The depolymerization reaction of poly(ethylene terephthalate) (PET) was analyzed on the basis of experimental and numerical data obtained from molecular orbital calculations. Various types of PETs polymerized by different methods and preheated by microwave irradiation were used to investigate the depolymerization mechanism. The activation energies obtained from the optimized structures of the ground state and the transition state were compared with the experimental data. On the basis of these comparisons, it was found that not only the crystallinity but also configuration changes caused by preheating were essential for realizing a high rate of transesterification reactions, such as depolymerization. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

The biodegradation of several dyes by starved intact cells and fresh intact cells of Pseudomonas pseudomallei 13NA has been studied. The degradation rate of the dyes by starved intact cells was faster than that of the dyes by fresh intact cells: starved cells degrade the dyes efficiently. It is considered that the degradation ability of the intact cells is dependent on nutritional circumstances and cell permeability of the dyes.