The DNA Base Composition of the Type Strains of the Genus Bacillus

Bacillus thermophilum sp. nov., isolated from a microbial fuel cell

A novel thermophilic, Gram-staining positive bacterium, designated DX-2(T), was isolated from the anode biofilm of a microbial fuel cell. Cells of the strain were oxidase positive, catalase positive, facultative anaerobic, motile rods. The isolate grew at 30-60 °C (optimum 50 °C) and pH 5-9 (optimum pH 8-8.5). The pairwise 16S rRNA gene sequence similarities showed that strain DX-2(T) was most closely related to Bacillus fumarioli LMG 17489(T) (96.2 %), B. firmus JCM 2512(T) (96.0 %) and B. foraminis DSM 19613(T) (95.7 %). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain DX-2(T) formed a cluster with B. smithii (95.5 %) and B. infernus (94.9 %). The genomic G+C content of DX-2(T) was 43.7 mol%. The predominant respiratory quinone was MK-7. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and unknown phospholipids. The major cellular fatty acid was iso-C16:0. Based on its phenotypic characteristics, chemotaxonomic features, and results of phylogenetic analysis, the strain was identified to represent a distinct novel species in the genus Bacillus, and the name proposed is B. thermophilum sp. nov. The type strain is DX-2(T) (=CCTCC AB2012194(T) = KCTC 33128(T)).

Selection of starter cultures for the production of kinema, a fermented soybean food of the Himalaya

Kinema, a traditional fermented soybean food, serves as a low-cost source of protein in the diet of the people of the Himalaya. The traditional method of kinema preparation results in a product with inconsistent quality. Forty five strains of spore-forming bacteria were isolated from nine samples of kinema collected from markets in the Darjeeling hills and Sikkim in India. Of these, 10 strains, identified as Bacillus subtilis (Ehrenberg) Cohn, were selected as possible starter cultures on the basis of enzyme activities and the production of slimy material. Protease activity (U/ml), α-amylase activity (U/ml) and relative viscosity of the selected strains were 6.5 to 81.5, 0.1 to 9.3, and 1.1 to 20.1, respectively. Kinema produced by these strains showed nitrogen contents (expressed as a percentage of the total nitrogen content) of: water-soluble N, 48.4 to 76.5; TCA-soluble N, 16.0 to 27.6; formal N, 5.0 to 12.5; ammonia-N, 4.4 to 7.8%. Reducing sugar was 1.1 to 2.0% of the wet weight and relative viscosity was from 2.0 to 35.2. Correlation matrices of the biochemical parameters and sensory attributes of the kinema produced by these B. subtilis strains were statistically analysed. Strains KK-2:B10 and GK-2:B10 of B. subtilis were the best starter cultures for improved kinema production.

Bacillus sediminis sp. nov., isolated from an electroactive biofilm

A Gram-stain positive, facultative anaerobic, motile, spore-forming rod-shaped bacterium with peritrichous flagella, designated DX-5(T), was isolated from an electroactive biofilm. Growth was observed to occur at 35-60 °C, at pH 7.0-10.0 and with 0.5-10 % (w/v) NaCl (optimum growth: 50 °C, pH 8.0 and 0.5-3 % NaCl). Cells were determined to be catalase- and oxidase-positive. The predominant respiratory quinone was identified as MK-7; the major polar lipids were determined to be diphosphatidylglycerol, phosphatidylglycerol, glycolipid, aminoglycolipid and an unidentified phospholipid; the DNA G+C content was determined to be 46.6 mol%; and the major fatty acids (>5 %) were identified as anteiso-C15:0 (33.6 %), iso-C15:0 (24.1 %) and anteiso-C17:0 (13.4 %). The phylogenetic analysis based on 16S rRNA gene sequence comparisons indicated that strain DX-5(T) should be assigned to the genus Bacillus, and was related most closely to the type strains of B. fortis DSM 16012(T) (96.3 %), B. composti KACC 16872(T) (96.3 %) and B. fordii DSM 16014(T) (95.8 %). Results of phenotypic, chemotaxonomic and genotypic analysis indicated that strain DX-5(T) represents a novel species, for which the name B. sediminis sp. nov. is proposed. The type strain is DX-5(T) (=CGMCC 1.12412(T) = KCTC 33102(T)).

