Rhizobium pongamiaesp. nov. from Root Nodules ofPongamia pinnata

Pongamia pinnatahas an added advantage of N2-fixing ability and tolerance to stress conditions as compared with other biodiesel crops. It harbours “rhizobia” as an endophytic bacterial community on its root nodules. A gram-negative, nonmotile, fast-growing, rod-shaped, bacterial strain VKLR-01Twas isolated from root nodules ofPongamiathat grew optimal at 28°C, pH 7.0 in presence of 2% NaCl. Isolate VKLR-01 exhibits higher tolerance to the prevailing adverse conditions, for example, salt stress, elevated temperatures and alkalinity. Strain VKLR-01Thas the major cellular fatty acid as C18:1 ω7c (65.92%). Strain VKLR-01Twas found to be a nitrogen fixer using the acetylene reduction assay and PCR detection of anifH gene. On the basis of phenotypic, phylogenetic distinctiveness and molecular data (16S rRNA,recA, andatpD gene sequences, G + C content, DNA-DNA hybridization etc.), strain VKLR-01T= (MTCC 10513T= MSCL 1015T) is considered to represent a novel species of the genusRhizobiumfor which the nameRhizobium pongamiaesp. nov. is proposed.Rhizobium pongamiaemay possess specific traits that can be transferred to other rhizobia through biotechnological tools and can be directly used as inoculants for reclamation of wasteland; hence, they are very important from both economic and environmental prospects.

Actibacterium mucosum gen. nov., sp. nov., a marine alphaproteobacterium from Mediterranean seawater

Strain R46T, a marine alphaproteobacterium, was isolated from Mediterranean seawater at Malvarrosa beach, Valencia, Spain. It is an aerobic chemo-organotrophic, mesophilic and slightly halophilic organism, with complex ionic requirements. Phylogenetic analyses based on the 16S rRNA and gyrB gene sequences showed that strain R46T formed a separate branch within the family Rhodobacteraceae , bearing similarities below 94.7 and 80.3 %, respectively, to any other recognized species. It contained Q10 as the predominant isoprenoid quinone and C18 : 1ω7c/C18 : 1ω6c as the major cellular fatty acid. Phosphatidylglycerol was the only identified polar lipid, although other lipids were also detected. The DNA G+C content of the genomic DNA was 61.3 mol%. On the basis of extensive phenotypic and phylogenetic comparative analysis, it is concluded that the strain represents a novel genus and species, for which the name Actibacterium mucosum gen. nov., sp. nov. is proposed. The type strain of the type species is Actibacterium mucosum R46T ( = CECT 7668T = KCTC 23349T).

Nonomuraea bangladeshensis sp. nov. and Nonomuraea coxensis sp. nov.

Two novel bacterial strains were isolated from sandy soil from Cox's Bazar, Bangladesh. Strains 5-10-10T and 5-38-42T were Gram-positive, aerobic, non-motile actinomycetes that form branched substrate and aerial mycelium. On the basis of 16S rRNA gene sequence similarity studies, the novel strains were shown to belong to the genus Nonomuraea, being most closely related to Nonomuraea fastidiosa. Chemotaxonomic data supported the assignment of the novel strains as members of the genus Nonomuraea. Strain 5-10-10T contained MK-9(H4) and strain 5-38-42T contained MK-9(H6) and MK-9(H4) as the major menaquinones. Major polar lipids were phosphatidylethanolamine and hydroxyphosphatidylethanolamine. The major cellular fatty acid for strain 5-10-10T was iso-C16 : 0 (26.4 %); C16 : 0 (17.4 %) was the major cellular fatty acid for strain 5-38-42T. The results of DNA–DNA hybridization and physiological tests enabled strains 5-10-10T and 5-38-42T to be differentiated genotypically and phenotypically from each other and from the closely related species, N. fastidiosa. On the basis of these results, strains 5-10-10T and 5-38-42T represent two novel species of the genus Nonomuraea. Following an evaluation of morphological, physiological and chemotaxonomic characteristics, 16S rRNA gene sequence comparisons and DNA–DNA hybridization experiments, the new isolates are proposed as two novel species, Nonomuraea bangladeshensis sp. nov. [type strain, 5-10-10T (=MTCC 8089T=JCM 13930T)] and Nonomuraea coxensis sp. nov. [type strain, 5-38-42T (=MTCC 8090T=JCM 13931T)].

