Bacillus ligniniphilus sp. nov., an alkaliphilic and halotolerant bacterium isolated from sediments of the South China Sea

Microbial induce carbonate precipitation derive bio-concrete formation: A sustainable solution for carbon sequestration and eco-friendly construction

The microbial-induced calcium carbonate precipitation (MICP) technique has high potential in the development of bio-concrete, enhancing the strength, durability, and self-healing properties of construction materials. In this review work, we have explored the crucial role of microorganisms in carbon sequestration, microbial methods in CaCO3 synthesis, and the application of bio-concrete formation, based on the SCOPUS database from 2010 to 2024. The production of construction materials consumes a significant amount of energy, which can emit high amounts of carbon dioxide (CO2) into the atmosphere. As a sustainable solution, researchers are working to introduce novel construction biomaterials through MICP, which play a key role in CO2 sequestration to address this issue. Herein, microorganisms (bacteria) can utilize CO2 through multiple absorption processes, converting it into value-added compounds or inducing CaCO3 precipitation. For example, specific bacteria like Bacillus cereus, Bacillus sphaericus, Bacillus pasteurii, Bacillus subtilis, and Bacillus megatherium are known for their capability to thrive in alkaline conditions and play a key role in bio-concrete formation. Furthermore, it has been highlighted that the bio-concrete ability to sequester CO2 through the carbonation process, emphasizes the roles of urease activity and carbonic anhydrase (CA) in bio-concrete. Overall, this paper provides a complete synopsis of recent research on the formation of bio-concrete through MICP and the various elements influencing the technique, including cementation solution, temperature, injection, pH, and bacteria. This suggests that emerging trends in bio-concrete utilization could significantly reduce CO2 emissions while enhancing the strength of non-reinforced concrete.

Elucidating the bioremediation potential of laccase and peroxidase enzymes from Bacillus ligniniphilus L1 in antibiotic degradation: A computationally guided study

This study showcased the antibiotic degradation abilities of laccase and catalase-peroxidase from Bacillus ligniniphilus L1, an extremophile, against 18 common antibiotics using computationally guided approach. Molecular docking and simulation identified six enzyme-antibiotic complexes for laccase and four for catalase-peroxidase, demonstrating significant binding affinity and stability. Enzyme activity assays corroborated computational results, indicating both enzymes could degrade all tested antibiotics with varying efficiencies. L1 laccase outperformed commercial laccase against five antibiotics, notably vancomycin, levofloxacin, tobramycin, linezolid, and rifamycin, with enhanced degradation potential upon ABTS addition. Catalase-peroxidase from L1 exhibited superior degradation efficiency over commercial peroxidase against vancomycin, linezolid, tobramycin, and clindamycin. Overall, this study underscores the computational approach's utility in understanding enzyme-mediated antibiotic degradation, offering insights into environmental contaminant remediation.

Evaluating the estrogen degradation potential of laccase and peroxidase from Bacillus ligniniphilus L1 through integrated computational and experimental approaches

This study investigated the degradation potential of laccase and catalase-peroxidase from the extremophilic marine bacterium Bacillus ligniniphilus L1 against endogenous and synthetic estrogen compounds using an integrated computational and experimental approach. Molecular docking identified five estrogen compounds exhibiting reliable bindings with enzymes, which were then subjected to enzyme activity assays. The degradation potential of the two enzymes against five selected estrogen compounds were investigated and compared with their commercial counterparts. Laccase from L1 showed higher degradation potential against estrone (47.02 % without and 62.21 % with ABTS) compared to commercial laccase (39 % without and 54.20 % with ABTS). For estradiol valerate, commercial laccase showed a slightly higher degradation (52.47 %) than L1 laccase (49.94 %), but with ABTS, L1 laccase performed better (74.15 % vs. 68.03 %). Notably, L1 catalase-peroxidase demonstrated significantly higher degradation for all tested compounds compared to its commercial counterpart with efficiencies of 96.16 %, 89.09 %, 74.94 %, 64.91 %, and 62.80 % against estropipate, quinestrol, estradiol valerate, estriol and estrone, respectively, revealing its potential for commercial applications. Molecular dynamics simulations revealed the interaction and stability of enzyme-estrogen complexes, with MMGBSA binding energy calculations supporting experimental results. These findings highlight the usefulness of the computational approach in elucidating the molecular mechanisms underlying enzyme-mediated bioremediation of environmental contaminants.