Bacillus thermotolerans sp. nov., a thermophilic bacterium capable of reducing humus

A novel thermotolerant bacterium, designated SgZ-8(T), was isolated from a compost sample. Cells were non-motile, endospore-forming, Gram-staining positive, oxidase-negative and catalase-positive. The isolate was able to grow at 20-65 °C (optimum 50 °C) and pH 6.0-9.0 (optimum 6.5-7.0), and tolerate up to 9.0 % NaCl (w/v) under aerobic conditions. Anaerobic growth occurred with anthraquinone-2,6-disulphonate (AQDS), fumarate and NO3(-) as electron acceptors. Phylogenetic analysis based on the16S rRNA and gyrB genes grouped strain SgZ-8(T) into the genus Bacillus, with the highest similarity to Bacillus badius JCM 12228(T) (96.2 % for 16S rRNA gene sequence and 83.5 % for gyrB gene sequence) among all recognized species in the genus Bacillus. The G+C content of the genomic DNA was 49.3 mol%. The major isoprenoid quinone was menaquinone 7 (MK-7) and the polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and an unidentified phospholipid. The major cellular fatty acid was iso-C16 : 0. On the basis of its phenotypic and phylogenetic properties, chemotaxonomic analysis and the results of physiological and biochemical tests, strain SgZ-8(T) ( = CCTCC AB 2012108(T) = KACC 16706(T)) was designated the type strain of a novel species of the genus Bacillus, for which the name Bacillus thermotolerans sp. nov. is proposed.

Diversity and phylogeny of culturable spore-forming Bacilli isolated from marine sediments

Members of the genus Bacillus and related genera are ubiquitous in nature. However, Bacillus species isolated from marine sediments have attracted less interest respect to their terrestrial relatives. Here, we report the phylogenetic diversity of a collection of 96 Bacilli, isolated from 17 distinct stations of 5 oceanographic campaigns. The diversity was analysed by phenotypic and molecular approaches based on the amplified rDNA restriction analysis (ARDRA), amplification of the internal transcribed spacers (ITS-PCR) and on 16S rRNA sequencing. Intra-specific polymorphism was efficiently detected by biochemical analysis and ARDRA while results of ITS-PCR were in agreement with 16S rRNA sequencing. The identification results assigned 68% of the isolates to the species B. subtilis, B. licheniformis, B. pumilus and B. cereus. Phylogenetic analysis allowed the separation of 9 isolates in a clade that may represent a group of obligate marine Bacillus since they clustered with B. firmus, B. foraminis and marine isolates with metal oxidation and bioaccumulation capabilities. The remaining isolates showed a close affiliation to the genera Virgibacillus, Gracilibacillus and Paenibacillus. The widespread of Bacilli and their high diversity level observed in this work point out the need of more extensive studies to understand their distribution and ecology in deep-sea environments.

Proposal of Viridibacillus gen. nov. and reclassification of Bacillus arvi, Bacillus arenosi and Bacillus neidei as Viridibacillus arvi gen. nov., comb. nov., Viridibacillus arenosi comb. nov. and Viridibacillus neidei comb. nov

A polyphasic study was undertaken to clarify the taxonomic position of endospore-forming strains 433-D9, 433-E17 and 121-X1. BOX-PCR-generated fingerprints indicated that they may be members of a single species. 16S rRNA gene sequence similarity demonstrated that a representative of this group, 433-D9, is affiliated closely with Bacillus arvi DSM 16317(T) (100 %), Bacillus arenosi DSM 16319(T) (99.8 %) and Bacillus neidei NRRL BD-87(T) (97.1 %). Sequence similarities revealed Bacillus pycnus NRRL NRS-1691(T) and several Kurthia species as the next nearest relatives. DNA-DNA hybridization results showed that strain 433-D9 is a member of B. arvi. Detection of l-Lys-d-Asp-based peptidoglycan in strain 433-D9, B. arvi DSM 16317(T) and B. arenosi DSM 16319(T) was in agreement with their close relationship, but differentiated these strains from B. neidei NRRL BD-87(T) and B. pycnus NRRL NRS-1691(T), for which l-Lys-d-Glu was reported. A similar quinone system was detected in strains 433-D9, 433-E17, 121-X1, B. arvi DSM 16317(T), B. arenosi DSM 16319(T) and B. neidei NRRL BD-87(T). This system, unusual for bacilli, consisted of the major compound menaquinone MK-8 (69-80 %) and moderate amounts of MK-7 (19-30 %). This observation was in contrast to the predominance of MK-7 of the closest relative B. pycnus NRRL NRS-1691(T), as also reported for representatives of the closely related non-endospore-forming genus Kurthia. Strains 433-D9, B. arvi DSM 16317(T) and B. arenosi DSM 16319(T) exhibited homogeneous and discriminative polar lipid profiles and fatty acid profiles consisting of major acids i-C(15 : 0) and ai-C(15 : 0) and moderate amounts of i-C(17 : 1)omega10c and i-C(17 : 1) I/ai-C(17 : 1) B that discriminated them from closely related strains such as B. neidei NRRL BD-87(T). On the basis of clear-cut discriminative chemotaxonomic markers, we propose strains 433-D9, 433-E17 and 121-X1, B. arvi DSM 16317(T), B. arenosi DSM 16319(T) and B. neidei NRRL BD-87(T) to be reclassified within a separate genus. For this new taxon, we propose the name Viridibacillus gen. nov., and we propose the reclassification of Bacillus arvi, Bacillus arenosi and Bacillus neidei as Viridibacillus arvi gen. nov., comb. nov. (the type species of Viridibacillus, with the type strain DSM 16317(T) =LMG 22165(T)), Viridibacillus arenosi comb. nov. (type strain DSM 16319(T) =LMG 22166(T)) and Viridibacillus neidei comb. nov. (type strain NRRL BD-87(T) =DSM 15031(T) =JCM 11077(T)).

