S.-A. Yoo

Characterization of an extracellular flocculating substance produced by a planktonic cyanobacterium, Anabaena sp.

Two planktonic cyanobacteria, Anabaena sp. N1444 and Anabaena sp. PC-1, and a green eukaryotic alga, Scene-desmus sp., produced extracellular flocculants. The flocculant of Anabaena PC-1, when purified, was found to be a macromolecular polysaccharide consisting of neutral sugars, uronic acids, and proteins, but not keto acids, hexosamines nor fatty acids. The flocculant bound a cationic dye, Alcian Blue, indicating it to be polyanionic. The flocculating activity was high under acidic conditions, slightly enhanced by the addition of salts and metals, and increased to about 40% upon heating at 100 °C for 7 min. The flocculant could flocculated various inorganic and organic compounds in solution.

Lysobacter daecheongensis sp. nov., isolated from sediment of stream near the Daechung dam in South Korea

A Gram-negative, aerobic, rod shaped, non-spore-forming bacterial strain, designated Dae08T, was isolated from sediment of the stream near Daechung dam in South Korea, and was characterized in order to determine its taxonomic position, using a polyphasic approach. Comparative 16S rRNA gene sequence analysis showed that strain Dae08T belongs to the family Xanthomonadaceae of the Gammaproteobacteria, and is related to Lysobacter brunescens ATCC 29482T (97.3%). The phylogenetic distances from any other species with validly published names within the genus Lysobacter were greater than 3.7%. The G+C contents of the genomic DNA of strain Dae08T was 69.3 mol%. The detection of a quinone system with Q-8 as the predominant compound and a fatty acid profile with iso-C15:0, iso-C17:1, ω9c, iso-C17:0, iso-C16:0, and iso-C11:0 3-OH as the major acids supported the affiliation of strain Dae08T to the genus Lysobacter. DNA-DNA relatedness between strain Dae08T and its phylogenetically closest neighbour was 28%. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain Dae08T (= KCTC 12600T) should be classified in the genus Lysobacter as the novel species, for which the name Lysobacter daecheongensis sp. nov. is proposed.

Lysobacter panaciterrae sp. nov., isolated from soil of a ginseng field

A Gram-negative, aerobic, rod-shaped, non-spore-forming bacterial strain, designated Gsoil 068(T), was isolated from soil of a ginseng field in Pocheon Province (South Korea), and was characterized to determine its taxonomic position by using a polyphasic approach. Comparative 16S rRNA gene sequence analysis showed that strain Gsoil 068(T) belonged to the family Xanthomonadaceae, class Gammaproteobacteria, and was related most closely to Lysobacter brunescens ATCC 29482(T) and Lysobacter gummosus ATCC 29489(T) (96.1 % sequence similarity). The G+C content of the genomic DNA of strain Gsoil 068(T) was 67.0 mol%. The detection of a quinone system with ubiquinone Q-8 as the predominant component and a fatty acid profile with iso-C(15 : 0), iso-C(17 : 1)omega9c, iso-C(17 : 0) and iso-C(11 : 0) 3-OH as the major components supported the affiliation of strain Gsoil 068(T) to the genus Lysobacter. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain Gsoil 068(T) is considered to represent a novel species of the genus Lysobacter, for which the name Lysobacter panaciterrae sp. nov. is proposed. The type strain is Gsoil 068(T) (=KCTC 12601(T) =DSM 17927(T)).

Dyadobacter soli sp. nov., a starch-degrading bacterium isolated from farm soil

A Gram-negative, non-motile, aerobic bacterial strain, designated MJ20(T), was isolated from farm soil near Daejeon (South Korea) and was characterized taxonomically by using a polyphasic approach. Comparative 16S rRNA gene sequence analysis showed that strain MJ20(T) belongs to the family Cytophagaceae, class Sphingobacteria, and was related most closely to Dyadobacter fermentans DSM 18053(T) (98.9 % sequence similarity), Dyadobacter beijingensis JCM 14200(T) (98.0 %) and Dyadobacter ginsengisoli KCTC 12589(T) (96.4 %). The G+C content of the genomic DNA of strain MJ20(T) was 48.5 mol%. The detection of MK-7 as the predominant menaquinone and a fatty acid profile with summed feature 4 (C(16 : 1)ω7c and/or iso-C(15 : 0) 2-OH), iso-C(15 : 0), C(16 : 0) and C(16 : 1)ω5c as major components supported the affiliation of strain MJ20(T) to the genus Dyadobacter. The new isolate exhibited relatively low levels of DNA-DNA relatedness with respect to D. fermentans DSM 18053(T) (mean±SD of three determinations, 47±7 %) and D. beijingensis JCM 14200(T) (38±8 %). On the basis of its phenotypic and genotypic properties together with phylogenetic distinctiveness, strain MJ20(T) (=KCTC 22481(T) =JCM 16232(T)) should be classified in the genus Dyadobacter as the type strain of a novel species, for which the name Dyadobacter soli sp. nov. is proposed.

