Bacterial diversity and bioprospecting for cold-active lipases, amylases and proteases, from culturable bacteria of kongsfjorden and Ny-alesund, Svalbard, Arctic

Microbial oases in the ice: A state-of-the-art review on cryoconite holes as diversity hotspots and their scientific connotations

Cryoconite holes, small meltwater pools on the surface of glaciers and ice sheets, represent extremely cold ecosystems teeming with diverse microbial life. Cryoconite holes exhibit greater susceptibility to the impacts of climate change, underlining the imperative nature of investigating microbial communities as an essential module of polar and alpine ecosystem monitoring efforts. Microbes in cryoconite holes play a critical role in nutrient cycling and can produce bioactive compounds, holding promise for industrial and pharmaceutical innovation. Understanding microbial diversity in these delicate ecosystems is essential for effective conservation strategies. Therefore, this review discusses the microbial diversity in these extreme environments, aiming to unveil the complexity of their microbial communities. The current study envisages that cryoconite holes as distinctive ecosystems encompass a multitude of taxonomically diverse and functionally adaptable microorganisms that exhibit a rich microbial diversity and possess intricate ecological functions. By investigating microbial diversity and ecological functions of cryoconite holes, this study aims to contribute valuable insights into the broader field of environmental microbiology and enhance further understanding of these ecosystems. This review seeks to provide a holistic overview regarding the formation, evolution, characterization, and molecular adaptations of cryoconite holes. Furthermore, future research directions and challenges underlining the need for long-term monitoring, and ethical considerations in preserving these pristine environments are also provided. Addressing these challenges and resolutely pursuing future research directions promises to enrich our comprehension of microbial diversity within cryoconite holes, revealing the broader ecological and biogeochemical implications. The inferences derived from the present study will provide researchers, ecologists, and policymakers with a profound understanding of the significance and utility of cryoconite holes in unveiling the microbial diversity and its potential applications.

Cold adapted Pseudomonas: ecology to biotechnology

The cold adapted microorganisms, psychrophiles/psychrotolerants, go through several modifications at cellular and biochemical levels to alleviate the influence of low temperature stress conditions. The low temperature environments depend on these cold adapted microorganisms for various ecological processes. The ability of the microorganisms to function in cold environments depends on the strategies directly associated with cell metabolism, physicochemical constrains, and stress factors. Pseudomonas is one among such group of microorganisms which is predominant in cold environments with a wide range of ecological and biotechnological applications. Bioformulations of Pseudomonas spp., possessing plant growth promotion and biocontrol abilities for application under low temperature environments, are well documented. Further, recent advances in high throughput sequencing provide essential information regarding the prevalence of Pseudomonas in rhizospheres and their role in plant health. Cold adapted species of Pseudomonas are also getting recognition for their potential in biodegradation and bioremediation of environmental contaminants. Production of enzymes and bioactive compounds (primarily as an adaptation mechanism) gives way to their applications in various industries. Exopolysaccharides and various biotechnologically important enzymes, produced by cold adapted species of Pseudomonas, are making their way in food, textiles, and pharmaceuticals. The present review, therefore, aims to summarize the functional versatility of Pseudomonas with particular reference to its peculiarities along with the ecological and biotechnological applications.

Long-range transport of airborne bacteria over East Asia: Asian dust events carry potentially nontuberculous Mycobacterium populations

The nontuberculous mycobacterial pulmonary disease (NTM-PD) caused by Mycobacterium species has increased in prevalence all over the world. The distributions of NTM-PD are possibly determined by the westerly wind traveling at high altitudes over East Asia. However, the long-range transport of Mycobacterium species has not been demonstrated by analyzing the bacterial communities in aerosols such as desert mineral particles and anthropogenic pollutants transported by the westerly wind. Here, airborne bacterial compositions were investigated including Mycobacterium species in high-elevation aerosols, which were captured in the snow cover at 2,450 m altitude on Mt. Tateyama. This was further compared to the ground-level or high-altitude aerosols collected at six sampling sites distributed from Asian-dust source region (Tsogt-Ovoo) to downwind areas in East Asia (Asian continental cities; Erenhot, Beijing, Yongin, Japanese cities; Yonago, Suzu, Noto Peninsula). The cell concentrations and taxonomic diversities of airborne bacteria decreased from the Asian continent to the Japan area. Terrestrial bacterial populations belonging to Firmicutes and Actinobacteria showed higher relative abundance at high-elevation and Japanese cities. Additionally, Mycobacterium species captured in the snow cover on Mt. Tateyama increased in relative abundance in correspondence to the increase of black carbon concentrations. The relative abundance of Mycobacterium sequences was higher in the aerosol samples of Asian continental cities and Japanese cities than in the desert area. Presumably, anthropogenic pollution over East Asia carries potential Mycobacterium species, which induce NTM-PD, thereby impacting upon the public health.

Isolation, purification, and characterization of a novel exopolysaccharide isolated from marine bacteria Brevibacillus borstelensis M42

Marine microbes produce polysaccharides with unique physicochemical and functional properties that help them survive in harsh marine environments. However, only a handful of marine exopolysaccharides (EPSs) have been reported to date. The present study explored the seashore of Visakhapatnam, India, to report a novel exopolysaccharide designated as Br42 produced by Brevibacillus borstelensis M42. The isolate was identified through morphological, biochemical, phylogenetic, and genome sequencing analysis. The studies on fermentation kinetics revealed that EPS Br42 was a primary metabolite with a maximum production of 1.88 ± 0.02 g/L after 60 h when production broth was fortified with 2% glucose. Additionally, EPS Br42 was found to be a heteropolysaccharide consisting of glucose and galacturonic acid with a molecular weight of about 286 kDa. Interestingly, this molecule possesses industrially relevant functional properties such as water-holding (510 ± 0.35%), oil-holding (374 ± 0.12% for coconut oil and 384 ± 0.35% for olive oil), and swelling capacities (146.6 ± 5.75%). EPS Br42 could form an emulsion that was stable at a wide pH range for about 72 h and, in fact, performed better as compared to Span 20, a commercially used synthetic emulsifier. Moreover, this EPS was also found to be heat stable and exhibited non-Newtonian pseudoplastic behavior. These physicochemical and functional properties of polysaccharides suggest that the EPS Br42 has potential for multifarious industrial applications as an emulsifier, stabilizer, viscosifier, and binding agent.

