Degradation of a Terephthalate-containing Polyester by Thermophilic Actinomycetes and <Emphasis Type="Italic">Bacillus</Emphasis> Species Derived from Composts

We intended to find thermophilic degraders of terephthalate-containing Biomax^® films. Films in mesh bags were buried in composts (inside temperature: approximately 55–60 °C), resulting in the degradation of them in 2 weeks. Fluorescent microscopy of films recovered from composts showed that microorganisms gradually covered the surface of a film during composting. DGGE analysis of microorganisms on the composted film indicated the presence of Bacillus species as main species (approximately 80% of microbial flora) and actinomycetes (approximately 10–20%) as the second major flora. Isolation of Biomax^®-utilizing bacteria was focused on these two genera: two actinomycetes and one Bacillus species were isolated as pure best degraders from the composted polymer films, which were fragmented into small pieces. All the strains were thermophilic and identified, based on their 16S rDNA analyses. Degradation of polymer films was confirmed by (1) accelerated fragmentation of films in composts, compared with a control (no inoculum) and resultant decrease in molecular weights, (2) growth in a powdered Biomax^® medium, compared with a control without powdered Biomax^®, and (3) production of terephthalate in a powdered Biomax^® medium. In this way, we concluded that these bacteria were useful for degradation of thermostable Biomax^® products.     

火焰原子吸收分光光度法测定生活垃圾堆肥产品中铅

建立了硝酸-氢氟酸-高氯酸消解、火焰原子吸收分光光度法测定生活垃圾堆肥产品中铅的方法,试验了不同消解体系和共存离子对测定的影响.方法线性良好,检出限为20 mg/kg(按称取0.5 g试样消解定容至50 mL计算),对不同地域堆肥产品测定的RSD为2.6%～8.7%,加标回收率为89.0%～107%.