Evaluation of compost quality and the environmental effects of semipermeable membrane composting with poultry manure using sawdust or mushroom residue as the bulking agent

Herein, the effects of different bulking agents (sawdust and mushroom residue), on compost quality and the environmental benefits of semipermeable film composting with poultry manure were investigated. The results show that composting with sawdust as the bulking agent resulted in greater efficiency and more cost benefits than composting with mushroom residue, and the cost of sawdust for treating an equal volume of manure was only 1/6 of that of mushroom residue. Additionally, lignin degradation and potential carbon emission reduction in the sawdust group were better than those in the mushroom residue group, and the lignin degradation efficiency of the bottom sample in the sawdust group was 48.57 %. Coupling between lignin degradation and potential carbon emission reduction was also closer in sawdust piles than in mushroom residue piles, and sawdust is more environmentally friendly. The abundance of key functional genes was higher at the bottom of each pile relative to the top and middle. Limnochordaceae, Lactobacillus and Enterococcus were the core microorganisms involved in coupling between lignin degradation and potential carbon emission reduction, and the coupled relationship was influenced by electric conductivity, ammonia nitrogen and total nitrogen in the compost piles. This study provides important data for supporting bulking agent selection in semipermeable film composting and for improving the composting process. The results have high value for compost production and process application.

Optimization of heterologous production of Bacillus ligniniphilus L1 laccase in Escherichia coli through statistical design of experiments

Laccases are powerful multi-copper oxidoreductases that have wide applicability as "green" biocatalysts in biotechnological, bioremediation, and industrial applications. Sustainable production of large amounts of functional laccases from original sources is limited by low yields, difficulties in purification, slow growth of the organisms, and high cost of production. Harnessing the full potential of these versatile biocatalysts will require the development of efficient heterologous systems that allow high-yield, scalable, and cost-effective production. We previously cloned a temperature- and pH-stable laccase from Bacillus ligniniphilus L1 (L1-lacc) that demonstrated remarkable activity in the oxidation of lignin and delignification for bioethanol production. However, L1-lacc is limited by low enzyme yields in both the source organism and heterologous systems. Here, to improve production yields and lower the cost of production, we optimized the recombinant E. coli BL21 strain for high-level production of L1-lacc. Several culture medium components and fermentation parameters were optimized using one-factor-at-a-time (OFAT) and Plackett-Burman design (PBD) to screen for important factors that were then optimized using response surface methodology (RSM) and an orthogonal design. The optimized medium composition had compound nitrogen (15.6 g/L), glucose (21.5 g/L), K2HPO4 (0.15 g/L), MgSO4 (1 g/L), and NaCl (7.5 g/L), which allowed a 3.3-fold yield improvement while subsequent optimization of eight fermentation parameters achieved further improvements to a final volumetric activity titer of 5.94 U/mL in 24 h. This represents a 7-fold yield increase compared to the initial medium and fermentation conditions. This work presents statistically guided optimization strategies for improving heterologous production of a bacterial laccase that resulted in a high-yielding, cost-efficient production system for an enzyme with promising applications in lignin valorization, biomass processing, and generation of novel composite thermoplastics.