Culturable Bacterial Isolates from Arctic Soil shows High Biotechnological Potential

Polar microbiology remains as the most fascinating area of research which mainly focuses on exploration of psychrophilic organisms for having their cold-active enzymes of biotechnological potential. In this study, we have explored a culturable bacterial community and isolated 27 bacterial isolates with a different morphology from an unexplored site of Arctic region, for the possibility of identifying various active biomolecules. Screening of various isolates in a culture dependent manner helped us to identify strains capable of producing extracellular enzymes. The optimal growth parameters of most of the isolates are ranges between 18-22°C temperature, 3-5 days of incubation, 6-9 pH, and 3-5% (w/v) NaCl in LB media. It has also been found that among these isolates, 63% are able to produce lipase, 17% amylase, 7% xylanase and 7% isolates have responded for phosphatase activity but there are no isolates found for gelatinase and cellulase production ability. In addition, few isolates can also produce secretory protease, urease, β-galactosidase, etc. 16SrRNA gene sequence-based phylogeny revealed that the isolates belong to the genera of Psychrobacter, Planococcus, Halomonas, Arthrobacter, Oceanisphaera, Marinbacter, Pseudomonas, Algoriphagus. Strikingly, none of the Arctic isolates showed resistance towards commonly used antibiotics which indicates that the unexplored habitat is devoid of antibiotic exposure and so does the rise of antimicrobial resistance. The structure-function relationship of the isolated bioactive compounds from these isolates are the major focus of future research.

Production of extracellular lipase from psychrotrophic bacterium Oceanisphaera sp. RSAP17 isolated from arctic soil

Cold-active extracellular lipases produced by different psychrotrophs are important for various industrial applications. We have isolated a Gram-negative, rod-shaped, aerobe, non-pigment producing psychrotrophic bacterial strain RSAP17 (MTCC 12991, MCC 4275) from the unexplored Arctic soil sample of NyAlesund, Svalbard, Norway (78° 55″ N, 11° 54″ E). The detailed morphological, biochemical, and molecular characteristics were investigated to characterize the isolate RSAP17. Analyses of the 16S rDNA sequence of strain RSAP17 (Accession no. MK391379) shows the closest match with Oceanisphaera marina YM319^T (99.45%) and Oceanisphaera sediminis TW92 JCM 17329^T (97.40%). The isolate is capable of producing extracellular lipase but not amylase, cellulase or urease. The optimal parameters for lipase production have been found in tributyrin based (10 mL/L) agar media supplemented with 3% (w/v) NaCl after 2-3 days of incubation at 20-22 °C temperature and pH 9 at shaking condition. We have purified the extracellular lipase from the RSAP17 grown culture supernatant through 75% ammonium sulfate precipitation followed by dialysis and DEAE cellulose column chromatography. The invitro lipolytic activity of the purified lipase enzymes has been done through zymogram analysis. The molecular weight found for the lipase is 103.8 kD. The optimal activity of the purified lipase has been found at 25 °C and pH 9. MALDI-TOF-MS study of the purified lipase showed the highest match with the sequence of prolipoprotein diacylglyceryl transferase with 44% sequence coverage. Further study on large-scale production, substrate utilization and enzymatic kinetics of this lipase could unravel its possibility in future biotechnological applications.

Prophage Genomics and Ecology in the Family Rhodobacteraceae

Roseobacters are globally abundant bacteria with critical roles in carbon and sulfur biogeochemical cycling. Here, we identified 173 new putative prophages in 79 genomes of Rhodobacteraceae. These prophages represented 1.3 ± 0.15% of the bacterial genomes and had no to low homology with reference and metagenome-assembled viral genomes from aquatic and terrestrial ecosystems. Among the newly identified putative prophages, 35% encoded auxiliary metabolic genes (AMGs), mostly involved in secondary metabolism, amino acid metabolism, and cofactor and vitamin production. The analysis of integration sites and gene homology showed that 22 of the putative prophages were actually gene transfer agents (GTAs) similar to a GTA of Rhodobacter capsulatus. Twenty-three percent of the predicted prophages were observed in the TARA Oceans viromes generated from free viral particles, suggesting that they represent active prophages capable of induction. The distribution of these prophages was significantly associated with latitude and temperature. The prophages most abundant at high latitudes encoded acpP, an auxiliary metabolic gene involved in lipid synthesis and membrane fluidity at low temperatures. Our results show that prophages and gene transfer agents are significant sources of genomic diversity in roseobacter, with potential roles in the ecology of this globally distributed bacterial group.

Metabolic activity of cryogenic soils in the subarctic zone of Siberia towards "green" bioplastics

The present study investigates, for the first time, the structure of the microbial community of cryogenic soils in the subarctic region of Siberia and the ability of the soil microbial community to metabolize degradable microbial bioplastic - poly-3-hydroxybutyrate [P(3HB)]. When the soil thawed, with the soil temperature between 5-7 and 9-11 °C, the total biomass of microorganisms at a 10-20-cm depth was 226-234 mg g^-1 soil and CO₂ production was 20-46 mg g^-1 day^-1. The total abundance of microscopic fungi varied between (7.4 ± 2.3) × 10³ and (18.3 ± 2.2) × 10³ CFU/g soil depending on temperature; the abundance of bacteria was several orders of magnitude greater: (1.6 ± 0.1) × 10⁶ CFU g^-1 soil. The microbial community in the biofilm formed on the surface of P(3HB) films differed from the background soil in concentrations and composition of microorganisms. The activity of microorganisms caused changes in the surface microstructure of polymer films, a decrease in molecular weight, and an increase in the degree of crystallinity of P(3HB), indicating polymer biodegradation due to metabolic activity of microorganisms. The clear-zone technique - plating of isolates on the mineral agar with polymer as sole carbon source - was used to identify P(3HB)-degrading microorganisms inhabiting cryogenic soil in Evenkia. Analysis of nucleotide sequences of rRNA genes was performed to identify the following P(3HB)-degrading species: Bacillus pumilus, Paraburkholderia sp., Pseudomonas sp., Rhodococcus sp., Stenotrophomonas rhizophila, Streptomyces prunicolor, and Variovorax paradoxus bacteria and the Penicillium thomii, P. arenicola, P. lanosum, Aspergillus fumigatus, and A. niger fungi.

