title: Synergy of two thermophiles enables decomposition of poly-epsilon-caprolactone under composting conditions.
abstract: The ultimate degradation (i.e. complete mineralization) of biodegradable polymers proceeds through hydrolysis to the production of degradation intermediates (primary degradation) that are then taken into the microbial cell and further degraded to CO2 and water. We first isolated thermophilic actinomycete (Streptomyces thermonitrificans PDS-1), which has the activity of ultimate degradability, from compost in which poly-epsilon-caprolactone (PCL) degraded vigorously. We next tried to investigate the detailed mechanisms of degradation of the PCL in compost by developing a new experimental method in which isolated microorganisms are used to inoculate sterilized compost raw materials containing PCL. It was confirmed that the ultimate degradation of PCL could not be achieved by the action of the strain PDS-1 alone, and that a supplementary microorganism (Bacillus licheniformis HA1) isolated from compost utilizes the degradation intermediates and also increases the activity of the other primary microorganism (PDS-1) by adjusting the pH. We could thus show experimental proof of synergy between two thermophiles in the ultimate degradation of a biodegradable polymer in compost.
authors.affiliation: Department of Materials Science and Chemical Engineering, Shizuoka University, Hamamatsu, Japan. tcknaka@ipc.shizuoka.ac.jp
authors.forename: Kiyohiko
authors.initials: K
authors.lastname: Nakasaki
authors.forename: Haruki
authors.initials: H
authors.lastname: Matsuura
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tanaka
authors.forename: Takayuki
authors.initials: T
authors.lastname: Sakai
mesh_terms: D001407:Bacillus / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism*; D001673:Biodegradation, Environmental; D011091:Polyesters / Q000737:chemistry / Q000378:metabolism*; D012987:Soil; D012988:Soil Microbiology; D013302:Streptomyces / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism*; D013997:Time Factors
chemical_list: D011091:Polyesters; D012987:Soil; C016240:polycaprolactone