Proposal of Lysinibacillus boronitolerans gen. nov. sp. nov., and transfer of Bacillus fusiformis to Lysinibacillus fusiformis comb. nov. and Bacillus sphaericus to Lysinibacillus sphaericus comb. nov

Three strains of a spore-forming, Gram-positive, motile, rod-shaped and boron-tolerant bacterium were isolated from soil. The strains, designated 10aT, 11c and 12B, can tolerate 5 % (w/v) NaCl and up to 150 mM boron, but optimal growth was observed without addition of boron or NaCl in Luria–Bertani agar medium. The optimum temperature for growth was 37 °C (range 16–45 °C) and the optimum pH was 7.0–8.0 (range pH 5.5–9.5). A comparative analysis of the 16S rRNA gene sequence demonstrated that the isolated strains were closely related toBacillus fusiformisDSM 2898T(97.2 % similarity) andBacillus sphaericusDSM 28T(96.9 %). DNA–DNA relatedness was greater than 97 % among the isolated strains and 61.1 % withB. fusiformisDSM 2898Tand 43.2 % withB. sphaericusIAM 13420T. The phylogenetic and phenotypic analyses and DNA–DNA relatedness indicated that the three strains belong to the same species, that was characterized by a DNA G+C content of 36.5–37.9 mol%, MK-7 as the predominant menaquinone system and iso-C15 : 0(32 % of the total) as a major cellular fatty acid. In contrast to the type species of the genusBacillus, the strains contained peptidoglycan with lysine, aspartic acid, alanine and glutamic acid. Based on the distinctive peptidoglycan composition, phylogenetic analyses and physiology, the strains are assigned to a novel species within a new genus, for which the nameLysinibacillus boronitoleransgen. nov., sp. nov. is proposed. The type strain ofLysinibacillus boronitoleransis strain 10aT(=DSM 17140T=IAM 15262T=ATCC BAA-1146T). It is also proposed thatBacillus fusiformisandBacillus sphaericusbe transferred to this genus asLysinibacillus fusiformiscomb. nov. andLysinibacillus sphaericuscomb. nov., respectively.

A novel highly boron tolerant bacterium, Bacillus boroniphilus sp. nov., isolated from soil, that requires boron for its growth

Three strains of gram-positive, motile, rod-shaped and boron (B)-tolerant bacterium were isolated from naturally B containing soil of Hisarcik area in the Kutahya Province, Turkey. The strains, designated as T-14A, T-15Z(T) and T-17s, produced spherical or ellipsoidal endospores in a terminal bulging sporangium. The strains required B for the growth and can tolerate more than 450 mM B. These also tolerated up to 7.0% (w/v) NaCl in the presence of 50 mM B in agar medium but grew optimally without NaCl. The temperature range for growth was 16-37 degrees C (optimal of 30 degrees C), whereas the pH range was 6.5-9.0 (optimal of 7.5-8.5). The DNA G + C content was 41.1-42.2 mol% and the predominant cellular fatty acid was iso-C(15:0). The major respiratory quinone system was detected as MK-7 and the diamino acid of the peptidoglycan was meso-diaminopimelic acid. Based on phenotypic and chemotaxonomic characteristics, phylogenetic analysis of 16S rRNA gene sequences data and DNA-DNA re-association values, we concluded that the three strains belong to a novel species of the genus Bacillus, the type strain of which is T-15Z(T) and for which we proposed the name, B. boroniphilus sp. nov. (DSM 17376(T) = IAM 15287(T) = ATCC BAA-1204(T)).