Phylogenetic survey of the subtilase family and a data-mining-based search for new subtilisins from Bacillaceae

The subtilase family (S8), a member of the clan SB of serine proteases are ubiquitous in all kingdoms of life and fulfil different physiological functions. Subtilases are divided in several groups and especially subtilisins are of interest as they are used in various industrial sectors. Therefore, we searched for new subtilisin sequences of the family Bacillaceae using a data mining approach. The obtained 1,400 sequences were phylogenetically classified in the context of the subtilase family. This required an updated comprehensive overview of the different groups within this family. To fill this gap, we conducted a phylogenetic survey of the S8 family with characterised holotypes derived from the MEROPS database. The analysis revealed the presence of eight previously uncharacterised groups and 13 subgroups within the S8 family. The sequences that emerged from the data mining with the set filter parameters were mainly assigned to the subtilisin subgroups of true subtilisins, high-alkaline subtilisins, and phylogenetically intermediate subtilisins and represent an excellent source for new subtilisin candidates.

Current Advances in Microbial Production of Acetoin and 2,3-Butanediol by Bacillus spp

The growing need for industrial production of bio-based acetoin and 2,3-butanediol (2,3-BD) is due to both environmental concerns, and their widespread use in the food, pharmaceutical, and chemical industries. Acetoin is a common spice added to many foods, but also a valuable reagent in many chemical syntheses. Similarly, 2,3-BD is an indispensable chemical on the platform in the production of synthetic rubber, printing inks, perfumes, antifreeze, and fuel additives. This state-of-the-art review focuses on representatives of the genus Bacillus as prospective producers of acetoin and 2,3-BD. They have the following important advantages: non-pathogenic nature, unpretentiousness to growing conditions, and the ability to utilize a huge number of substrates (glucose, sucrose, starch, cellulose, and inulin hydrolysates), sugars from the composition of lignocellulose (cellobiose, mannose, galactose, xylose, and arabinose), as well as waste glycerol. In addition, these strains can be improved by genetic engineering, and are amenable to process optimization. Bacillus spp. are among the best acetoin producers. They also synthesize 2,3-BD in titer and yield comparable to those of the pathogenic producers. However, Bacillus spp. show relatively lower productivity, which can be increased in the course of challenging future research.

Alkalihalobacterium elongatum gen. nov. sp. nov.: An Antibiotic-Producing Bacterium Isolated From Lonar Lake and Reclassification of the Genus Alkalihalobacillus Into Seven Novel Genera

A Gram-stain positive, long, rod-shaped, motile, and spore-forming bacterium (MEB199T) was isolated from a sediment sample collected from Lonar Lake, India. The strain was oxidase and catalase positive. The strain grew optimally at pH 10, NaCl concentration of 3.5% at 37°C. The major fatty acids were iso-C15:0, iso-C16:0, anteiso-C15:0, and iso-C17:0. The peptidoglycan contained meso-diaminopimelic acid (meso-DAP). Phosphatidylethanolamine, diphosphatidylglycerol, and phosphatidylglycerol were the major polar lipids of MEB199T. Phylogenetic analysis based on 16S rRNA gene sequence showed that strain MEB199T belonged to the family Bacillaceae and exhibited a distinctive position among the members of the genus Alkalihalobacillus (Ahb.). Strain MEB199T shared the highest 16S rRNA gene sequence similarity with Alkalihalobacillus alkalinitrilicus ANL-iso4T (98.36%), whereas with type species Ahb. alcalophilus DSM 485T, it is 94.91%, indicating that strain MEB199T is distinctly related to the genus Alkalihalobacillus. The G + C content of genomic DNA was 36.47 mol%. The digital DNA-DNA hybridization (dDDH) (23.6%) and average nucleotide identity (ANI) (81%) values between strain MEB199T and Ahb. alkalinitrilicus ANL-iso4T confirmed the novelty of this new species. The pairwise identity based on the 16S rRNA gene sequence between the species of genus Alkalihalobacillus ranges from 87.4 to 99.81% indicating the heterogeneity in the genus. The different phylogenetic analysis based on the genome showed that the members of the genus Alkalihalobacillus separated into eight distinct clades. The intra-clade average amino acid identity (AAI) and percentage of conserved proteins (POCP) range from 52 to 68% and 37 to 59%, respectively, which are interspersed on the intra-genera cutoff values; therefore, we reassess the taxonomy of genus Alkalihalobacillus. The phenotypic analysis also corroborated the differentiation between these clades. Based on the phylogenetic analysis, genomic indices, and phenotypic traits, we propose the reclassification of the genus Alkalihalobacillus into seven new genera for which the names Alkalihalobacterium gen. nov., Halalkalibacterium gen. nov., Halalkalibacter gen. nov., Shouchella gen. nov., Pseudalkalibacillus gen. nov., Alkalicoccobacillus gen. nov., and Alkalihalophilus gen. nov. are proposed and provide an emended description of Alkalihalobacillus sensu stricto. Also, we propose the Ahb. okuhidensis as a heterotypic synonym of Alkalihalobacillus halodurans. Based on the polyphasic taxonomic analysis, strain MEB199T represents a novel species of newly proposed genus for which the name Alkalihalobacterium elongatum gen. nov. sp. nov. is proposed. The type strain is MEB199T (= MCC 2982T, = JCM 33704T, = NBRC 114256T, = CGMCC 1.17254T).

