Inference& Newer Developments

Traditional plastics even with various ingredients during compounding have yielded lesser than expected results on bio-degradability. Newer micro Organisms are being studied eg. Ideonellasakaiensis.

Ideonellasakaiensis is Gram-negative, aerobic, and rod-shaped bacteria. The discovery of Ideonellasakaiensis has potential importance for the degradation of PET plastics. Ideonellasakaiensis cells adhere to the PET surface and use a secreted PET hydrolase, or PETase, to degrade the PET into mono(2-hydroxyethyl)terephthalic acid (MHET), a heterodimer composed of terephthalic acid (TPA) and ethylene glycol. The I. sakaiensis PETase is the first PETase ever discovered and functions by hydrolyzing the ester bonds present in PET with high specificity. The resulting MHET is then degraded into its two monomeric constituents by a lipid-anchored MHET hydrolase enzyme, or MHETase, on the cell’s outer membrane.

Pestalotiopsismicrospora is a species of endophytic fungus capable of breaking down and digesting polyurethane. Its polyurethane degradation activity was discovered in two distinct P. microspora strains isolated from plant stems in the Yasuni National Forest within the Ecuadorian Amazon rainforest. It’s the first fungus species found to be able to subsist on polyurethane in anaerobic conditions. This makes the fungus a potential candidate for bioremediation projects involving large quantities of plastic.

Aspergillustubingensisa fungi has been studied in 2018for their ability to decompose plastic such as polyurethane in weeks rather than decades.

The caterpillar of G. mellonella has attracted interest for its ability to eat and digest polyethylene plastic. In laboratory experiments with G. mellonella caterpillars, about 100 caterpillars consumed 92 milligrams of a polyethylene-plastic shopping bag over the course of 12 hours. While it is clear that the caterpillars are consuming the plastic, more research needs to be done to determine if this chemistry is the result of G. mellonella or its gut flora. The moth’s larvae break down polyethylene to ethylene glycol and a mass loss of 13% polyethylene over 14 hours has been documented in polyethylene films. Two further strains of bacteria – Enterobacter asburiae and Bacillus species which have been demonstrated as capable of growing on and decomposing polyethylene plastic in a laboratory setting.