Thermotolerant Bacillus licheniformis TY7 produces optically active l-lactic acid from kitchen refuse under open condition

A thermotolerant l-lactic-acid-producing bacterium was isolated and identified as Bacillus licheniformis TY7. TY7 shows optimum growth at pH 6.5 at 30 degrees C and normal growth up to 65 degrees C. Using nonsterile kitchen refuse at 50 degrees C, the strain produced 40 g/ll-lactic acid with 97% optical activity and 2.5 g/lxh productivity.

Bacillus galactosidilyticus sp. nov., an alkali-tolerant β-galactosidase producer

A novel Bacillus isolate from raw milk and four strains from diverse origins that were identified previously as Bacillus lentus, Bacillus firmus and Bacillus circulans showed a high degree of similarity in amplified rDNA restriction analysis, SDS-PAGE and routine phenotypic tests, whilst 16S rDNA sequence comparisons and DNA relatedness data showed that this taxon was different from related Bacillus species. On the basis of these data, Bacillus galactosidilyticus sp. nov. is proposed, with the type strain LMG 17892T (=DSM 15595T=Logan B2188T=MB 800T).

Virgibacillus carmonensis sp. nov., Virgibacillus necropolis sp. nov. and Virgibacillus picturae sp. nov., three novel species isolated from deteriorated mural paintings, transfer of the species of the genus salibacillus to Virgibacillus, as Virgibacillus marismortui comb. nov. and Virgibacillus salexigens comb. nov., and emended description of the genus Virgibacillus

A group of 13 strains was isolated from samples of biofilm formation on the mural paintings of the Servilia tomb (necropolis of Carmona, Spain) and the Saint-Catherine chapel (castle at Herberstein, Austria). The strains were subjected to a polyphasic taxonomic study, including (GTG)5-PCR, 16S rDNA sequence analysis, DNA-DNA hybridizations, DNA base ratio determination, analysis of fatty acids, polar lipids and menaquinones and morphological and biochemical characterization. In a phylogenetic tree based on neighbour-joining of 16S rDNA sequences, the strains are divided in two major groups, representing three novel species according to DNA-DNA relatedness, that are positioned at approximately equal distances from Virgibacillus and Salibacillus. After comparison of the novel results with existing data, the transfer of the species of Salibacillus to Virgibacillus is proposed, with the resulting new combinations Virgibacillus marismortui comb. nov. and Virgibacillus salexigens comb. nov. Additionally, three novel species are described, for which the names Virgibacillus carmonensis sp. nov., Virgibacillus necropolis sp. nov. and Virgibacillus picturae sp. nov. are proposed. The respective type strains are LMG 20964T (=DSM 14868T), LMG 19488T (=DSM 14866T) and LMG 19492T (= DSM 14867T). Finally, an emended description of the genus Virgibacillus is given.

Evaluation of ribosomal RNA gene restriction patterns for the classification of Bacillus species and related genera

AIMS

To identify Bacillus species and related genera by fingerprinting based on ribosomal RNA gene restriction patterns; to compare ribosomal RNA gene restriction patterns-based phylogenetic trees with trees based on 16S rRNA gene sequences; to evaluate the usefulness of ribosomal RNA gene restriction patterns as a taxonomic tool for the classification of Bacillus species and related genera.

METHODS AND RESULTS

Seventy-eight bacterial species which include 42 Bacillus species, 31 species from five newly created Bacillus-related genera, and five species from five phenotypically related genera were tested. A total of 77 distinct 16S rRNA gene hybridization banding patterns were obtained. The dendrogram resulting from UPGMA analysis showed three distinct main genetic clusters at the 75% banding pattern similarity. A total of 77 distinct 23S and 5S rRNA genes hybridization banding patterns were obtained, and the dendrogram showed four distinct genetic clusters at the 75% banding pattern similarity. A third dendrogram was constructed using a combination of the data from the 16S rRNA gene fingerprinting and the 23S and 5S rRNA genes fingerprinting. It revealed three distinct main phylogenetic clusters at the 75% banding pattern similarity.