Comparative genomic and secretomic characterisation of endophytic Bacillus velezensis LC1 producing bioethanol from bamboo lignocellulose

Bacillus is an excellent organic matter degrader, and it has exhibited various abilities required for lignocellulose degradation. Several B. velezensis strains encode lignocellulosases, however their ability to efficiently transform biomass has not been appreciated. In the present study, through the comparative genomic analysis of the whole genome sequences of 21 B. velezensis strains, CAZyome related to lignocellulose degradation was identified and their similarities and differences were compared. Subsequently, the secretome of B. velezensis LC1 by liquid chromatography-tandem mass spectrometry (LC-MS/MS) were identified and confirmed that a considerable number of proteins were involved in lignocellulose degradation. Moreover, after 6-day treatment, the degradation efficiency of the B. velezensis LC1 toward cellulose, hemicellulose and lignin were 59.90%, 75.44% and 23.41%, respectively, the hydrolysate was subjected to ethanol fermentation with Saccharomyces cerevisiae and Escherichia coli KO11, yielded 10.44 g/L ethanol after 96 h. These results indicate that B. velezensis LC1 has the ability to effectively degrade bamboo lignocellulose and has the potential to be used in bioethanol production.

Decoding lignin valorization pathways in the extremophilicBacillus ligniniphilusL1 for vanillin biosynthesis

An efficient bioconversion procedure for the accumulation of vanillin from lignin by pathway engineering and milking fermentation has been developed.

Acidic Versus Alkaline Bacterial Degradation of Lignin Through Engineered Strain E. coli BL21(Lacc): Exploring the Differences in Chemical Structure, Morphology, and Degradation Products

There is increasing interest in research on lignin biodegradation compounds as potential building blocks in applications related to renewable products. More attention is necessary to evaluate the effects of the initial pH conditions during the bacterial degradation of lignin. In this study we performed experiments on lignin biodegradation under acidic and mild alkaline conditions. For acidic biodegradation, lignin was chemically pretreated with hydrogen peroxide. Alkaline biodegradation was achieved by developing the bacterial growth on Luria and Bertani medium with alkali lignin as the sole carbon source. The mutant strain Escherichia coli BL21(Lacc) was used to carry out lignin biodegradation over 10 days of incubation. Results demonstrated that under acidic conditions there was a predominance of aliphatic compounds of the C3-C4 type. Alkaline biodegradation was produced in the context of oxidative stress, with a greater abundance of aryl compounds. The final pH values of acidic and alkaline biodegradation of lignin were 2.53 and 7.90, respectively. The results of the gas chromatography mass spectrometry analysis detected compounds such as crotonic acid, lactic acid and 3-hydroxybutanoic acid for acidic conditions, with potential applications for adhesives and polymer precursors. Under alkaline conditions, detected compounds included 2-phenylethanol and dehydroabietic acid, with potential applications for perfumery and anti tumor/anti-inflammatory medications. Size-exclusion chromatography analysis showed that the weight-average molecular weight of the alkaline biodegraded lignin increased by 6.75-fold compared to the acidic method, resulting in a repolymerization of its molecular structure. Lignin repolymerization coincided with an increase in the relative abundance of dehydroabietic acid and isovanillyl alcohol, from 2.70 and 3.96% on day zero to 13.43 and 10.26% on 10th day. The results of the Fourier-transformed Infrared spectroscopy detected the presence of C = O bond and OH functional group associated with carboxylic acids in the acidic method. In the alkaline method there was a greater preponderance of signals related to skeletal aromatic structures, the amine functional group and the C - O - bond. Lignin biodegradation products from E. coli BL21(Laccase), under different initial pH conditions, demonstrated a promising potential to enlarge the spectrum of renewable products for biorefinery activities.

