A novel Gram stain positive actinobacterium, designated RS-7-4(T), was isolated from a sea sediment sample collected in Indonesia, and its taxonomic position was investigated using a polyphasic approach. Strain RS-7-4(T) was observed to form vegetative hyphae in the early phase of growth, but the hyphae eventually fragmented into short rods to coccoid cells. Growth occurred at 15-37 °C, pH 6.0-11.0 and in the presence of 0-7 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequence comparisons revealed that strain RS-7-4(T) was closely related to the members of the genus Cellulosimicrobium, with a similarity range of 98.08-99.10 %. The peptidoglycan type of strain RS-7-4(T) was found to be A4α L-Lys-L-Thr-D-Asp. The predominant menaquinone was MK-9(H4), and the major fatty acids were anteiso-C15:0, iso-C15:0 and anteiso-C17:0. The DNA G+C content was 75.6 mol%. These chemotaxonomic features corresponded to those of the genus Cellulosimicrobium. Meanwhile, the results of DNA-DNA hybridization, and physiological and biochemical tests revealed that strain RS-7-4(T) was different from the recognized species of the genus Cellulosimicrobium. Therefore, strain RS-7-4(T) represents a novel species of the genus Cellulosimicrobium, for which the name Cellulosimicrobium marinum sp. nov. is proposed. The type strain is RS-7-4(T) (=NBRC 110994(T) =InaCC A726(T)).

Indonesia is one of the most biodiverse countries in the world and a promising resource for novel natural compound producers. Actinomycetes produce about two thirds of all clinically used antibiotics. Thus, exploiting Indonesia’s microbial diversity for actinomycetes may lead to the discovery of novel antibiotics. A total of 422 actinomycete strains were isolated from three different unique areas in Indonesia and tested for their antimicrobial activity. Nine potent bioactive strains were prioritized for further drug screening approaches. The nine strains were cultivated in different solid and liquid media, and a combination of genome mining analysis and mass spectrometry (MS)-based molecular networking was employed to identify potential novel compounds. By correlating secondary metabolite gene cluster data with MS-based molecular networking results, we identified several gene cluster-encoded biosynthetic products from the nine strains, including naphthyridinomycin, amicetin, echinomycin, tirandamycin, antimycin, and desferrioxamine B. Moreover, 16 putative ion clusters and numerous gene clusters were detected that could not be associated with any known compound, indicating that the strains can produce novel secondary metabolites. Our results demonstrate that sampling of actinomycetes from unique and biodiversity-rich habitats, such as Indonesia, along with a combination of gene cluster networking and molecular networking approaches, accelerates natural product identification.

An actinomycete strain, ID05-A0528T , was isolated using the SDS-yeast extract pre-treatment method from soil under mahogany (Swietenia mahogani) trees in West Timor, Indonesia, and was examined by using a polyphasic taxonomic approach. Chemotaxonomic and phylogenetic characterizations demonstrated that the novel strain belongs to the genus Dietzia. 16S rRNA gene sequencing studies showed that the strain was related to Dietzia cinnamea (97.2 %).Results of phenotypic and phylogenetic analyses determined that strain ID05-A0528 T is different from the known species of the genus Dietzia. It is proposed that the isolate should be classified as a representative of a novel species of the genus Dietzia, with the name Dietzia timorensis sp. nov. The type strain is ID05-A0528 T (5BTCC B-560 T 5NBRC 104184 T ).The genus Dietzia is a member of the suborder Corynebacterineae (Stackebrandt et al., 1997) and encompasses eight species at the time of writing, including Dietzia papillomatosis, Dietzia schimae and Dietzia cercidiphylli (Jones et al., 2008;Li et al., 2008). Known species of the genus Dietzia were originally isolated from several sources, including clinical materials, such as an alkaline soda lake, a perianal swab, a drain pool of a fish-egg processing plant, soil, the skin of an immunocompetent patient, and plant tissue (Duckworth et al., 1998;Yumoto et al., 2002;Yassin et al., 2006;Mayilraj et al., 2006;Jones et al., 2008;Li et al., 2008). Some strains identified as representing species of the genus Dietzia show degradation of hydrocarbons, including n-alkanes (Rainey et al., 1995;Chaillan et al., 2004;Yumoto et al., 2002). Additionally, Takeishi et al. (2006) reported xylanolytic strains of the genus Dietzia isolated from the hindgut and faeces of Trypoxylus dichotomus larvae. Hence, the discovery of additional species of this genus will help in understanding their ecological roles and provide bioresources for industrial applications, including bioremediation.Strain ID05-A0528 T was isolated from a soil sample collected under mahogany trees in West Timor. The SDS-yeast extract pre-treatment method (Hayakawa & Nonomura, 1989) and humic acid-vitamin agar (Hayakawa & Nonomura, 1987) containing nalidixic acid (20 mg l -1 ) were used in the isolation. The pre-treatment method was used to enhance the spore germination of actinomycetes and to decrease the number of nonfilamentous bacteria on the isolation plates. The aim of the present study was to determine the taxonomic position of isolate ID05-A0528 T using a polyphasic approach.The colonial properties of strain ID05-A0528 T were recorded from a modified Bennett's agar plate (Jones, 1949) that had been incubated for 14 days at 28 u C. Gramstaining was examined by using Hucker's method (Gerhardt, 1981). Motility was examined in hanging drops by light microscopy using culture grown on Bennett's agar plates. Morphology of the cells was observed using light microscopy. Tests for aesculin and arbutin hydrolysis (Williams et al., 1983), nitrate reduction (Gordon & Mihm,The...