CONCLUSIONS

The Bacillus species along with the species from related genera were identified successfully and differentiated by ribosomal RNA gene restriction patterns, and most were distributed with no apparent order in various clusters on each of the three dendrograms.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our data indicate that ribosomal RNA gene restriction patterns can be used to reconstruct the phylogeny of the Bacillus species and derived-genera that approximates, but does not duplicate, phylogenies based on 16S rRNA gene sequences.

A polyphasic taxonomic study of thermophilic bacilli from a wide geographical area

Two hundred and thirty-four thermophilic Bacillus strains isolated from geographically widespread locations were examined by phenotypic characterisation followed by numerical analysis. The strains were distributed between eighteen cluster-groups which were subsequently evaluated in DNA base composition and DNA sequence homology studies. The inclusion of type and reference strains unambiguously identified strains related to B. licheniformis, B. pallidus, B. smithii, B. stearothermophilus, B. thermocloacae and B. thermoglucosidasius. Other reference strains included in distinctive groups were 'B. caldotenax', together with 'B. caldovelox' and 'B. caldolyticus', B. kaustophilus and 'B. thermodenitrificans'. An emended description of B. kaustophilus is provided. It is proposed that 'B. caldotenax' and 'B. thermodenitrificans' should be accepted as validly described species. Members of other clusters that appeared to have distinctive characteristics, including beta-glucanase production and the ability to degrade tyrosine, may provide the nuclei of further novel species.

Suprageneric classification of thermoactinomyces vulgaris by nucleotide sequencing of 5S ribosomal RNA

The 5S rRNA nucleotide sequence of Thermoactinomyces vulgaris was determined and compared with published sequences of representative Gram-positive bacteria. The primary and secondary structure of the sequence is of the type characteristic of Gram-positive bacteria that have DNA with a low proportion of guanine plus cytosine. It was evident from the phylogenetic trees that T. vulgaris has little in common with actinomycetes but is related to the genus Bacillus, showing a moderately high relationship with B. stearothermophilus. The taxonomic implications of these relationships are discussed and an emended description of the family Bacillaceae is given.

Isolation and characterization of a Bacillus strain capable of degrading the extracellular glucan from Cellulomonas flavigena strain KU

Bacteria capable of utilizing the water-insoluble purified extracellular (1-->3)-beta-D-glucan (curdlan) from Cellulomonas flavigena strain KU by extracellular enzymes, were isolated and characterized. Enrichment cultures from a Winogradsky column were incubated anaerobically at 55 degrees C with curdlan as the sole source of carbon. Colonies surrounded by zones of clearing were selected from subcultures on solid curdlan media. One of the isolates was chosen for further study and identified by conventional methods, API-tests with calculation of similarity coefficients and ID-scores, estimation of mol% (G+C) and DNA-DNA liquid hybridization. The isolate is a facultatively anaerobic, facultatively thermophilic Bacillus sp. Identification at the species-level was not achieved. The isolate was characterized by some rare traits among bacilli, but it remains unresolved whether it defines a new taxon.

Sequences and homology analysis of two genes encoding beta-glucosidases from Bacillus polymyxa

The nucleotide sequences of the bglA and bglB genes encoding beta-glucosidases from Bacillus polymyxa have been determined. Both genes contain coding regions of 1344 bp, corresponding to polypeptides with Mrs of 51,643 and 51,547, respectively. Patterns of codon usage indicate that both genes are expressed at a low frequency. Previous data suggested that the proteins encoded by bglA and bglB were intra- and extracellular enzymes, respectively; however, neither of the two deduced amino acid sequences has N termini with the typical features of a leader peptide. The proteins encoded by bglA and bglB show remarkable homology to each other and to other beta-glucosidases (Bgl) and beta-galactosidases (beta Gal). On the basis of the observed homologies, we can define two groups of microbial Bgl: one of them, type I, including most bacterial Bgl, and type II, including enzymes from different yeast species and one from Clostridium thermocellum. Likewise, at least two groups of beta Gal can be distinguished: type I, including enzymes homologous to type-I Bgl, and type II, showing no homology to any of the previous groups.

Codon usage in selected AT-rich bacteria

The relationship between DNA base composition and codon bias in very AT-rich bacteria was analyzed. Five clostridial genes, five mycoplasmal genes and three rickettsial genes constituted the data base. In the genes of these three organisms, the rule for codon bias was very simple: use U or A in the first and third positions of the codon when possible. This was contrasted with the bias found in Bacillus subtilis and Escherichia coli. The rule for Bacillus subtilis was equally straightforward: use all codons without bias. Only in E. coli, amongst the species examined, did the codon bias appear to be a complicated codon 'choice'.