A phylogenomic and comparative genomic framework for resolving the polyphyly of the genus Bacillus: Proposal for six new genera of Bacillus species, Peribacillus gen. nov., Cytobacillus gen. nov., Mesobacillus gen. nov., Neobacillus gen. nov., Metabacillus gen. nov. and Alkalihalobacillus gen. nov

The genus Bacillus, harbouring 293 species/subspecies, constitutes a phylogenetically incoherent group. In the absence of reliable means for grouping known Bacillus species into distinct clades, restricting the placement of new species into this genus has proven difficult. To clarify the evolutionary relationships among Bacillus species, 352 available genome sequences from the family Bacillaceae were used to perform comprehensive phylogenomic and comparative genomic analyses. Four phylogenetic trees were reconstructed based on multiple datasets of proteins including 1172 core Bacillaceae proteins, 87 proteins conserved within the phylum Firmicutes, GyrA-GyrB-RpoB-RpoC proteins, and UvrD-PolA proteins. All trees exhibited nearly identical branching of Bacillus species and consistently displayed six novel monophyletic clades encompassing 5-23 Bacillus species (denoted as the Simplex, Firmus, Jeotgali, Niacini, Fastidiosus and Alcalophilus clades), interspersed with other Bacillaceae species. Species from these clades also generally grouped together in 16S rRNA gene trees. In parallel, our comparative genomic analyses of Bacillus species led to the identification of 36 molecular markers comprising conserved signature indels in protein sequences that are specifically shared by the species from these six observed clades, thus reliably demarcating these clades based on multiple molecular synapomorphies. Based on the strong evidence from multiple lines of investigations supporting the existence of these six distinct 'Bacillus' clades, we propose the transfer of species from these clades into six novel Bacillaceae genera viz. Peribacillus gen. nov., Cytobacillus gen. nov., Mesobacillus gen. nov., Neobacillus gen. nov., Metabacillus gen. nov. and Alkalihalobacillus gen. nov. These results represent an important step towards clarifying the phylogeny/taxonomy of the genus Bacillus.

Bacillus shivajii sp. nov., isolated from a water sample of Sambhar salt lake, India

A novel Gram-stain-positive, rod-shaped, motile, spore-forming, strictly aerobic, alkali- and halo- tolerant bacterium, designated strain AK72^T, was isolated from a water sample collected from Sambhar salt lake, Rajasthan, India. The colony appears circular, shiny, smooth, translucent or slightly pale in colour and convex with an entire margin after 48 h incubation at 37 °C with pH 9. Growth of the bacterium occurred at 10-42 °C (optimum, 25-37 °C), at salinities of 0.5-10 % (w/v) NaCl (optimum 3-5 % NaCl) and pH of 6-10 (optimum pH 9). Strain AK72^T was positive for oxidase, catalase, nitrate reductase, phenylalanine deaminase, ornithine decarboxylase, aesculinase, lipase and urease activities. The predominant fatty acids were iso-C15 : 0, anteiso-C15 : 0 and iso-C16 : 0 and the cell-wall peptidoglycan contained meso-diaminopimelic acid as the diagnostic diamino acid. The major polar lipids of the strain were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an unidentified aminophospholipid, three unidentified phospholipids and three unidentified lipids. The genomic DNA G+C content of the strain AK72^T was 36.8 mol%. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain AK72^T was closely related to Bacillus cellulosilyticus (96.5 %) and Bacillus vedderi (96.3 %), but the novel strain AK72^T formed a separate clade with Bacillus aurantiacus whereas B. cellulosilyticus and B. vedderi were clustered in a separate clade. The above data in combination with the phenotypic characteristics and phylogenetic data inferred that strain AK72^T represents a novel species of the genus Bacillus, for which the name Bacillusshivajii sp. nov. is proposed. The type strain is AK72^T (=MTCC 12636^T=KCTC 33981^T=JCM 32183^T).