Six actinomycete strains isolated from soil and plant-litter samples in Indonesia were studied for their taxonomic position by using a polyphasic approach. Phylogenetically, all the strains were located in the broad cluster of the genus Actinokineospora. Chemotaxonomic data [cell-wall diamino acid, meso-diaminopimelic acid; cell-wall peptidoglycan, type III (A1γ); major sugars, galactose and arabinose; major menaquinone, MK-9(H4); major fatty acid, iso-C16 : 0; major phospholipid, phosphatidylethanolamine] supported the affiliation of all six strains to the genus Actinokineospora. The results of DNA–DNA hybridization with DNA from type strains of Actinokineospora species with validly published names revealed three DNA–DNA relatedness groups. Group I (ID03-0561T) showed low relatedness to the other strains studied. The three strains in group II (ID03-0784T, ID03-0808 and ID03-0809) formed a group with high relatedness (98–100 %) and showed low relatedness to the other strains studied. The two strains in group III (ID03-0810T and ID03-0813) showed 58–68 % relatedness to Actinokineospora terrae NBRC 15668T and showed low relatedness (2–24 %) to the other strains studied. The description of three novel species is proposed: Actinokineospora baliensis sp. nov., for the single strain in group I (type strain ID03-0561T =BTCC B-554T =NBRC 104211T), Actinokineospora cibodasensis sp. nov., for the strains in group II (type strain ID03-0784T =BTCC B-555T =NBRC 104212T), and Actinokineospora cianjurensis sp. nov., for the strains in group III (type strain ID03-0810T =BTCC B-558T =NBRC 105526T).

The most biological multiplicity on this planet is almost certainly concealed in soils. Many valuable bacteria had been extensively dispersed in soils worldwide, with soils from terrestrial, desserts and Antarctic. Hence, soils become an intensively utilized ecological niche for the inhabitants to generate various useful biologically active natural products such asantibiotics, antifungal, antiviral, antioxidant, neuroprotection, anticancer and other important compounds. Bacteria including Actinobacteria have been exceptionally valuable for the pharmaceutical industry due to their limitless capability to generate secondary metabolites with various biological activities and chemical structure. Therefore, this article aims to provide critical insight of bioprospecting of microbes for valuable compounds to mankind.

Two actinomycete strains, ID05-A0653T and ID06-A0464T, were isolated from soils of West Timor and Lombok island, respectively, in Indonesia. 16S rRNA gene sequence analysis clearly demonstrated that the isolates belonged to the family Pseudonocardiaceae and were closely related to the genus Actinophytocola. Strains ID05-A0653T and ID06-A0464T exhibited 98.1 and 98.2 % 16S rRNA gene sequence similarity, respectively, with Actinophytocola oryzae GMKU 367T. The isolates grew well on ISP media and produced white aerial mycelium. Short spore chains were formed directly on the substrate mycelium. The isolates contained meso-diaminopimelic acid, arabinose and galactose as cell-wall components, MK-9(H4) as the sole isoprenoid quinone, iso-C16 : 0 as the major cellular fatty acid and phosphatidylethanolamine as the diagnostic polar lipid. The DNA G+C contents of strains ID05-A0653T and ID06-A0464T were 69.7 and 71.2 mol%, respectively. On the basis of phenotypic characteristics, DNA–DNA relatedness and 16S rRNA gene sequence comparisons, strains ID05-A0653T and ID06-A0464T each represent a novel species of the genus Actinophytocola, for which the names Actinophytocola timorensis sp. nov. (type strain ID05-A0653T  = BTCC B-673T  = NBRC 105524T) and Actinophytocola corallina sp. nov. (type strain ID06-A0464T  = BTCC B-674T  = NBRC 105525T) are proposed.

The strain Streptomyces sp. BSE7F, a novel Streptomyces strain isolated from Indonesian mangrove sediment, displays antimicrobial activities against Gram-positive bacteria, Gram-negative bacteria, and yeast.

Streptomyces sp. SHP22-7 is a novel strain isolated from a mangrove sample on Enggano Island, Indonesia.