The Variety and Inscrutability of Polar Environments as a Resource of Biotechnologically Relevant Molecules

The application of an ever-increasing number of methodological approaches and tools is positively contributing to the development and yield of bioprospecting procedures. In this context, cold-adapted bacteria from polar environments are becoming more and more intriguing as valuable sources of novel biomolecules, with peculiar properties to be exploited in a number of biotechnological fields. This review aims at highlighting the biotechnological potentialities of bacteria from Arctic and Antarctic habitats, both biotic and abiotic. In addition to cold-enzymes, which have been intensively analysed, relevance is given to recent advances in the search for less investigated biomolecules, such as biosurfactants, exopolysaccharides and antibiotics.

Novel xylanase producing Bacillus strain X2: molecular phylogenetic analysis and its application for production of xylooligosaccharides

A Bacillus strain X2 that produced extracellular endo-xylanase (GH 11) (EC: 3.2.1.8) was isolated from the soil of the Northeast India region. This aerobic culture was Gram positive and endospore forming. Chemotaxonomic characterization showed variance with the fatty acid profile of related species in the Bacillus subtilis group. In Bacillus strain X2, distinct occurrence of iso-C14:0 lipids is absent in other related species. The 16S rRNA gene sequence homology showed 99% similarity with Bacillus subtilis subsp. inaquosorum. The phylogenetic analysis by the multilocus sequence analysis (MLSA) of the nucleotide sequence of six concatenated genes (16S rRNA, groEL, gyrA, polC, purH and rpoB) resolved the taxonomic position of the Bacillus strain X2 in the Bacillus subtilis subsp. group. The MLSA showed that it is a member of a clade that includes Bacillus subtilis subsp. stercoris. In in silico DNA-DNA hybridization (DDH), the highest matching score was obtained with Bacillus subtilis subsp. stercoris (87%). The in silico DDH of the genome (G + C 43.7 mol %) shared 48.5%, with Bacillus subtilis subsp. inaquosorum. The MLSA phylogenetic tree and the highest degree of DNA hybridization, indicating that it belongs to the Bacillus subtilis subspecies stercoris.

Bacterial community structure of a glacio-marine system in the Arctic (Ny-Ålesund, Svalbard)

The bacterial community composition of a valley glacier in Svalbard, its pro-glacial channels, and the associated downstream fjord ecosystem was investigated so as to figure out the degree to which downslope transport of microbes from the glacier systems along a hydrological continuum impose an effect on the patterns of diversity in the fjord system. A combination of culture based and high-throughput amplicon sequencing approach was followed which resulted in significant variation (R = 0.873, p = 0.001) in the bacterial community structure between these ecosystems. Dominance of sequences belonging to class β-Proteobacteria was seen in the glacier snow, ice and melt waters (MW) while a relatively higher abundance of OTUs belonging to α-Proteobacteria and Verrucomicrobiae demarcated the fjord waters. Similarity percentage (SIMPER) analysis of the Operational Taxonomic Units (OTUs) showed that OTU 1,105,280 (9.15%) and OTU 331 (6.5%) belonging to Burkholderiaceae (β-proteobacteria) and OTU 101,660 (5.76%) and OTU 520 (5.07%) belonging to Rhodobacteraceae (α-proteobacteria) contributed maximum to the overall dissimilarity between the sampling sites. The bacterial community from the MWs were found to be true signatures of the glacier ecosystem while the Kongsfjorden bacterial fraction mostly represented heterotrophic marine taxa influenced by warm Atlantic waters and presence of organic matter. Significant presence of unknown taxa in the MWs suggests the need to study such unexplored, transient niches for a better understanding of the associated microbial processes. Among the various environmental parameters measured, nutrients (NO₃^- and SiO₄^2-) were found to exhibit strong association with the MW bacterial community while temperature, trace metals, Cl^- and SO₄^2- ions were found to influence the fjord bacterial community. The significant differences in the bacterial community composition between the glacier and the fjord ecosystem suggest the unique nature of these systems which in turn is influenced by the associated environmental parameters.

Salibacterium nitratireducens sp. nov., a haloalkalitolerant bacterium isolated from a water sample from Sambhar salt lake, India

A strictly aerobic, haloalkali-tolerant, Gram-stain-positive, non-motile, rod-shaped bacterium, designated strain SMB4^T, was isolated from a water sample collected from Sambhar salt lake, Rajasthan, India. Growth occurred at 25-50 °C, 4-12 % (w/v) NaCl and pH of 5-9. Strain SMB4^T was positive for β-galactosidase, oxidase, catalase and urease activities. The fatty acids were dominated by branched forms of fatty acids with iso- and anteiso-saturated fatty acids, with a high abundance of anteiso-C15 : 0, anteiso-C17 : 0 and C18 : 0. The cell-wall peptidoglycan of strain SMB4^T contained meso-diaminopimelic acid, while the polar lipids included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, one unidentified phospholipid and three unidentified lipids. The DNA G+C content of strain SMB4^T was 49.1 mol%. A blast sequence similarity search based on 16S rRNA gene sequence indicated that Salibacterium halochares, Salibacterium halotolerans and Salibacterium qingdaonense were the nearest phylogenetic neighbours, with a pair-wise sequence similarities of 98.4, 98.2 and 97.0 % respectively. Phylogenetic analysis showed that strain SMB4^T was clustered with S. halochares and together clustered with S. halotolerans and S. qingdaonense. DNA-DNA hybridization of strain SMB4^T with S. halochares DSM 21373^T, S. halotolerans S7^T and S. quigdaonense DSM 21621^T showed a relatedness values of only 39.8, 26.3 and 42.8 %, respectively. Based on its phenotypic characteristics and on phylogenetic inference, strain SMB4^T represents a novel species of the genus Salibacterium, for which the name Salibacterium nitratireducens sp. nov. is proposed. The type strain is SMB4^T (=MTCC 12633^T=KCTC 33876^T=JCM 32187^T).

