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Exopolymeric substances (EPS) produced by bacterial cells play a crucial role in the interaction of the cells with the surrounding environment. Halobacillus trueperi manxer mangrove-16, an adhered bacterial isolate from the mangrove ecosystem was found to produce EPS that was observed by Alcian blue staining and congo red-coomassie blue agar. The EPS of the bacterial isolate exhibited emulsifying properties. Purification of the EPS by dialysis showed an emulsification index of 80% with hexadecane. Qualitative analysis and Fourier's Infrared spectroscopy (FTIR) revealed that the EPS was a glycoprotein in nature. The EPS showed no surface-active properties. Further exploration of the potential of the EPS interaction with metal solutions showed the ability of the bioemulsifier to cause precipitation in the metal solutions and particularly change the color of the Chromium (VI) solution. The scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDS) of the cells and EPS particularly indicated the interaction of the EPS with the (Fe

High concentration of heavy metals in the environment triggers metal resistance mechanisms and act as a driving force in the proliferation of antibiotic resistance in microorganisms thereby raising ecological and health concerns. Hypersaline soils are naturally augmented with heavy metals. In current study, nine halophilic bacteria i.e. Halomonas elongata MB590, H. elongata MB591, H. elongata MB593, H. elongata MB594, H. elongata MB595, Halobacillus karajiensis MB588, Alkalibacillus almallahensis MB589, Aquisalibacillus elongatus MB592, and H. elongata MB596 were investigated for multiple heavy metal and antibiotic resistance patterns. These observations were further subjected to correlation as well as Principle Component Analysis (PCA) to identify the association between resistance of bacterial strains with respect to antibiotics and metals. All the isolates showed resistance to various antibiotics with Multiple Antibiotic Resistance (MAR) index above 0.2 for each strain. MAR and Multiple Heavy Metal Resistance (MHMR) indices revealed H. elongata MB593 as the most resistant strain to most of the heavy metals and antibiotics. Alkalibacillus almallahensis MB589 and A. elongatus MB592 were sensitive to all heavy metals and only isolate A. elongatus MB592 was found sensitive to most of the antibiotics. This MAR and MHMR in halophilic bacteria might be the consequence of a common mechanism they shared for antibiotic and heavy metal resistance. Correlation analysis between heavy metal and antibiotic resistance spectra of halophilic bacteria indicated strong association among heavy metal and antibiotic tolerance. This study provided a strong evidence for co-existence of heavy metal and antibiotic resistance in halophilic bacteria and gives insight for future study on the molecular basis of resistomes of these bacteria.

Understanding the salt tolerance of microbial communities may help to elucidate the effects of salt concentration and other environmental factors on soil biodiversity. Here, high-throughput sequencing of 16S rDNA and ITS was combined to investigate the distribution and salt tolerance of microbial communities in coastal soils and sediments near the Yinggehai saltern field of Hainan Island, China. The microbial communities in the soils and sediments of the land zone (YGHLS), the intertidal zone (YGHIS), and the inshore zone (YGHWS) were compared. PCoA of weighted and unweighted UniFrac distance revealed obvious differences in soil microbial community among different samples. ANOSIM analysis could clearly separate the three samples from each other. Three halotolerant bacteria, including Halomonas, Halobacillus and Wallemia, were found in the samples, which accounted for 0.0335 ± 0.0586%, 0.0241 ± 0.0304%, and 0.0308 ± 0.0445% of the total microbial community, respectively. The relative abundance of Trk system potassium uptake protein, Kdp operon response regulator, and Na+/H+ antiporter in the samples exceeded 0.09%, 0.06%, and 0.02%, respectively, indicating that the Trk system plays a major role in the salt tolerance of halotolerant bacteria in Yinggehai coastal soils and sediments.

In the current study, fourteen bacterial strains were obtained in salt contaminated soils. The identification and characterization of the bacterial strains were performed by conventional and molecular techniques. According to the results of 16S rRNA gene sequence analysis, five genera (Bacillus, Staphylococcus, Oceanobacillus, Exiguobacterium, and Halobacillus) were identified with a homology of equal to 99% or higher similarity. Afterward, these fourteen halotolerant/halophilic bacterial strains were investigated for their plant growth promoting (PGP) traits including production of indole-3-acetic acid (IAA) and siderophore, activity of 1-aminocyclopropane-1-carboxylate (ACC) deaminase, fixation of nitrogen, and phosphate solubilization potential. Five of the bacterial strains possessing PGP traits were tested for their effects on the growth of a salt sensitive plant (wheat) in a hydroponic system under salt stress (200 mM). Inoculation of five bacterial strains under salt stress significantly enhanced plant weight (Triticum aestivum) ranged from 71.18 to 89.04%. Salt stress amelioration potential of Oceanobacillus picturae and Staphylococcus succinus on T. aestivum has been shown for the first time in this study. In non-saline soil, the promising effect of plant growth bacteria is clear; however, in saline soil, the use of PGP halophilic and halotolerant bacteria can increase the productivity of salt sensitive plants. Therefore, the novel halophilic and halotolerant bacteria that promote plant growth can be developed for agricultural uses in saline soils., Agri Ibrahim Cecen University Scientific Researches Project [BAP-F.E.F.18.005], This study was supported by Agri Ibrahim Cecen University Scientific Researches Project (Project number: BAP-F.E.F.18.005).