Paenibacillus hodogayensis sp. nov., capable of degrading the polysaccharide produced by Sphaerotilus natans

Sphaerotilus natans is a sheathed bacterium often found in activated sludge that has a bulking problem. A bacterial strain that is able to degrade the extracellular polysaccharide produced by S. natans was isolated. The isolate was a spore-forming, aerobic, rod-shaped bacterium. The Gram reaction was variable or negative. The optimum growth temperature was 30 °C and the optimum pH was 8. The G+C content of the DNA was 55 mol%. The major cellular fatty acid and respiratory quinone were anteiso-C15 : 0 and MK-7, respectively. Phylogenetic analysis based on the 16S rRNA gene indicated that the isolate was a member of the genus Paenibacillus. The nearest relative, with a similarity of 94·2 %, was Paenibacillus koleovorans, a bacterium capable of degrading the sheath of S. natans. The phenotypic characteristics of the isolate were apparently different from those of related species in the genus Paenibacillus. It is proposed that the isolate be designated Paenibacillus hodogayensis sp. nov. The type strain is SGT (=JCM 12520T=KCTC 3919T).

Paenibacillus antarcticus sp. nov., a novel psychrotolerant organism from the Antarctic environment

An endospore-forming strain, 20CMT, was isolated from Antarctic sediment and identified as a member of the genus Paenibacillus on the basis of phenotypic and phylogenetic analyses. The organism stained Gram-variable and was facultatively anaerobic. Strain 20CMT was psychrotolerant, growing optimally at 10–15 °C. Like other Paenibacillus species, it contained anteiso-C15 : 0 as the major cellular fatty acid. The DNA G+C content was 40·7 mol%. 16S rRNA gene sequence analysis placed strain 20CMT within the Paenibacillus cluster, with a similarity value of 99·5 % to Paenibacillus macquariensis DSM 2T. DNA–DNA hybridization experiments between the Antarctic isolate and P. macquariensis DSM 2T revealed a reassociation value of 47 %, indicating that strain 20CMT and P. macquariensis DSM 2T belong to different species. Based on evaluation of morphological, physiological, chemotaxonomic and phylogenetic analyses, a novel species, Paenibacillus antarcticus sp. nov., is proposed; the type strain is 20CMT (=LMG 22078T=CECT 5836T).

Effect of growth substrates on fatty acid composition of Corynebacterium cyclohexanicum

Fatty acids occurring in lipids of Corynebacterium cyclohexanicum are 12-mefhyltridecanoic, myristic, 13-methyltetradecanoic, 12-methyltetradecanoic, n-pentadecanoic, 14-methylpentadecanoic, palmitic, 15-methylhcxadecanoic, and 14-methylhexadecanoic (in order of increasing retention times) identified by gas–liquid chromatographic retention characteristics and mass spectrometry. In glucose-grown cells, 12-methyltetradecanoic (35%) and 14-methylpentadecanoic (35%) acids were major acid components, whereas in the cells grown on cyclohexanecarboxylic, m-hydroxybenzoic, butyric, and acetic acids, 12-methyltetradecanoic acid was always the major cellular fatty acid, constituting 65–81% of the total fatty acids. The phase transition temperature of phospholipid sample from cells grown on glucose (22 °C) was higher than the corresponding values with butyrate (10 °C) and acetate (13 °C). The upper limit of growth temperature, however, was no different between cells grown on butyrate or glucose.