Biodegradability of Scott-Gelead photodegradable polyethylene and polyethylene wax by microorganisms

This paper describes the biodegradability of photodegraded polyethylene (PE) and commercial PEwax and molecular size limits of PE for biodegradation. Photodegradation was accelerated by Scott-Gelead System. Photofragmented PE and commercial PEwax were used as a sole carbon and energy source for soil microorganisms, respectively. Biodegradation by microbial consortia was confirmed by the increase of viable cell numbers and GPC analysis of PE added. Significant weigh decrease of PE samples added was also observed. Both photofragmented PE and PEwax were suggested to be biodegradable up to <(Mw)over bar> 5,000 or more: <(Mw)over bar> lower than 500 was degraded by more than 40 %. <(Mw)over bar>500-2,000 was by more than 10 %. <(Mw)over bar> higher than 2,000 was only by a few %. Logarithms of biodegradation ratio (%) and <(Mw)over bar> were correlated to show linearity and to suggest the biodegradability limit close to <(Mw)over bar> 10,000.