Screening and identification of a polyurethane-degrading bacterium G-11 and its plastic degradation characteristics / 生物工程学报

Polyurethane (PUR) plastics is widely used because of its unique physical and chemical properties. However, unreasonable disposal of the vast amount of used PUR plastics has caused serious environmental pollution. The efficient degradation and utilization of used PUR plastics by means of microorganisms has become one of the current research hotspots, and efficient PUR degrading microbes are the key to the biological treatment of PUR plastics. In this study, an Impranil DLN-degrading bacteria G-11 was isolated from used PUR plastic samples collected from landfill, and its PUR-degrading characteristics were studied. Strain G-11 was identified as Amycolatopsis sp. through 16S rRNA gene sequence alignment. PUR degradation experiment showed that the weight loss rate of the commercial PUR plastics upon treatment of strain G-11 was 4.67%. Scanning electron microscope (SEM) showed that the surface structure of G-11-treated PUR plastics was destroyed with an eroded morphology. Contact angle and thermogravimetry analysis (TGA) showed that the hydrophilicity of PUR plastics increased along with decreased thermal stability upon treatment by strain G-11, which were consistent with the weight loss and morphological observation. These results indicated that strain G-11 isolated from landfill has potential application in biodegradation of waste PUR plastics.

Siderochelins with anti-mycobacterial activity from Amycolatopsis sp. LZ149 / 中国天然药物

Three new compounds, namely siderochelins D (2), E (3), and F (4), together with one known siderochelin A (1), were isolated from Amycolatopsis sp. LZ149 and elucidated by spectroscopic analyses including1D- and 2D-NMR and X-ray single crystal diffraction. Compounds 1-3 showed antibacterial activity against Mycobacterium smegmatis.

Characterization and antimicrobial activity of Amycolatopsis strains isolated from Thai soils.

The isolation and screening of antimicrobial activity of 3 actinomycete strains isolated from soil samples collected in Chaiyaphum, Nan and Phatthalung provinces, Thailand were carried out. Strains S39-7, KC19-1 and K57-1 were belonged to the genus Amycolatopsis based on their phenotypic and chemotaxonomic characteristics. On the basis of 16S rRNA gene sequence analysis, strain S39-7 was closely related to Amycolatopsis albidoflavus KCTC 9471T (99.2%). Strains KC19-1 and K57-1 were closely related to A. kentuckyensis NRRL B-24129T with 99.3 and 99.2% similarity, respectively. All of them contained meso-diaminopimelic acid (DAP) in cell wall peptidoglycan and had MK-9 (H4) as a major menaquinones. The DNA G+C contents of the strains ranged from 67.2 to 73.4 mol%. On secondary screening of antimicrobial activity, the ethyl acetate extract of the fermentation products of strain S39-7 was active against Staphylococcus aureus ATCC 6538, Bacillus subtilis ATCC 6633, Escherichia coli ATCC 25922, Kocuria rhizophila ATCC 9341, and Pseudomonas aeruginosa ATCC 27853 while strain KC 19-1 was active against only S. aureus ATCC 6538. Strain K 57-1 was active against E. coli ATCC 25922 and K. rhizophila ATCC 9341. In addition strain S39-7 could inhibit against methicillin resistant (MRSA) S. aureus 266.