Submerged monoxenic culture medium development for Heterorhabditis bacteriophora and its symbiotic bacterium Photorhabdus luminescens: protein sources.

Most medium formulations for improving culture of entomopathogenic nematodes (EPN) based on protein sources have used enriched media like animal feed such as dried egg yolk, lactalbumin, and liver extract, among other ingredients. Most results, however, showed unstable yields and longer production time. Many of the results do not show the detailed parameters of fermentation. Soy flour, cotton seed flour, corn gluten meal, casein powder, soytone, peptone, casein hydrolysates, and lactalbumin hydrolysate as protein sources were tested to determine the source to support optimal symbiotic bacteria and nematode growth. The protein hydrolysates selected did not improve bacterial cell mass compared with the yeast extract control, but soy flour was the best, showing 75.1% recovery and producing more bacterial cell number (1.4×109/ml) than all other sources. The highest yield (1.85×105 IJs/ml), yield coefficient (1.67×106 IJs/g medium), and productivity (1.32×107 IJs/l/day) were also achieved at enriched medium with soybean protein.

Nocardioides panacisoli sp. nov., isolated from the soil of a ginseng field.

A Gram-positive, rod-shaped, non-spore-forming bacterium (Gsoil 346(T)) was isolated from the soil of a ginseng field in South Korea and was characterized in order to determine its taxonomic position. On the basis of 16S rRNA gene sequences, strain Gsoil 346(T) was shown to belong to the genus Nocardioides in the family Nocardioidaceae, with the most closely related species being Nocardioides aquiterrae GW-9(T) (96.6 % 16S rRNA gene sequence similarity); however, the strain clustered in a distinct branch of the phylogenetic tree with Nocardioides kongjuensis A2-4(T) (96.2 %), Nocardioides aromaticivorans H-1(T) (96.1 %), Nocardioides nitrophenolicus NSP41(T) (96.1 %) and Nocardioides simplex ATCC 15799(T) (95.9 %). Strain Gsoil 346(T) was characterized chemotaxonomically and found to have ll-2,6-diaminopimelic acid in the cell-wall peptidoglycan, phosphatidylinositol and phosphatidylglycerol as the major polar lipids, MK-8(H(4)) as the predominant menaquinone and iso-C(16 : 0), C(18 : 1)omega9c and C(17 : 1)omega8c as the major fatty acids. The G+C content of the genomic DNA of the novel strain was 73.0 mol%. These chemotaxonomic properties supported the placement of strain Gsoil 346(T) in the genus Nocardioides. The results of physiological and biochemical tests, along with the phylogenetic analysis, allowed strain Gsoil 346(T) to be differentiated genotypically and phenotypically from recognized species of the genus Nocardioides. Therefore, strain Gsoil 346(T) represents a novel species, for which the name Nocardioides panacisoli sp. nov. is proposed, with Gsoil 346(T) (=KCTC 19470(T)=DSM 21348(T)) as the type strain.

Mucilaginibacter daejeonensis sp. nov., isolated from dried rice straw.

A novel strain, designated Jip 10(T), isolated from dried rice straw, was characterized by a polyphasic approach to clarify its taxonomic position. The isolate was Gram-negative, facultatively aerobic, heterotrophic, non-motile, non-spore-forming and rod-shaped. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolate clustered with the genus Mucilaginibacter in the phylum Bacteroidetes. 16S rRNA gene sequence similarities between strain Jip 10(T) and the type strains of Mucilaginibacter gracilis and Mucilaginibacter paludis were 93.7 and 93.6 %, respectively. The G+C content of the genomic DNA was 48.1 mol%. Chemotaxonomic data [major menaquinone MK-7 and major fatty acids iso-C(15 : 0), iso-C(17 : 0) 3-OH and summed feature 3 (iso-C(15 : 0) 2-OH and/or C(16 : 1)omega7c)] supported the affiliation of strain Jip 10(T) to the genus Mucilaginibacter. However, the results of physiological and biochemical tests allowed phenotypic differentiation of strain Jip 10(T) from other Mucilaginibacter species with validly published names. Therefore, strain Jip 10(T) (=KCTC 12639(T) =LMG 23488(T)) was classified in the genus Mucilaginibacter as the type strain of a novel species, for which the name Mucilaginibacter daejeonensis sp. nov. is proposed.

Pedobacter daechungensis sp. nov., from freshwater lake sediment in South Korea.

A novel bacterial strain, designated Dae 13T, was isolated from sediment from a freshwater lake in Daejeon, South Korea, and was characterized taxonomically by using a polyphasic approach. The isolate was Gram-negative, aerobic, non-motile, non-spore-forming and rod-shaped. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolate belonged to the genus Pedobacter in the family Sphingobacteriaceae but was clearly separate from established species of this genus. The 16S rRNA gene sequence similarities between strain Dae 13(T) and type strains of Pedobacter species with validly published names ranged from 91.6 to 97.5 %. The G+C content of the genomic DNA was 33.8 mol%. Chemotaxonomic data, i.e. the presence of MK-7 as the major menaquinone and iso-C(15 : 0), C(16 : 0) and summed feature 3 (iso-C(15 : 0) 2-OH and/or C(16 : 1)omega7c) as the major fatty acids, supported the affiliation of strain Dae 13T to the genus Pedobacter. However, the results of physiological and biochemical tests allowed phenotypic differentiation of the isolate with respect to Pedobacter species with validly published names. Therefore, strain Dae 13T represents a novel species within the genus Pedobacter, for which the name Pedobacter daechungensis sp. nov. is proposed. The type strain is Dae 13T (=KCTC 12637T=LMG 23489T).