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).

Characterization and Screening of Thermophilic Bacillus Strains for Developing Plant Growth Promoting Consortium From Hot Spring of Leh and Ladakh Region of India

In the present investigation, the main aim is to identify and characterize the potential drought tolerant plant growth promoting consortium for agricultural productivity. Three bacterial isolates were isolated from hot spring of Chumathang area of Leh district. Bacillus species (BHUJP-H1, BHUJP-H2, and BHUJP-H3) were done some biochemical tests including catalase, cellulase, amylase, indole-3-acetic acid, phosphate solubilisation, production of ammonia, siderophore, and hydrogen cyanide. Molecular characterization of isolates was done by 16S rDNA sequencing, e.g., Bacillus subtilis BHUJP-H1 (KU312403), Bacillus sp. BHUJP-H2 (KU312404) and B. licheniformis BHUJP-H3 (KU312405). The genetic diversity of the isolates was assessed by seven inter simple sequence repeat, all primer shows high polymorphism. The highest polymorphism efficiency and polymorphism information content showed by UBC-809 and UBC-836 which were 100% and 0.44 respectively, the lowest is by UBC-807 75% and 0.28 respectively. On an average 90.69% polymorphism efficiency and 0.40 polymorphism information contents obtained by used markers. The highest, 11.08 and the lowest, 4.50 effective multiplex ratios obtained for primer UBC-823 and UBC-807, on an average 7.99 effective multiplex ratio obtained. The highest, 4.89 and the lowest, 1.25 marker indexes obtained by UBC-836 and UBC-807 respectively and on an average 3.24 obtained. The UPGMA cluster analysis divided a population into two clusters I and II, in which BHUJP-H1 and BHUJP-H2 grouped under same while BHUJP-H3 grouped under another cluster. The treatment combination of Bacillus subtilis BHUJP-H1, B. subtilis BHUJP-H1+ B. licheniformis BHUJP-H3 and B. subtilis BHUJP-H1+ Bacillus sp. BHUJP-H2+ B. licheniformis BHUJP-H3 were recorded better combination for enhancing plant growth attributes of Vigna radiata as compared to control and others. The plant growth promoting consortium, e.g., Bacillus subtilis BHUJP-H1, Bacillus subtilis BHUJP-H1+ B. licheniformis BHUJP-H3 and B. subtilis BHUJP-H1+ Bacillus sp. BHUJP-H2+ B. licheniformis BHUJP-H3 can be further used as effective microbial inoculant for enhancing the production of mungbean in field conditions. Bacillus sp. BHUJP-H1 and Bacillus sp. BHUJP-H2 may use as drought tolerant plant growth promoting consortium for enhancing the sustainable agricultural productivity.

Bacterial community structure along the subtidal sandy sediment belt of a high Arctic fjord (Kongsfjorden, Svalbard Islands)

Open fjords are subject to contrasting environmental conditions, owing to meltwater glacial inputs, terrestrial runoff, and marine water mass exchanges, which are exacerbated by anthropogenic and climate perturbations. Following a slope-dependent water circulation, the subtidal sandy sediment belt regulates the convergent transport of nutrients downward the fjord depths, and the effective entrapment of suspended particles and microorganisms. In this study, we aimed at testing how glacial and seawater inputs may influence the bacterial community structure of subtidal sand deposits in the Kongsfjorden. Through total and viable cell counting and an amplicon sequencing approach, we found relevant differences in bacterial community structure along the glacio-marine sampling transect. Viable and high nucleic acid content (HNA) cells represented an important fraction of the total community, generally decreasing toward the glacier front. Besides the predominance of Alpha- and Gammaproteobacteria, Bacteroidetes, Firmicutes and Parcubacteria, the bacterial community structure was likely affected by the glacial activity in the inner fjord, with the occurrence of distinctive phylotypes belonging to Gemmatimonadates, Nitrospirae, Acidobacteria, and Chloroflexi. Overall, our outcomes highlighted that exploring the bacterial community distribution and structure can provide new insights into the active role of sand deposits in coastal cold environments.

Bacillus mangrovi sp. nov., isolated from a sediment sample from a mangrove forest

A facultatively anaerobic, endospore forming, alkali-tolerant, Gram-stain-positive, motile, rod-shaped bacterium, designated strain AK61T, was isolated from a sediment sample collected from Coringa mangrove forest, India. Colonies were circular, 1.5 mm in diameter, shiny, smooth, yellowish and convex with entire margins after 48 h growth at 30 °C. Growth occurred at 15-42 °C, with 0-3 % (w/v) NaCl and at pH 6-9. AK61T was positive for amylase activity and negative for oxidase, catalase, aesculinase, caseinase, cellulase, DNase, gelatinase, lipase and urease activities. The fatty acids were dominated by branched types with iso- and anteiso- saturated fatty acids with a high abundance of iso-C14 : 0, iso-C15 : 0, anteiso-C15 : 0 and iso-C16 : 0; the cell-wall peptidoglycan contained meso-diaminopimelic acid as the diagnostic diamino acid; and MK-7 was the major menaquinone. DNA-DNA hybridization between AK61T and Bacillus indicus MTCC 4374T and between AK61T and Bacillus indicus KCTC 3880 showed relatedness of 37.99 and 33.32 % respectively. The DNA G+C content of AK61T was 44 mol%. The results of a blast sequence similarity search based on 16S rRNA gene sequences indicated that Bacillus cibi and Bacillus indicus were the nearest phylogenetic neighbours, with a pair-wise sequence similarity of 97.69 and 97.55 % respectively. The results of phylogenetic analysis indicated that AK61T was clustered with Bacillus idriensis and Bacillus indicus. On the basis of its phenotypic characteristics and phylogenetic inference, AK61T represents a novel species of the genus Bacillus, for which the name Bacillus mangrovi sp. nov. is proposed. The type strain is AK61T (=JCM 31087T=MTCC 12015T=KCTC 33872T).

