T w o actinomycete strains, DF-28 and DF-32T, were isolated from soil samples collected in a deciduous dipterocarp forest in Thailand. They produced longitudinally paired spores on the tips of short sporophores alternately branched from aerial hyphae, and the chemotaxonomic properties of the isolates were the same as those of members of the family Streptosporangiaceae. These phenotypic properties, together with the results of a phylogenetic analysis based on 16s rRNA gene sequences, indicated that these isolates should be assigned to the genus Microbispora. The two isolates showed more than 93% DNA relatedness to each other, but their relatedness to any previously described species of the genus Microbispora was only 4 5 % or less. They were distinguishable from previously described Microbispora spp. b y a combination of physiological and biochemical properties. Therefore, a new species is proposed for these strains, under the name Microbispora corallina sp. nov. The type strain is strain DF-32T ( = JCM 10267T).

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Medium optimization for production of raw starch degrading enzyme (RSDE) from a newly isolated thermophilic filamentous bacterium, Laceyella sacchari LP175, is described. Yeast extract and raw cassava starch were found to be the best nitrogen and carbon sources, respectively, for enzyme production. Response surface methodology with Plackett–Burman design and central composite design showed that an optimized concentration of 4.93 g/L raw cassava starch and 2.8 g/L yeast extract in basal medium yielded 181.1 U/mL RSDE activity in a shaking flask at 50°C and pH 7.0 after 48 h. Maximum RDSE activity in crude enzyme was achieved at pH 6.5 and 50°C. The major end product of raw cassava starch hydrolysis was maltose (88%). The Km and Ki values of raw cassava starch and maltose, respectively, were found to be 2.85 mg/mL and 1.04 mg/mL. Raw cassava starch at 100 g/L was hydrolyzed with 200 U/mL RSDE for 12 h, yielding 36.8% hydrolysis. The addition of commercial glucoamylase (1.6 U/mL) synergistically enhanced the hydrolysis reaction, yielding 70% hydrolysis (equivalent to 78.0 g/L glucose). The high efficiency of RSDE produced from L. sacchari LP175 could be useful for replacing conventional enzymes currently used in various raw starch processing industries.

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on an emulsified PLLA agar plate at 50 C. Among the isolates, strain LP175 showed the highest PLLAdegrading ability. It was closely related to Laceyella sacchari, with 99.9% similarity based on the 16S rRNA gene sequence. The PLLA-degrading enzyme produced by the strain was purified to homogeneity by 48.1% yield and specific activity of 328 U·mg-protein-1 with a 15.3-fold purity increase. The purified enzyme was strongly active against specific substrates such as casein and gelatin and weakly active against Suc-(Ala) 3 -pNA. Optimum enzyme activity was exhibited at a temperature of 60 C with thermal stability up to 50 C and a pH of 9.0 with pH stability in a range of 8.5 10.5. Molecular weight of the enzyme was approximately 28.0 kDa, as determined by gel filtration and SDS-PAGE. The inhibitors phenylmethylsulfonyl fluoride (PMSF), ethylenediaminetetraacetate (EDTA), and ethylene glycolbis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid (EGTA) strongly inhibited enzyme activity, but the activity was not inhibited by 1 mM 1,10-phenanthroline (1,10-phen). The N-terminal amino acid sequences had 100% homology with thermostable serine protease (thermitase) from Thermoactinomyces vulgaris. The results obtained suggest that the PLLA-degrading enzyme produced by L. sacchari strain LP175 is serine protease.Key words: Laceyella sacchari; PLLA-degrading enzyme; Thermoactinomycetaceae; thermophilic filamentous bacteria IntroductionPoly(L-lactide) (PLLA); (C 3 H 4 O 2 )n is one of the aliphatic biodegradable polyesters derived from renewable resources such as corn, cassava, sugar cane, rice and potato through lactic acid fermentation, and it is also fully degradable by both microbial and enzymatic processes (Tokiwa et al., 2009;Gupta et al., 2007;Jarerat et al., 2006;Tokiwa and Calabia, 2006;Tomita et al., 2004). PLLA, as an environmentally friendly (eco-friendly or green ) product, has been developed on a large scale and is currently used for a wide range of applications, including packaging materials (Bhalla et al., 2007;Nolan-Itu Pty Ltd., 2002), medical applications (Jalil, 1990), agricultural products (Gross and Kalra, 2002;Sakai et al., 2001) and textiles.Most PLLA-degrading microorganisms are found in the bacterial order Actinomycetales, e.g. the families Pseudonocardiaceae (Pranamuda and Tokiwa, 1999;Pranamuda et al., 1997), Thermomonosporaceae (Sangwan and Wu, 2008;Sukkhum et al., 2009b), and Streptosporangiaceae (Sukkhum et al., 2009b). Apart from that, thermophilic bacteria in the families Thermoactinomycetaceae (Sukkhum et al., 2009b) and Firmicutes (Oda et al., 2000;Sakai et al., 2001), filamentous fungi in the genera Tritirachium and Paecilomyces (Sangwan and Wu, 2008), and yeast in the genus Cryptococcus have also been reported to be PLLA-degrading microorganisms.Many different types of enzymes are found in PLLAdegrading microorganisms, such as: protease from Amycola- Full PaperCharacterization of poly(L-lactide)-degrading enzyme produced by thermophilic filamentous bacteria Laceyella sacchari LP175 (Received F...

^Äëíê~Åí= The fermentation process for a poly (L-lactide) (PLA)-degrading enzyme production by a newly isolate of thermophilic PLAdegrading ^Åíáåçã~Çìê~ sp. T16-1 was investigated. The strain produced 33.9 U/mL of enzyme activity after cultivation at 50°C under shaking of 150 rpm for 96 h in a medium consisting of (w/v) 0.05% PLA film, 0.2% gelatin, 0.4% (NH 4 ) 2 SO 4 , 0.4% K 2 HPO 4 , 0.2 % KH 2 PO 4 , and 0.02% MgSO 4 ⋅ 7H 2 O. The optimal concentration of PLA film and gelatin obtained by response surface methodology (RSM) for the highest production of PLA-degrading enzyme was 0.035% (w/v) and 0.238% (w/v), respectively. Under these conditions, the model predicted 40.4 U/mL of PLA-degrading activity and the verification of the optimization showed 44.6 U/mL of PLA-degrading enzymatic activity in the flasks experiment. The maximum PLAdegrading activity reached 150 U/mL within 72 h cultivation in the 3-L airlift fermenter. © KSBB hÉóïçêÇëW=Actinomadura=ëéKI=çéíáãáò~íáçåI=mi^JÇÉÖê~ÇáåÖ=ÉåòóãÉI=êÉëéçåëÉ=ëìêÑ~ÅÉ=ãÉíÜçÇçäçÖó

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