Thermophilic actinomycetes strains were isolated from various environment in Taiwan and screened for degradation of poly(ethylene succinate) (PES), poly(epsilon-caprolactone) (PCL) and/or poly(beta-hydroxybutyrate) (PHB) by the clear-zone method. Out of 341 strains of thermophilic actinomycetes, 105 isolates were PHB-degraders (30.8%), 198 isolates were PCL-decomposers (58.1%), and 99 isolates could degrade PES (29.0%). Furthermore, 77 isolates could degrade both PHB and PCL (22.6%), 35 isolates could degrade both PHB and PES (10.3%), 81 isolates could degrade both PES and PCL (23.8%) and 31 isolates could degrade the three polyesters used in this study (9.1%). Base on the morphological and chemical characteristics, these 31 isolates belonging to Actinomadura (12.9%), Microbispora (25.8%), Streptomyces (48.4%), Thermoactinomyces (9.7%) and Saccharomonospora genus (3.22%).
Chitin is an abundant biopolymer composed of units of N-acetyl-D-glucosamine linked by β-1,4 glycosidic bonds. Chitin is the main component of the shells of mollusks, the cell wall of fungi and yeast and of the exoskeleton of crustaceans and insects. The degradation of chitin is catalyzed by chitinases that occur in a wide range of organisms. Among them, the chitinases from microorganisms are extremely important for the degradation and recycling of the carbon and nitrogen trapped in the large amount of insoluble chitin in nature. Streptomyces sp. TH-11 was isolated from the sediment of the Tou-Chien River, Taiwan. The chitinolytic enzyme activities were detected using a rapid in-gel detection method from the cell-free preparation of the culture medium of TH-11. The chitinolytic enzyme activity during prolonged liquid culturing was also analyzed by direct measurement of the chitin consumption. Decomposition of the exoskeleton of shrimps was demonstrated using electron microscopy and atomic force microscopy.
Thermophilic actinomycetes were isolated from sediment of the Chingshuei hot spring in north Taiwan, and the strain HS 45-1 was selected from colonies which formed distinct clear zones on agar plate with emulsified polyethylene succinate (PES). The film of PES disappeared within 6 days in liquid cultures at 50°C. The strain HS 45-1 was also able to degrade poly (-carpolactone) (PCL) and poly (3-hydroxybutyrate) (PHB) films completely within 6 days in liquid cultures. Basing on the results of phynotypic characteristics, phylogenetic studies and DNA-DNA hybridization, strain HS 45-1 should be assigned to Micorbispora rosea subsp. taiwanensis.
An actinomycete, strain BC 44T-5 T , with the ability to degrade poly(D-3-hydroxybutyrate) was isolated from a soil sample collected from Miaoli County, Taiwan. The isolate displayed substrate mycelia and short spore chains were borne on the aerial mycelia. Spores were non-motile, round, 1 mm in diameter and spiny. The aerial spore mass was blue. Strain BC 44T-5 T had meso-diaminopimelic acid as the diagnostic diamino acid of the cell-wall peptidoglycan. Whole-cell sugars of the novel strain were identified as glucose, galactose and madurose. Diphosphatidylglycerol and phosphatidylinositol were detected. The predominant menaquinones were MK-9(H 4 ) and MK-9(H 2 ). Mycolic acids were not detected. Major cellular fatty acids were iso-C 16 : 0 (14.82 %), C 16 : 0 (14.63 %), C 17 : 0 (13.79 %) and 10-methyl-C 17 : 0 (23.77 %.) The DNA G+C content of strain BC 44T-5 T was 70.6 mol%. On the basis of phenotypic and genotypic data, it is proposed that strain BC 44T-5 T (5FIRDI 002 T 5BCRC 16873 T 5LMG 24335 T ) should be classified as the type strain of a novel species of the genus Actinomadura, Actinomadura miaoliensis sp. nov.The genus Actinomadura was firstly described in 1970 (Lechevalier & Lechevalier, 1970) and currently comprises more than 30 species with validly published names (Lu et al., 2003;Cook et al., 2005;Lee & Jeong, 2006;Wang et al., 2007;le Roes & Meyers, 2007). Members of the genus are aerobic, Gram-positive, non-acid-alcohol-fast, non-motile organisms. Non-fragmentary substrate mycelia and aerial hyphae that differentiate into spore chains are present. The spore chains are of various lengths and can be straight, hooked or spiral on the tips of the aerial mycelium. Spores are oval or short-rod-like with smooth, spiny or warty surfaces and non-motile. Cells contain meso-diaminopimelic acid (A 2 pm) and the whole-cell sugars detected are madurose, glucose and galactose (type B; Lechevalier & Lechevalier, 1970). Major cellular fatty acids are iso-C 16 : 0 , C 16 : 0 , C 17 : 0 and 10-methyl-C 17 : 0 . Polar lipids belong to type I. The major menaquinones are MK-9(H 4 ) and MK-9(H 6 ). Mycolic acids are absent. Members of the genus have DNA G+C contents of 65-69 mol% (Meyer, 1989).During our screening of polyester-degrading thermophilic/ thermotolerant actinomycetes, some thermophilic/thermotolerant strains were isolated from soils in Taiwan (Tseng et al., 2007). In this study, an isolate belonging to the genus Actinomadura, strain BC 44T-5 T , is described. Poly(D-3-hydroxybutyrate) degradation data for strain BC 44T-5 T will be published at a later date. Based on characteristics determined by a polyphasic taxonomic study, i.e. phenotypic properties and phylogenetic and genetic data, it is proposed that the strain should be classified as a representative of a novel species of the genus Actinomadura.Strain BC 44T-5 T was isolated from a soil sample collected in Miaoli County, Taiwan, on HV agar (Hayakawa & Nonomura, 1987) incubated at 50 u C for 7 days. The strain was maintained on oatmeal agar and as a s...
Actinomycete strains were isolated from upstream and downstream regions of the Touchien River in Taiwan and screened for the ability to degrade poly(ethylene succinate) (PES), poly(-caprolactone) (PCL) and/or poly(b-hydroxybutyrate) (PHB) by the clear-zone method. Out of 305 isolates 135 isolates were PHB-degraders (44.2%), 83 isolates were PCLdecomposers (27.2%), and 64 isolates could degrade PES (21.0%). Furthermore, 46 isolates could degrade both PHB and PCL (15%), 39 isolates could degrade both PHB and PES (12.8%), and 12 isolates could degrade the three polyesters used in this study. Based on the appearance of isolates, the major isolates belong to the Streptomyces genus (91.9%) and Micromonospora genus (8.1%).
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