Agar-degrading bacteria isolated from Antarctic macroalgae

This study describes the taxonomic diversity of pigmented, agar-degrading bacteria isolated from the surface of macroalgae collected in King George Island, Antarctica. A total of 30 pigmented, agarolytic bacteria were isolated from the surface of the Antarctic macroalgae Adenocystis utricularis, Monostroma hariotii, Iridaea cordata, and Pantoneura plocamioides. Based on the 16S rRNA data, the agarolytic isolates were affiliated to the genera Algibacter, Arthrobacter, Brachybacterium, Cellulophaga, Citricoccus, Labedella, Microbacterium, Micrococcus, Salinibacterium, Sanguibacter, and Zobellia. Isolates phylogenetically related to Cellulophaga algicola showed the highest agarase activity in culture supernatants when tested at 4 and 37 °C. This is the first investigation of pigmented agar-degrading bacteria, members of microbial communities associated with Antarctic macroalgae, and the results suggest that they represent a potential source of cold-adapted agarases of possible biotechnological interest.

Diversity of retrievable heterotrophic bacteria in Kongsfjorden, an Arctic fjord

The diversity and abundance of retrievable pelagic heterotrophic bacteria in Kongsfjorden, an Arctic fjord, was studied during the summer of 2011 (June, August, and September). Retrievable bacterial load ranged from 10³ to 10⁷ CFU L⁻¹ in June, while it was 10⁴–10⁶ CFU L⁻¹ in August and September. Based on 16S rRNA gene sequence similarities, a higher number of phylotypes was observed during August (22 phylotypes) compared to that during June (6 phylotypes) and September (12 phylotypes). The groups were classified into four phyla: Firmicutes, Actinobacteria, Proteobacteria, and Bacteroidetes. Bacteroidetes was represented only by a single member Leewenhoekiella aequorea during the three months and was dominant (40%) in June. However, this dominance changed in August to a well-known phytopathogenic species Rhodococcus fascians (32%), which could be a result of decrease in the phytoplankton biomass following the secondary bloom. It is the first report of Halomonas titanicae isolation from the Arctic waters. It showed an increase in its abundance with the intrusion of Atlantic water into Kongsfjorden. Increased abundance of Psychrobacter species in the late summer months coincided with the presence of cooler waters. Thus, the composition and function of heterotrophic bacterial community was fundamentally different in different months. This could be linked to the changes in the water masses and/or phytoplankton bloom dynamics occurring in Arctic summer.

Spatio-Temporal Monitoring and Ecological Significance of Retrievable Pelagic Heterotrophic Bacteria in Kongsfjorden, an Arctic Fjord

Kongsfjorden is a glacial fjord in the Arctic that is influenced by both Atlantic and Arctic water masses. In the present report retrievable heterotrophic bacteria isolated from two distinct zones (outer and inner fjord) of Kongsfjorden was studied during summer to fall of 2012. 16S rRNA gene sequences of the retrievable heterotrophic bacteria corresponded to γ-proteobacteria (13 phylotypes), α-proteobacteria (3 phylotypes), Bacteroidetes (4 phylotypes) and Actinobacteria (2 phylotypes). The heterotrophic bacterial community structure was fundamentally different in different months which could be linked to changes in the water masses and/or phytoplankton bloom dynamics. It is hypothesized that monitoring the retrievable heterotrophic bacterial assemblage in the fjord would give valuable insights into the complex ecological role they play under extreme and dynamic conditions.

Metagenomic assessment of the microbial diversity in ground pork products from markets in the North Central Region of South Korea

The purpose of this study was to characterize the microbial community in ground pork using molecular approaches. Forty six ground pork products were purchased from local stores in the north central area of South Korea. Aerobic plate counts varied 4.23 ± 5.14 × 10(5) CFU/g with the range between 5.00 × 10(3) and 1.85 × 10(6) CFU/g for ground pork samples. Four ground meat samples were further processed for metagenomic analysis. Pseudomonas species was the most relative abundant with a wide range occurring (1.72 to 77.7%) as part of the microbial genera in ground pork. Bacteria such as Carnobacterium, Yersinia, Photobacterium were also identified in ground pork. Despite the prominence of certain genera across all samples there was still extensive microbial diversity among ground pork products that originated from different slaughter houses and were processed in different markets. Such diversity indicates that designing interventions to extend shelf life may be hampered by the extensive variability in the microbial consortia associated with pork products. However, this diversity may be useful for developing microbial traceability signatures unique to a slaughter house or a particular market.

Wide pH range tolerance in extremophiles: towards understanding an important phenomenon for future biotechnology

Microorganisms that inhabit the extreme pH environments are classified as acidophiles and alkaliphiles. A number of studies emerged from extreme high (hot springs, hydrothermal vents) as well as low temperature (arctic and antarctic regions, sea water, ice shelf, marine sediments, cold deserts, glaciers, temperate forests, and plantations) environments have highlighted the occurrence of microorganisms (thermophiles/psychrophiles) with the ability to tolerate wide pH range, from acidic to alkaline (1.5-14.0 in some cases), under laboratory conditions. However, the sampling source (soil/sediment) of these microorganisms showed the pH to be neutral or slightly acidic/alkaline. The aim of the present review is to discuss the phenomenon of wide pH range tolerance possessed by these microorganisms as a hidden character in perspective of their habitats, possible mechanisms, phylogeny, ecological and biotechnological relevance, and future perspectives. It is believed that the genome is a probable reservoir of the hidden variations. The extremophiles have the ability to adapt against the environmental change that is probably through the expression/regulation of the specific genes that were already present in the genome. The phenomenon is likely to have broad implications in biotechnology, including both environmental (such as bioremediation, biodegradation, and biocontrol), and industrial applications (as a source of novel extremozymes and many other useful bioactive compounds with wide pH range tolerance).

