18
biodegradation evaluation focused on CO 2 and CH 4 evolution, weight loss, and
molecular weight changes (Pathak and Navneet 2017). The biased experimental
designs can misinterpret biodegradation output, such as modified (starch or vegetable oil blending) or treated (thermal or UV pretreatment) plastic materials, studying
the same polymer from different sources with varying standard properties, using
different culture conditions and media, lack of overall understanding of biodegradation end products, limited information about enzymes involved in biodegradation
and genes encoding them, and lack of any definitive biodegradation mechanism and
implication of study in natural environments (Joutey et al. 2013). Also, regulation of
standard testing methods to account for the adverse effects of plastic leachate products in the food chain and mineralization processes in the ecosystem is needed
(Lithner et al. 2011; Pathak and Navneet 2017).
Few guidelines and regulations have been made for bioremediation research in a
defined way for its productive implications (Table 1.3). The world international
government forum engaged different countries in developing regulations in different aspects where, in year 1981, the Economic Co-operation and Development and
European Committee for Standardisation (1996) issued guidelines for standardized
biodegradation evaluation methods for plastic wastes, which include microbial respiration measurement for analytical determination of biodegradation and included
tests for characterizing the stability of plastic (Vroblesky 2001). They are likely to
be applied in countries where they were developed and a wide scope for the development of consistency in international standards (Table 1.3). The improvement in
experimental methodologies is essential to simplify the development of new biodegradability standards of plastics for simulating in natural environments to maintain
method and output consistency (Briassoulis and Dejean 2010).
Field practices can only provide the true measure and throughput for reliable
biodegradation research output. However, the results of exposure to the environment are likely to differ substantially from the laboratory scale study and to one
another’s environment. The degradation time scale may vary from month to year in
the environment than in laboratory experiments. However, there are challenges and
questions that have been addressed for new perspectives.
1.7 Biodegradable Polymers
Concerning with the non-degradability of petrochemical-based plastics, the development of biodegradable polymers has been emphasized as an alternative (Badia
et al. 2017). The increasing recalcitrant plastic pollutants and depleting the petroleum fraction; bio-based polymers have attracted attention and are considered as a
solution for environmental sustainability and conservation (Elsawy et al. 2017;
Panwar et al. 2011). Biodegradable polymers are considered bio-based or vice
versa, whereas biodegradable polymers decompose into CO 2 , H 2 O, and inorganic
compounds, and bio-based polymers are derived from biological sources that are
obviously biodegradable (i.e., polylactate, polybutyrate adipate terephthalate)
A. Kumari et al.
biodegradation evaluation focused on CO 2 and CH 4 evolution, weight loss, and
molecular weight changes (Pathak and Navneet 2017). The biased experimental
designs can misinterpret biodegradation output, such as modified (starch or vegetable oil blending) or treated (thermal or UV pretreatment) plastic materials, studying
the same polymer from different sources with varying standard properties, using
different culture conditions and media, lack of overall understanding of biodegradation end products, limited information about enzymes involved in biodegradation
and genes encoding them, and lack of any definitive biodegradation mechanism and
implication of study in natural environments (Joutey et al. 2013). Also, regulation of
standard testing methods to account for the adverse effects of plastic leachate products in the food chain and mineralization processes in the ecosystem is needed
(Lithner et al. 2011; Pathak and Navneet 2017).
Few guidelines and regulations have been made for bioremediation research in a
defined way for its productive implications (Table 1.3). The world international
government forum engaged different countries in developing regulations in different aspects where, in year 1981, the Economic Co-operation and Development and
European Committee for Standardisation (1996) issued guidelines for standardized
biodegradation evaluation methods for plastic wastes, which include microbial respiration measurement for analytical determination of biodegradation and included
tests for characterizing the stability of plastic (Vroblesky 2001). They are likely to
be applied in countries where they were developed and a wide scope for the development of consistency in international standards (Table 1.3). The improvement in
experimental methodologies is essential to simplify the development of new biodegradability standards of plastics for simulating in natural environments to maintain
method and output consistency (Briassoulis and Dejean 2010).
Field practices can only provide the true measure and throughput for reliable
biodegradation research output. However, the results of exposure to the environment are likely to differ substantially from the laboratory scale study and to one
another’s environment. The degradation time scale may vary from month to year in
the environment than in laboratory experiments. However, there are challenges and
questions that have been addressed for new perspectives.
1.7 Biodegradable Polymers
Concerning with the non-degradability of petrochemical-based plastics, the development of biodegradable polymers has been emphasized as an alternative (Badia
et al. 2017). The increasing recalcitrant plastic pollutants and depleting the petroleum fraction; bio-based polymers have attracted attention and are considered as a
solution for environmental sustainability and conservation (Elsawy et al. 2017;
Panwar et al. 2011). Biodegradable polymers are considered bio-based or vice
versa, whereas biodegradable polymers decompose into CO 2 , H 2 O, and inorganic
compounds, and bio-based polymers are derived from biological sources that are
obviously biodegradable (i.e., polylactate, polybutyrate adipate terephthalate)
A. Kumari et al.