The long chains of the polymer are broken down into small molecules by extracellular
enzymes that are absorbed for further metabolism inside
the cell. The biodegradation of polymers is usually started
by oxidation process. Oxidases and peroxidases oxidize
appropriate substrates to carbonyls, alcohols or aldehyde
groups. Peroxidases reduce dissolved oxygen to
peroxide. Laccases reduce oxygen to water and oxidize
phenolic and non-phenolic substrates with the formation of quinones or phenoxy radicals and cation radicals