Tumebacillus lipolyticus sp. nov., isolated from river water

An aerobic, endospore-forming, alkali-tolerant, Gram-stain-positive, non-motile, rod-shaped bacterium, designated strain NIO-S10T, was isolated from a surface water sample collected from the Godavari River, Kapileswarapuram, India. Colonies on nutrient agar were circular, 3-4 mm in diameter, creamish and raised after incubation for 36 h at 37 °C. Growth occurred at 20-40 °C, at pH 6-9 and in the presence of 0-2 % (w/v) NaCl. Strain NIO-S10T was positive for oxidase, caseinase, DNase, gelatinase, lipase and urease activities, and negative for catalase, aesculinase, amylase and cellulase activities. The fatty acids were dominated by branched and saturated fatty acids, with a high abundance of iso-C15 : 0, anteiso-C15 : 0 and C18 : 0.The cell-wall peptidoglycan contained meso-diaminopimelic acid as the diagnostic diamino acid, and MK-7 was the major menaquinone. The DNA G+C content of strain NIO-S10T was 54.4 mol%. A blast sequence similarity search based on 16S rRNA gene sequences indicated that Tumebacillus ginsengisoli Gsoil 1105T was the nearest phylogenetic neighbour to strain NIO-S10T, with a pairwise sequence similarity of 94.9 %. Phylogenetic analysis showed that strain NIO-S10T was clustered with members of the genus Tumebacillus and together with members of the genus Effusibacillus. Based on phenotypic characteristics and phylogenetic inference, strain NIO-S10T represents a novel species of the genus Tumebacillus, for which the name Tumebacillus lipolyticus sp. nov. is proposed. The type strain is NIO-S10T ( = KCTC 32289T = MTCC 12483T).

Taxonomic characterization and the bio-potential of bacteria isolated from glacier ice cores in the High Arctic

Glacier ice and firn cores have ecological and biotechnological importance. The present study is aimed at characterizing bacteria in crustal ice cores from Svalbard, the Arctic. Counts of viable isolates ranged from 10 to 7000 CFU/ml (mean 803 CFU/ml) while the total bacterial numbers ranged from 7.20 × 10(4) to 2.59 × 10(7)  cells ml(-1) (mean 3.12 × 10(6)  cells ml(-1) ). Based on 16S rDNA sequence data, the identified species belonged to seven species, namely Bacillus barbaricus, Pseudomonas orientalis, Pseudomonas oryzihabitans, Pseudomonas fluorescens, Pseudomonas syncyanea, Sphingomonas dokdonensis, and Sphingomonas phyllosphaerae, with a sequence similarity ranging between 93.5 and 99.9% with taxa present in the database. The isolates exhibited unique phenotypic properties, and three isolates (MLB-2, MLB-5, and MLB-9) are novel species, yet to be described. To the best of our knowledge, this is the first report on characterization of cultured bacterial communities from Svalbard ice cores. We conclude that high lipase, protease, cellulase, amylase, and urease activities expressed by most of the isolates provide a clue to the potential industrial applications of these organisms. These microbes, producing cold-adapted enzymes may provide an opportunity for biotechnological research.

Marinobacter nitratireducens sp. nov., a halophilic and lipolytic bacterium isolated from coastal surface sea water

A novel Gram-stain-negative, rod-shaped, motile bacterium, designated strain AK21T, was isolated from coastal surface sea water at Visakhapatnam, India. The strain was positive for oxidase, catalase, lipase, l-proline arylamidase and tyrosine arylamidase activities. The predominant fatty acids were C12:0, C12:0 3-OH, C16:0, C16:1ω9c, C18:1ω9c and summed feature 3 (C16:1ω7c and/or iso-C15:0 2-OH). The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, one unidentified aminophospholipid, two unidentified phospholipids and one unidentified lipid. Q-10 was the predominant respiratory quinone. The DNA G+C content of the strain was 54.6 mol%. 16S rRNA gene sequence analysis indicated that strain AK21T was a member of the genus Marinobacter and was closely related to Marinobacter xestospongiae, with pairwise sequence similarity of 97.2 % to the type strain, with similarity to other members of the genus of 94.0–96.8 %. The mean DNA–DNA relatedness of strain AK21T with M. xestospongiae JCM 17469T was 34.5 %, and relatedness with Marinobacter mobilis JCM 15154T was 40.5 %. Phylogenetic analysis showed that strain AK21T clustered with the type strains of M. xestospongiae and M. mobilis at distances of 2.9 and 2.8 % (97.1 and 97.2 % similarity), respectively. Based on the phenotypic characteristics and on phylogenetic inference, it appears that strain AK21T represents a novel species of the genus Marinobacter, for which the name Marinobacter nitratireducens sp. nov. is proposed. The type strain of Marinobacter nitratireducens is AK21T ( = MTCC 11704T = JCM 18428T).

Diversity and bioprospective potential (cold-active enzymes) of cultivable marine bacteria from the subarctic glacial Fjord, Kongsfjorden

The diversity and abundance of culturable bacteria in Kongsfjorden water (15 stations) and sediments (12 stations) were studied. Viable numbers ranged between 105–106 CFU l−1 in water and 102–104 CFU g−1 in the sediments. A total of 291 and 43 bacterial isolates were retrieved from the water (KJF) and sediments (FS), respectively. Based on 16S rRNA gene sequence similarities, the KJF and FS isolates were grouped into 49 and 23 phylotypes, respectively. The KJF and FS phylotypes represented three phyla namely, Actinobacteria, Bacteroidetes, and Proteobacteria. At the genus level, Flavobacterium and Shewanella and at the species level, Pseudoaltermonas arctica and Colwellia psychrerythraea were dominant in the water and sediments, respectively. Most phylotypes were psychrotolerant with upper growth temperature limit of 25–37 °C and tolerated 0.3–2.5 M NaCl and pH values of 5.0–11.0. Majority of the phylotypes produced one or more of the extracellular hydrolytic enzymes amylase, lipase, caseinase, urease, gelatinase, and DNase at 4 and 18 °C, while none were chitinolytic. Few of the FS phylotypes exhibited extracellular activity only at 4 or 18 °C. Nine FS and 21 KJF isolates were pigmented. The predominant cellular fatty acids were unsaturated, branched, and modified fatty acids, which are unique to cold-adapted bacteria.

