Biodegradability and Degrading Microbes of Low-Density Polyethylene

We have isolated and identified three types of low-density polyethylene (LDPE) degrading microbes, for the first time, from soil which was sampled from the field. It has been studied that thermooxidized or UV irradiation LDPE are degraded when incubated with mold (Volke-sepulveda et al., J Appl Polym Sci 2002, 83, 305; Yamada-Onodera et al., Polym Degrad Stab 2001, 72, 323); however, there was no article so far reporting the isolation of these particular microbes from the environment. Here, the mechanism of biodegradation of LDPE by the three microbes is described. We used LDPE film, which was buried in soil and biodegraded, and the surrounding soil, located at Nogi Town, Tochigi Prefecture, Japan as the sources of sample for this study. The sample was added to a liquid medium, together with powder of a photodegraded, antioxidant-free LDPE film, as the sole source of carbon. After enriched cultivation, three strains of microbes were separated from the medium. They were classified on the basis of LDPE degrading capabilities, confirmed by -OH generation and degradation traces. Using Bergey's Manual of Determinative Bacteriology, the genera of the microbes were identified as Bacillus circulans, Bacillus brevies, and Bacillus sphaericus, which belong among the Natto bacteria, common in soil. (C) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 111: 551-559, 2009