Dokdonella ginsengisoli sp. nov., isolated from soil from a ginseng field, and emended description of the genus Dokdonella

A Gram-negative, aerobic, rod-shaped, non-motile, non-spore-forming bacterial strain, designated Gsoil 191T, was isolated from a soil sample from a ginseng field in Pocheon Province, South Korea, and was characterized taxonomically by using a polyphasic approach. Comparative 16S rRNA gene sequence analysis showed that strain Gsoil 191T belongs to the family Xanthomonadaceae and is related to Dokdonella fugitiva LMG 23001T (97.8% sequence similarity) and Dokdonella koreensis KCTC 12396T (96.9%). The G+C content of the genomic DNA was 68.7 mol%. The major respiratory quinone was Q-8 and the major fatty acids were iso-C17:1omega9c (30.6%), iso-C17:0 (21.6%) and iso-C15:0 (13.0%), supporting the affiliation of strain Gsoil 191T to the genus Dokdonella. DNA-DNA hybridization experiments showed that the DNA-DNA relatedness values between strain Gsoil 191T and its closest phylogenetic neighbours were below 40%. The results of physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain Gsoil 191T from recognized species of the genus Dokdonella. On the basis of its phenotypic properties and phylogenetic distinctiveness, strain Gsoil 191T represents a novel species of the genus Dokdonella, for which the name Dokdonella ginsengisoli sp. nov. is proposed. The type strain is Gsoil 191T (=KCTC 12564T=DSM 17954T=CCUG 52462T).

Carotinoid compositions of five microalga species

, astaxanthin [2, 3].The subjects of our study were five species of green alga (Division Chlorophyta) that were promising sources forproducing biodiesel fuel and polyunsaturated fatty acids. Herein we present data on the carotinoid compositions of thesemicroalgae grown under the conditions used by us earlier to obtain their oils.Green algae

Biotransformation of Ginsenoside Rb1 into Rd by the Bacterium Lysobacter panaciterrae

Triterpenoid saponins and ginsenosides, the majority of which contain the aglycons protopanaxadiol or protopanaxatriol, are important biologically active compounds of Panax ginseng C. A. Meyer. The principal ginsenoside, the content of which in ginseng root is >20% of the total saponins, is Rb1 (1), which includes -sophorose and -gentiobiose residues (6-O-Dglucopyranosyl-D-glucose) in the C-3 and C-20 positions, respectively, of 20(S)-protopanaxadiol. The minor ginsenoside Rd (2) is a close structural analog of Rb1 and has a glucose instead of -gentiobiose in the C-20 position [1]. Rd has a broader spectrum of biological activity than Rb1, for example, it increases the differentiation of nerve stem cells, protects neurons from neurotoxic substances, and inhibits proliferation of HepG2 liver cancer cells [2]. However, the content of Rd in ginseng root is 4–5 times less than that of Rb1. Therefore, biotransformation of ginsenoside Rb1 into Rd, in particular by using microorganisms, is of practical importance [3].

Castellaniella daejeonensis sp. nov., isolated from soil

A Gram-negative, non-spore-forming, motile, facultatively anaerobic bacterium, designated strain MJ06(T), was isolated from oil-contaminated soil and was characterized taxonomically by using a polyphasic approach. Strain MJ06(T) contained ubiquinone Q-8 as the major respiratory lipoquinone, putrescine as the predominant polyamine and phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylglycerol as major polar lipids. The G+C content of the genomic DNA of strain MJ06(T) was 66.2 mol%. The major fatty acids were summed feature 4 (C(16 : 1)ω 7c and/or iso-C(15 : 0) 2-OH; 32.5 %), C(16 : 0) (22.8 %) and summed feature 7 (one or more of C(18 : 1)ω 7c, C(18 : 1)ω 9t and C(18 : 1)ω 12t; 14.9 %). Comparative 16S rRNA gene sequence analysis showed that strain MJ06(T) belonged to the family Alcaligenaceae, class Betaproteobacteria, and joined the evolutionary radiation enclosed by the genus Castellaniella. Levels of 16S rRNA gene sequence similarity between strain MJ06(T) and its phylogenetically closest relatives, Castellaniella denitrificans NKNTAU(T), Castellaniella defragrans 54Pin(T), Castellaniella ginsengisoli DCY36(T) and Castellaniella caeni Ho-11(T), were 98.6, 98.3, 97.8 and 97.3 %, respectively. Levels of similarity between strain MJ06(T) and the type strains of all other recognized species in the family Alcaligenaceae were below 95.0 %. Strain MJ06(T) exhibited relatively low levels of DNA-DNA relatedness with respect to C. defragrans DSM 12141(T) (52 %), C. denitrificans DSM 11046(T) (31 %), C. ginsengisoli KCTC 22398(T) (18 %) and C. caeni KCTC 12197(T) (15 %). On the basis of its phenotypic and genotypic properties together with phylogenetic distinctiveness, strain MJ06(T) is considered to represent a novel species of the genus Castellaniella, for which the name Castellaniella daejeonensis sp. nov. is proposed. The type strain is MJ06(T) (=KCTC 22454(T) =JCM 16240(T)).