Comparative genome analysis of Bacillus velezensis reveals a potential for degrading lignocellulosic biomass

Genomes of 24 sequenced Bacillus velezensis strains were characterized to identity shared and unique genes of lignocellulolytic enzymes and predict potential to degrade lignocellulose. All 24 strains had genes that encoded lignocellulolytic enzymes, with potential to degrade cellulose and hemicelluloses. Several lignocellulosic genes related to cellulose degradation were universally present, including one GH5 (endo-1,4-β-glucanase), one GH30 (glucan endo-1,6-β-glucosidase), two GH4 (6-phospho-β-glucosidase, 6-phospho-α-glucosidase), one GH1 (6-phospho-β-galactosidase), one GH16 (β-glucanase) and three GH32 (two sucrose-6-phosphate hydrolase and levanase). However, in the absence of gene(s) for cellobiohydrolase, it was predicted that none of the 24 strains would be able to directly hydrolyse cellulose. Regarding genes for hemicellulose degradation, four GH43 (1,4-β-xylosidase; except strain 9912D), one GH11 (endo-1,4-β-xylanase), three GH43 (two arabinan endo-1,5-α-L-arabinosidase and one arabinoxylan arabinofuranohydrolase), two GH51 (α-N-arabinofuranosidase), one GH30 (glucuronoxylanase), one GH26 (β-mannosidase) and one GH53 (arabinogalactan endo-1,4-β-galactosidase) were present. In addition, two PL1 (pectate lyase) and one PL9 (pectate lyase) with potential for pectin degradation were conserved among all 24 strains. In addition, all 24 Bacillus velezensis had limited representation of the auxiliary activities super-family, consistent with a limited ability to degrade lignin. Therefore, it was predicted that for these bacteria to degrade lignin, pretreatment of lignocellulosic substrates may be required. Finally, based on in silico studies, we inferred that Bacillus velezensis strains may degrade a range of polysaccharides in lignocellulosic biomasses.

Biodegradation of alkaline lignin by Bacillus ligniniphilus L1

BACKGROUND

Lignin is the most abundant aromatic biopolymer in the biosphere and it comprises up to 30% of plant biomass. Although lignin is the most recalcitrant component of the plant cell wall, still there are microorganisms able to decompose it or degrade it. Fungi are recognized as the most widely used microbes for lignin degradation. However, bacteria have also been known to be able to utilize lignin as a carbon or energy source. Bacillus ligniniphilus L1 was selected in this study due to its capability to utilize alkaline lignin as a single carbon or energy source and its excellent ability to survive in extreme environments.

RESULTS

To investigate the aromatic metabolites of strain L1 decomposing alkaline lignin, GC-MS analysis was performed and fifteen single phenol ring aromatic compounds were identified. The dominant absorption peak included phenylacetic acid, 4-hydroxy-benzoicacid, and vanillic acid with the highest proportion of metabolites resulting in 42%. Comparison proteomic analysis was carried out for further study showed that approximately 1447 kinds of proteins were produced, 141 of which were at least twofold up-regulated with alkaline lignin as the single carbon source. The up-regulated proteins contents different categories in the biological functions of protein including lignin degradation, ABC transport system, environmental response factors, protein synthesis, assembly, etc.