Diversity, cold active enzymes and adaptation strategies of bacteria inhabiting glacier cryoconite holes of High Arctic

Cryoconite holes have biogeochemical, ecological and biotechnological importance. This communication presents results on culturable psychrophilic bacterial diversity from cryoconite holes at Midre Lovénbreen (ML), Austre Brøggerbreen (AB), and Vestre Brøggerbreen (VB) glaciers. The culturable bacterial count ranged from 2.7 × 10(3) to 8.8 × 10(4) CFUs/g while the total bacterial numbers ranged from 5.07 × 10(5) to 1.50 × 10(6) cells at the three glaciers. A total of 35 morphologically distinct bacterial isolates were isolated. Based on 16S rRNA gene sequence data, the identified species belonged to eight genera namely Pseudomonas, Polaromonas, Micrococcus, Subtercola, Agreia, Leifsonia, Cryobacterium and Flavobacterium. The isolates varied in their growth temperature, NaCl tolerance, growth pH, enzyme activities, carbon utilization and antibiotic sensitivity tests. Fatty acid profiles indicate the predominance of branched fatty acids in the isolates. To the best of our knowledge, this is the first record of culturable bacterial communities and their characterization from glacier cryoconites from High Arctic. High amylase and protease activities expressed by Micrococcus sp. MLB-41 and amylase, protease and lipase activities expressed by Cryobacterium sp. MLB-32 provide a clue to the potential applications of these organisms. These cold-adapted enzymes may provide an opportunity for the prospect of biotechnology in Arctic.

Winogradskyella psychrotolerans sp. nov., a marine bacterium of the family Flavobacteriaceae isolated from Arctic sediment

A novel Gram-negative, rod–coccus shaped, non-motile, strain, RS-3T, was isolated from a sediment sample collected from the marine transect of Kongsfjorden, Ny-Ålesund, Svalbard, Arctic. Colonies and broth cultures were yellowish in colour due to the presence of carotenoids. Strain RS-3T was positive for oxidase, aesculinase, caseinase, gelatinase and urease activities and negative for amylase, catalase, lipase, lysine decarboxylase, ornithine decarboxylase, DNase and β-galactosidase activities. The predominant fatty acids were iso-C15 : 0 (18.0), anteiso-C15 : 0 (16.8), iso-C15 : 1 G (14.2), anteiso-C15 : 1 A (6.0) and iso-C15 : 0 3-OH (6.8). Strain RS-3T contained MK-6 (72.42 %) and MK-7 (27.58 %) as the major respiratory quinones and phosphatidylethanolamine, two unidentified aminolipids and two unidentified lipids make up the polar lipid composition. The DNA G+C content of strain RS-3T was 34.7±1.2 mol%. The 16S rRNA gene sequence analysis indicated that Winogradskyella pacifica and Winogradskyella thalassocola are the most closely related species with sequence similarities to the type strains of these species of 98.5 and 97.7 %, respectively. However, DNA–DNA hybridization with Winogradskyella pacifica KCTC 22997T and Winogradskyella thalassocola DSM 15363T showed a relatedness of 22 and 42.5 % with respect to strain RS-3T. Based on the DNA–DNA hybridization values, phenotypic and chemotaxonomic characteristics and phylogenetic inference, strain RS-3T is proposed as a novel species of the genus Winogradskyella , for which the name Winogradskyella psychrotolerans sp. nov. is proposed. The type strain of Winogradskyella psychrotolerans sp. nov. is RS-3T ( = CIP 110154T = NBRC 106169T). An emended description of the genus Winogradskyella is provided.

Carl woese: from biophysics to evolutionary microbiology

This article is a tribute to Carl R. Woese, a biophysicist turned evolutionary microbiologist who passed away on December 30, 2012. We focus on his life, achievements, the discovery of Archaea and contributions to the development of molecular phylogeny. Further, the authors share their views and the lessons learnt from Woese's life with the microbiologists in India. We also emphasize the need for interdisciplinary collaboration and interaction for the progress and betterment of science.

Diversity of chemotactic heterotrophic bacteria associated with arctic cyanobacteria

The abundance and diversity of chemotactic heterotrophic bacteria associated with Arctic cyanobacteria was determined. The viable numbers ranged between 10(4) and 10(6) cell g(-1) cyanobacterial biomass. A total of 112 morphotypes, representing 22 phylotypes based on their 16S rRNA sequence similarity were isolated from the samples. All the phylotypes were Gram-negative with affiliation to the proteobacterial and bacteroidetes divisions. Among the 22 phylotypes, 14 were chemotactic to glucose. Majority of the phylotypes were psychrotolerant showing growth up to 30 °C. Representatives of Alphaproteobacteria, the genus Flavobacterium and the gammaproteobacterial Alcanivorax sp, were psychrophilic with growth at or below 18 °C. A significant percentage of phylotypes were pigmented (~68 %), rich in unsaturated membrane fatty acids and tolerated pH values and NaCl concentrations between 5.0-8.0 and 0.15-1.0 M, respectively. The percentages of phylotypes producing extracellular cold-active enzymes at 4 °C were amylase (18.18 %), lipase and urease (45.45 %), caseinase (59.09 %) and gelatinase (31.8 %).

Lacinutrix himadriensis sp. nov., a psychrophilic bacterium isolated from a marine sediment, and emended description of the genus Lacinutrix

