English Abstract

Biodegradability of Low Density Polyethylene (LDPE) and Discovery of LDPE-Degrading Microbes Tomoko WATANABE Chemicals Evaluation and Research Institute, Japan, Saitama, Japan Graduate School of Science and Technology, Nagasaki University, Nagasaki, Japan Yoshito OHTAKE Chemicals Evaluation and Research Institute, Japan, Saitama, Japan Hitoshi ASABE Hagihara Industries, Inc., Okayama, Japan Nobunao MURAKAMI Takenaka Co., Chiba, Japan Fumio KOYAMA ITOCHU Co., Minato-ku, Tokyo, Japan Hiroshi OHMURA Yakult Central Institute for Microbiological Research, Kunitachi, Tokyo, Japan Mutsuhisa FURUKAWA Graduate School of Science and Technology, Nagasaki University, Nagasaki, Japan Nippon Gomu Kyokaishi,(2007),80(11),409-415 Original Paper in Japanese Abstract Three types of low density polyethylene (LDPE)-degrading microbes were discovered, and unambiguous evidence for biodegradation of LDPE was presented. Pieces of LDPE film, buried and biodegraded, and their surrounding soil were used as the source of microbes. Powder of a photo-degraded and antioxidant-free LDPE film was added as the sole source of carbon in the liquid medium. From the medium that underwent enriched cultivation, three strains of microbes were separated. 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 genuses of the microbes were identified as Bacillus circulans, Bacillus brevies, Bacillus sphaericus, which belong among the natto bacteria, common in soil. Their degrading ability was confirmed on LDPE film previously photo-degraded by outdoor exposure for six weeks. After three months of cultivation, we identified the existence of body marks on the film surface, which are characteristic of microbial biodegradation. (Received on February 16, 2007) (Accepted on September 4, 2007) Keywords: LDPE (low density polyethylene), Biodegradation, Soil, Sole Source of Carbon, Microbes, Body Marks

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