CONCLUSIONS

GC-MS analysis showed that alkaline lignin degradation of strain L1 produced 15 kinds of aromatic compounds. Comparison proteomic data and metabolic analysis showed that to ensure the degradation of lignin and growth of strain L1, multiple aspects of cells metabolism including transporter, environmental response factors, and protein synthesis were enhanced. Based on genome and proteomic analysis, at least four kinds of lignin degradation pathway might be present in strain L1, including a Gentisate pathway, the benzoic acid pathway and the β-ketoadipate pathway. The study provides an important basis for lignin degradation by bacteria.

Halophiles: biology, adaptation, and their role in decontamination of hypersaline environments

The unique cellular enzymatic machinery of halophilic microbes allows them to thrive in extreme saline environments. That these microorganisms can prosper in hypersaline environments has been correlated with the elevated acidic amino acid content in their proteins, which increase the negative protein surface potential. Because these microorganisms effectively use hydrocarbons as their sole carbon and energy sources, they may prove to be valuable bioremediation agents for the treatment of saline effluents and hypersaline waters contaminated with toxic compounds that are resistant to degradation. This review highlights the various strategies adopted by halophiles to compensate for their saline surroundings and includes descriptions of recent studies that have used these microorganisms for bioremediation of environments contaminated by petroleum hydrocarbons. The known halotolerant dehalogenase-producing microbes, their dehalogenation mechanisms, and how their proteins are stabilized is also reviewed. In view of their robustness in saline environments, efforts to document their full potential regarding remediation of contaminated hypersaline ecosystems merits further exploration.

Description of Leucobacter holotrichiae sp. nov., isolated from the gut of Holotrichia oblita larvae

A Gram-stain-positive bacterium, designated T14T, was isolated from the gut of Holotrichia oblita larvae and was subjected to a taxonomic study. The isolate was rod-shaped, aerobic, non-motile, non-spore-forming and yellow-pigmented. Phylogenetic analysis based on 16S rRNA gene sequence comparison indicated that the isolate is related to the genus Leucobacter. Its closest neighbours were the type strains 'Leucobacter kyeonggiensis' F3-P9 (96.8% 16S rRNA gene sequence similarity), Leucobacter celer NAL101T (96.2%) and Leucobacter chironomi DSM 19883T (95.5%). The DNA G+C content of strain T14T was 69.3 mol%, and DNA-DNA hybridization values with closely related strains were <32%. The predominant cellular fatty acids were anteiso-C15:0 (49.3%), iso-C16:0 (16.4%) and anteiso-C17:0 (16.8%). The major polar lipids were aminolipid, diphosphatidylglycerol, phosphatidylglycerol, phospholipid, phosphoglycolipid and unidentified glycolipids. The predominant respiratory quinone was MK-11. Based on these phylogenetic and phenotypic results, strain T14T can be clearly distinguished from all of the recognized species of the genus Leucobacter and is considered to represent a novel species of the genus Leucobacter. The name Leucobacter holotrichiae sp. nov. is proposed, with the type strain T14T (=DSM 28968T=JCM 30245T).

Bacillus ectoiniformans sp. nov., a halotolerant bacterium isolated from deep-sea sediments

