenges due to technological limitations (Boopathy 2000). Studies indicate that
microorganisms act differently over different plastics (Nauendorf et al. 2016). The
indigenous microbial community and local environmental conditions play a major
role in the biodegradation rate, which determines the biogeochemical events (Sarkar
et al. 2016). Microorganisms play a major role in mediating elemental biogeochemical cycles by mineralizing the organic material into inorganic through their
1 Microbial Degradation of Plastics and Its Biotechnological Advancement
assimilate chemicals such as polyaromatic hydrocarbons, polychlorinated biphenyls, and polybrominated diphenyl ethers and suffer liver toxicity (Rochman et al.
2013). Plastic waste in the ocean also acts as a route for transporting many sessile
invasive species and spreading them to different ecosystems.
On the other hand, plastic products are mixed with additives and plasticizer to get
desirable properties such as softening, polishing, heat, and UV stabilizers that add
more to recalcitrant and toxicity. Bisphenol A and Di-(2-ethylhexyl)-phthalate are
common additives used in making plastic products where Bisphenol A is a unit of
polycarbonate plastics, where they slowly leach out over time or exposed to heat or
liquid. Numerous combinations of plastics and additives are available that mark
plastic pollutants prone to anonymous risk levels (Thompson et al. 2009a). The
chemical mixture and toxicity will vary based on the duration and environmental
exposure. These additives and plasticizers risk life to blindness, cancer, endocrine
disruption, effective reproductive system, and embryo developmental stages
(Table 1.1) as well, and disintegration into microplastics causes ingestion and accumulation in the tissues that pass through the food chain (Webb et al. 2012; Lusher
et al. 2015). Plastic-derived polybrominated diphenyl ethers are found in the
abdominal adipose tissue of seabird (Tanaka et al. 2013). Boerger et al. (2010)
reported plastic pieces in 36% of planktovorous fish with an average of 2.1 plastic
pieces found per fish from the North Pacific Central Gyre.
Rochman et al. (2015) reported that the plastic debris was found in 28% and 55%
of Indonesian fish and shellfish and in the USA 67% in fish and 33% in shellfish
sampled. The plastic consumed by aquatic organisms indirectly comes to our plate.
The subsequent plastic application in the era of modernization plastic and its additive residues definitely present in our body via direct exposure or subsequent food
webs (Andrady 2011).
1.4 Biodegradation and Natural Cycling of Plastic Waste
Biodegradation is a process of transformation or alteration of the chemical structures through the metabolic or enzymatic action of the living organism present in the
environment (United States Environmental Protection Agency 2009). The process
of biodegradation and re-mineralization of waste continuously occurs in nature to
hold onto the planet sustainability, but the rate of waste generation is much higher
than the natural cycle that takes hundreds to thousands of years to complete, therefore considered as recalcitrant material (Lardjane et al. 2013). Research interest in
biodegradation studies was started in 1982, involving classical research and facing
challenges due to technological limitations (Boopathy 2000). Studies indicate that
microorganisms act differently over different plastics (Nauendorf et al. 2016). The
indigenous microbial community and local environmental conditions play a major
role in the biodegradation rate, which determines the biogeochemical events (Sarkar
et al. 2016). Microorganisms play a major role in mediating elemental biogeochemical cycles by mineralizing the organic material into inorganic through their
1 Microbial Degradation of Plastics and Its Biotechnological Advancement