In the case that the depolymerizati

In the case that the depolymerization is conducted by chemical degradation or thermal degradation, both ends of a generated low molecular weight compound is irregular and such compound cannot be re-polymerized into a polymer. However, according to the depolymerization of the invention, a re-polymerizable oligomer mixture is generated. The oligomer mixture is easily re-polymerized into a polymer in the presence of a hydrolase or in a chemically synthetic manner. Furthermore, the hydrolase used to conduct the depolymerization or the polymerization can be collected and repeatedly used.