A halotolerant, Gram-positive bacterium (strain NE-14T), which was isolated from sediment samples of the South China Sea, was subjected to a taxonomic study. Strain NE-14T grew well at wide temperature and pH ranges, 10.0-45.0 °C and pH 6-10, with an optimum at 30 °C and pH 8.0, respectively. Growth of strain NE-14T was observed at total salt concentrations of 0-10 % (w/v) with optimum at 2 % (w/v). Phylogenetic analysis based on 16S rRNA gene sequence comparison indicated that the isolate belongs to the genus Bacillus. Strain NE-14T was related most closely to Bacillus shackletonii LMG 18435T, Bacillus bataviensis LMG 21833T, Bacillus idriensis SMC 4352-2T and Bacillus drentensis LMG 21831T with 16S rRNA gene sequence similarities of 96.2, 95.9, 95.8 and 95.7 %, respectively. DNA-DNA hybridization between strain NE-14T and B. shackletonii LMG 18435T, B. bataviensis LMG 21833T, B. idriensis SMC 4352-2T and B. drentensis LMG 21831T gave reassociation values of about 27.4, 22.4, 16.4 and 15.9 %, respectively. The DNA G+C content of strain NE-14T was 39.2 mol%. The predominant isoprenoid quinone was menaquinone 7 (MK-7). The cell-wall peptidoglycan contained meso-diaminopimelic acid as the diagnostic diamino acid. The predominant cellular fatty acids of strain NE-14T were iso-C15 : 0 and anteiso-C15 : 0. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and phospholipid. Based on the phenotypic and phylogenetic characteristics, it is proposed that strain NE-14T be classified as representing a novel species of the genus Bacillus, for which the name Bacillus ectoiniformans sp. nov. is proposed. The type strain is NE-14T ( = DSM 28970T = JCM 30397T).

Bacillus caseinilyticus sp. nov., an alkali- and thermotolerant bacterium isolated from a soda lake

A novel Gram-stain-positive, rod-shaped, motile, endospore-forming and proteolytic bacterial strain, SPT, was isolated from Lonar soda lake, in India. On the basis of 16S rRNA gene sequence analysis it was identified as belonging to the class Firmibacteria and was most closely related to Bacillus cellulosilyticus DSM 2522T (96.7  %) and other members of the genus Bacillus ( < 95.9  %). Strain SPT was catalase- and oxidase-positive. The cell-wall peptidoglycan of strain SPT contained meso-diaminopimelic acid. Polar lipids included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, three phospholipids, two aminolipids and two unknown lipids. The predominant isoprenoid quinone was MK-7. Anteiso-C15 : 0 (26.8  %) was the predominant fatty acid and significant proportions (>5  %) of iso-C15 : 0 (20.9  %), C16 : 1ω7c alcohol (6.3  %), iso-C16 : 0 (6.3  %) and anteiso-C17 : 0 (5.3  %) were also detected in strain SPT. The DNA G+C content of strain SPT was 38.9 mol%. The results of phylogenetic, chemotaxonomic and biochemical tests allowed a clear differentiation of strain SPT from all other members of the genus Bacillus. Strain SPT represents a novel member of the genus Bacillus, for which the name Bacillus caseinilyticus sp. nov. is proposed. The type strain is SPT ( = MCC 2612T = JCM 30246T).

Description of Comamonas serinivorans sp. nov., isolated from wheat straw compost

A Gram-stain-negative bacterium, designated SP-35(T), was isolated from compost and was subjected to a taxonomic study. This isolate was short-rod-shaped and non-spore-forming. Phylogenetic analysis based on 16S rRNA sequence comparison indicated the isolate was related to the genus Comamonas. 16S rRNA gene sequence analysis showed that its closest neighbours were the type strains Comamonas odontotermitis Dant 3-8(T) (96.8 % similarity), Comamonas testosteroni DSM 50244(T) (96.5 %), Comamonas guangdongensis CY01(T) (95.9 %) and Comamonas composti YY287(T) (95.6 %). Using phylogenetic analysis, DNA-DNA hybridization, fatty acid composition data and a range of physiological and biochemical characteristics we could clearly distinguish strain SP-35(T) from type strains of the genus Comamonas. The genomic DNA G+C content of strain SP-35(T) was 63.1 mol%. The predominant cellular fatty acids were C16 : 0, C17 : 0 cyclo, summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c) and summed feature 8 (C18 : 1ω6c and/or C18 : 1ω7c). The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidlyglycerol. Differences in phenotypic and phylogenetic characteristics support the classification of strain SP-35(T) as a representative of a novel species in the genus Comamonas, for which the name Comamonas serinivorans sp. nov. is proposed. The type strain is SP-35(T) ( = DSM 26136(T) = JCM 18194(T)).