Biotransformation of ginsenoside Rb1 into F-2 and compound K by bacterium Sphingomonas sp. BG 25

Triterpenoid saponins and ginsenosides, the majority of which contain protopanaxadiol or protopanaxatriol as the aglycon, are important biologically active compounds of Panax ginseng C. A. Meyer. One of the principal ginsenosides, Rb1 (1), has -sophorose and -gentiobiose residues in the C-3 and C-20 positions, respectively, of 20(S)-protopanaxadiol. The minor ginsenoside F-2 (2) with glucose residues on C-3 and C-20 and compound K (3) with only one glucose on C-20 have structures close to that of Rb1 and are practically absent in ginseng roots [1]. Saponins 2 and 3 have broader spectra of biological activity than Rb1. For example, compound K inhibits growth of cultivated melanoma B16-B6, hepatocellular carcinoma Hep-G2, and lung carcinoma 95-D cells whereas F-2 induces apoptosis of breast cancer stem cells [1, 2].

Fatty-Acid Compositions of Three Strains of Blue-Green Algae Biomass, a Potential Feedstock for Producing Biodiesel Fuel

The most promising renewable feedstock for producing third-generation biofuel next to eukaryotic microalgae is prokaryotic blue-green algae, also known as cyanobacteria [1]. The compositions of their fatty acids (FA), which are converted to methyl or ethyl esters for use in the production of biodiesel fuel, are highly variable, like the algae themselves. The most important physicochemical properties of the fuel such as the cetane and iodine numbers and stability to oxidation and freezing are directly related to the fatty-acid composition of the starting biomass. The contents of several FA in biodiesel fuel are regulated by international standards such as EN 14214 [2]. Therefore, the search for cyanobacteria strains with FA compositions that satisfy existing standards is the most important research stage, to which much attention is paid [1]. Herein, we communicate information on the FA compositions of three cyanobacteria strains, the biomass of which is considered feedstock for producing biodiesel fuel. Blue-green alga Anabaena sp. BD47 was isolated from a natural aquifer near Daejeon (South Korea) and was identified taxonomically as strain BD47 based on morphological and physiological and biochemical characteristics. Cyanobacteria Anabaena sp. AG10059 and Synechococcus elongatus KMMCC-1063 were obtained from the Korean Collection for Type Cultures (KCTC) and the Korea Marine Microalgae Culture Center (KMMCC), respectively. All three cyanobacteria strains were cultivated in 18-cm cylindrical glass vessels containing modified BG-11 medium (8 L) for 7 d at 27–28°C with illumination by luminescent daylight lamps of intensity 140 E m–2 s–1 and continuous air bubbling. Microalgae cells were precipitated by centrifugation, rinsed with H2O, lyophilized, and extracted with CHCl3– MeOH (2:1 v/v). FA contents were analyzed by the published method [3]. Pigments were isolated and carotinoids were analyzed as before [4]. The total FA contents in Anabaena sp. BD47, Anabaena sp. AG10059, and S. elongatus KMMCC-1063 were 9.8, 11.7, and 14.6%, respectively, calculated for lyophilized biomass (LBM) of these microalgae. We found earlier that strain Anabaena sp. BD47 also produced poly(3-hydroxybutyrate) (PHB) (2.3%) [5]. We experimented simultaneously with the other two aforementioned strains but were unable to isolate PHB from them. This may be one reason for the lower FA content in Anabaena sp. BD47 because FA biosynthesis and PHB formation are competing metabolic pathways. However, PHB production is viewed as an undesirable process when selecting microalgae strains for producing biodiesel fuel from them [6]. Table 1 shows that the studied strains contained C12-C20 acids, the carbon chains of which satisfied the requirements for biodiesel fuel. The principal FA were 16:0 and 16:1(n-7), the main biodiesel components [2]. The qualitative characteristics of biodiesel fuel depend primarily on the ratio of saturated (SFA) to unsaturated (USFA) FA. The comparatively high SFA content observed in S. elongatus KMMCC-1063 had a positive effect on the cetane number and increased the stability of the fuel to oxidation but had a negative effect on its freezing stability [2]. Conversely, the relatively high USFA content observed in the Anabaena strains improved the last property but degraded the biodiesel fuel stability. The linolenic acid (18:3, n-3) contents in the three studied strains were within the upper limit of 12% imposed by European standard EN 14214 [2]. However, Anabaena sp. AG10059 and S. elongatus KMMCC-1063 were significantly more preferred according to this parameter than Anabaena sp. BD47. It is noteworthy that S. elongatus KMMCC-1063 lacked polyunsaturated FA that had a negative effect on the iodine number and had a high myristic acid (14:0) content that was rare for cyanobacteria and, together with lauric acid (12:0), was considered in some studies to be an ideal FA for producing biodiesel fuel [7].