A novel gram-negative, rod-shaped, non-motile, psychrophilic bacterium, designated strain E4-9a(T), was isolated from a marine sediment sample collected at a depth of 276 m from Kongsfjorden, Svalbard, in the Arctic Ocean. The colony colour was golden yellow. Strain E4-9a(T) was positive for amylase activity at 5 °C. The predominant fatty acids were iso-C(15 : 1) G (21.8 %), anteiso-C(15 : 0) (19.1 %), anteiso-C(15 : 1) A (18.6 %), iso-C(15 : 0) (13.8 %) and iso-C(16 : 1) H (6.4 %). Strain E4-9a(T) contained MK-6 as the major respiratory quinone. The polar lipids consisted of phosphatidylethanolamine, three unidentified aminolipids (AL1, AL4 and AL5), an unidentified phospholipid and four unidentified lipids (L1, L4 to L6). Based on 16S rRNA gene sequence similarity, it was ascertained that the closest related species to E4-9a(T) were Lacinutrix copepodicola, L. algicola and L. mariniflava, with sequence similarity to the respective type strains of 98.5, 96.5 and 95.8 %. Phylogenetic analysis showed that strain E4-9a(T) clustered with the type strain of L. copepodicola and with those of L. algicola and L. mariniflava at distances of 1.5 and 4.8 % (98.5 and 95.2 % similarity), respectively. However, DNA-DNA hybridization with L. copepodicola DJ3(T) showed 59 % relatedness with respect to strain E4-9a(T). The DNA G+C content of strain E4-9a(T) was 29 mol%. Based on the results of DNA-DNA hybridization and phenotypic data, it appears that strain E4-9a(T) represents a novel species of the genus Lacinutrix, for which the name Lacinutrix himadriensis sp. nov. is proposed. The type strain is E4-9a(T) ( = CIP 110310(T)  = KCTC 23612(T)).

Oceanisphaera arctica sp. nov., isolated from Arctic marine sediment, and emended description of the genus Oceanisphaera

A novel Gram-staining-negative, coccoid, non-motile bacterium, designated strain V1-41(T), was isolated from a sample of marine sediment collected, at a depth of 200 m, from Kongsfjorden (an inlet on the west coast of Spitsbergen, an island that forms part of the Svalbard archipelago in the Arctic Ocean). The strain formed cream-brown colonies on marine agar. Cells of the novel strain were positive in tests for catalase, oxidase, lysine decarboxylase and ornithine decarboxylase activities but negative for gelatinase and lipase activities. They hydrolysed aesculin, starch and urea, but not casein or DNA. Most of the cellular fatty acids were medium-chain and saturated (37.1%) or long-chain and unsaturated (27.8%), with C(12:0) (37.1%), C(18:1)ω7c, and summed features 2 (19.3%) and 3 (24.1%) predominating. The major respiratory quinone was Q-8. The polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, two unidentified aminophospholipids, four unidentified phospholipids and one other unidentified lipid. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the novel strain's closest known relatives were Oceanisphaera litoralis DSM 15406(T) (98.5% sequence similarity) and Oceanisphaera donghaensis BL1(T) (98.3%). In DNA-DNA hybridizations, however, the levels of relatedness between strain V1-41(T) and O. litoralis DSM 15406(T) and between the novel strain and O. donghaensis DSM 17589(T) were found to be only 19% and 29%, respectively. Based on these low levels of similarity at the DNA-DNA level and the phenotypic and chemotaxonomic differences from O. litoralis DSM 15406(T) and O. donghaensis DSM 17589(T), strain V1-41(T) represents a novel species of the genus Oceanisphaera for which the name Oceanisphaera arctica sp. nov. is proposed. The type strain is V1-41(T) ( = CCUG 58690(T) = KCTC 23013(T) = NBRC 106171(T)).

Comparison of bacterial diversity in proglacial soil from Kafni Glacier, Himalayan Mountain ranges, India, with the bacterial diversity of other glaciers in the world

Two 16S rRNA gene clone libraries (KF and KS) were constructed using two soil samples (K7s and K8s) collected near Kafni Glacier, Himalayas. The two libraries yielded a total of 648 clones. Phyla Actinobacteria, Bacteroidetes, Chloroflexi Firmicutes, Proteobacteria, Spirochaetae, Tenericutes and Verrucomicrobia were common to the two libraries. Phyla Acidobacteria, Chlamydiae and Nitrospirae were present only in KF library, whereas Lentisphaerae and TM7 were detected only in KS. In the two libraries, clones belonging to phyla Bacteroidetes and Proteobacteria were the most predominant. Principal component analysis (PCA) revealed that KF and KS were different and arsenic content influenced the differences in the percentage of OTUs. PCA indicated that high water content in the K8s sample results in high total bacterial count. PCA also indicated that bacterial diversity of KF and KS was similar to soils from the Pindari Glacier, Himalayas; Samoylov Island, Siberia; Schrimacher Oasis, Antarctica and Siberian tundra. The eleven bacterial strains isolated from the above two soil samples were phylogenetically related to six different genera. All the isolates were psychro-, halo- and alkalitolerant. Amylase, lipase and urease activities were detected in the majority of the strains. Long chain, saturated, unsaturated and branched fatty acids were predominant in the psychrotolerant bacteria.

Bacterial diversity of soil in the vicinity of Pindari glacier, Himalayan mountain ranges, India, using culturable bacteria and soil 16S rRNA gene clones

Three 16S rRNA gene clone libraries (P1L, P4L and P8L) were constructed using three soil samples (P1S, P4S and P8S) collected near Pindari glacier, Himalayas. The three libraries yielded a total of 703 clones. Actinobacteria, Firmicutes and Proteobacteria were common to the three libraries. In addition to the above P1L and P8L shared the phyla Acidobacteria, Bacteroidetes, Gemmatimonadetes and Planctomycetes. Phyla Chlamydiae, Chlorobi, Chloroflexi, Dictyoglomi, Fibrobacteres, Nitrospirae, Verrucomicrobia, candidate division SPAM and candidate TM7s TM7a phylum were present only in P1L. Rarefaction analysis indicated that the bacterial diversity in P4S and P8S soil samples was representative of the sample. Principal component analysis (PCA) revealed that P1S and P8S were different from P4S soil sample. PCA also indicated that arsenic content, pH, Cr and altitude influence the observed differences in the percentage of specific OTUs in the three 16S rRNA gene clone libraries. The observed bacterial diversity was similar to that observed for other Himalayan and non-polar cold habitats. A total of 40 strains of bacteria were isolated from the above three soil samples and based on the morphology 20 bacterial strains were selected for further characterization. The 20 bacteria belonged to 12 different genera. All the isolates were psychro-, halo- and alkalitolerant. Amylase and urease activities were detected in majority of the strains but lipase and protease activities were not detected. Long chain, saturated, unsaturated and branched fatty acids were predominant in the psychrotolerant bacteria.