The effects of halophilic bacteria (Halobacillus sp. and Marinobacter sp.) on pyrite and chalcopyrite surface oxidation in artificial seawater are studied by electrochemical impedance spectroscopy (EIS) in conjunction with X-ray diffraction (XRD) and cyclic voltammetry analysis (CV), in order to explain the influence of these microorganisms on the minerals floatability. EIS analyses on pyrite electrodes suggest that biomaterial from both bacteria adheres to the mineral surface, which is reinforced by CV experiments as capacitive currents are promoted by both bacteria. Additionally, XRD analyses of pyrite samples after immersion in artificial seawater with and without bacteria indicate the formation of hematite on the mineral surface in the presence of Halobacillus sp., which together with the adherence of biomaterial could promote the depression of pyrite during flotation. On the other hand, EIS and CV analyses on chalcopyrite electrodes suggest that the adherence of Halobacillus sp. and Marinobacter sp. to the surface of the mineral have no significant effects on the kinetics of the chalcopyrite oxidation processes. These results together with XRD analyses of the chalcopyrite samples after immersion in artificial seawater with and without bacteria suggest that superficial sulphur might have a stronger influence on chalcopyrite flotability than the presence of bacteria.

Background Salinity is typical in seashore soils due to the interruption of seawater in the groundwater. Soil microbes of coastal regions play a vital role in increasing plant yields. Microbe-plant associated growth and its wide spectrum with soil environment remain one of the prime factors in agriculture for field application. Making such, in this study, very precise research work is outlined to serve microbial-based solution for solubilizing the insoluble phosphate under various harsh environmental conditions and IAA production. Salt-affected soils along the coast of Bay of Bengal, Sundarbans, India, have been collected. Results A total of five isolates effectively solubilize the considerable amount of Tri-calcium phosphate {TCP, (Ca3PO4)2} ranging from 50.67 to 116.66 P2O5 parts per million (ppm) under optimized conditions, i.e., pH 8.0, 5 to 10% saline and 30 °C temperature. Out of five, three produced Indole Acetic Acid (IAA) ranging from 0.054 to 0.183 (g l−1). Identification of isolates has been carried out by morphology, biochemical characterization and 16S rDNA sequencing. Among the sequenced isolates, 1 belonged to Firmicutes, 3 were Proteobacteria and 1 was Actinobacteria. Conclusion This is the first report which shows the presence of phosphate solubilizing activity by the member of the genus Halomonas and Halobacillus from the study site. These stress-tolerant bacteria will deliver reliable and cost-effective methods to overcome the existing scenario of saline-affected agriculture.

Soda lakes characterized by salinity and elevated pH, these lakes represent a vast reservoir of novel microbial diversity of potential applications. In this article, two distinct salt lakes in northwestern Egypt were explored for the diversity of cultivable aerobic haloalkaliphilic bacteria. Physicochemical analyses revealed that samples possessed the characteristic features of alkaline hypersaline lakes (high pH, high Na+, and Cl− content with low Mg+2). The phenotypic characterization showed great diversification between members of the same genus. They were characterized phenotypically based on their cell and colony morphology, production of extra-cellular enzymes, some metabolic activities and antibiogram profile. Phylogenetic analysis was performed using 16S rRNA sequence. All strains were haloalkaliphilic belonging to phylum Firmicutes. They were affiliated to the genera Alkalibacillus, Salinicoccus, Gracilibacillus, Thalassobacillus, Halobacillus, Staphylococcus, and Bacillus. Surprisingly, Thalassobacillus species were only isolated from the sediment of Marsa-Matrouh lake (MML), while members of the genera Alkalibacillus, Salinicoccus and Staphylococcus were isolated from the sediment of Al-Hamra lake (AHL). Members of the genus Gracilibacillus were among the common community of the two lakes.

PURPOSE: In this study, the culturable halophilic and halotolerant bacterial diversity was determined in Aran-Bidgol as a thalassohaline seasonal hypersaline lake in Iran. METHODS: Thirty water, soil, sediments, coastal mud, multi-color brines and salt crystals samples were extracted and cultured using different media and incubation conditions. Totally 958 isolates were obtained and 87 isolates were selected for further studies, based on morphological, physiological and biochemical tests, representing different morphotypes. RESULTS: Based on 16S rRNA gene sequence analyses, the isolates exhibited 94.6–100% sequence similarity to the closest known species of the genera Bacillus, Halomonas, Oceanobacillus, Salinicoccus, Thalassobacillus, Ornithinibacillus, Halobacillus, Salicola, Virgibacillus, Aerococcus, Arthrobacter, Idiomarina, Paraliobacillus, Staphylococcus, Acinetobacter, Aneurinibacillus, Brevibacillus, Brevundimonas, Chromohalobacter, Gracilibacillus, Jeotgalicoccus, Kocuria, Marinilactibacillus, Marinobacter, Microbacterium, Paenibacillus, Paracoccus, Piscibacillus, Pseudomonas and Sediminibacillus and also, comparison of ARDRA patterns among the sequenced strains, using AluI, Bst UI and Hpa II enzymes showed that these patterns are in accordance with the phylogenetic position of these strains. CONCLUSION: The PCR-RFLP analyses suggested that ARDRA possess a functional potential for distinguishing halophilic bacteria to be used for further studies in elementary steps of isolation to reduce the tedious duplication of isolates.

This study investigated the inhibitory activity of

An aerobic, Gram-stain-positive, endospore-forming, rod-shaped and moderately halophilic strain SKP4-6T, was isolated from shrimp paste (Ka-pi) collected from Samut Sakhon Province, Thailand. Phylogenetic analysis revealed that strain SKP4-6T belonged to the genus Halobacillus and was most closely related to Halobacillus salinus JCM 11546T (98.6 %), Halobacillus locisalis KCTC 3788T (98.6 %) and Halobacillus yeomjeoni KCTC 3957T (98.6 %) based on 16S rRNA gene sequence similarity. The digital DNA–DNA hybridization (dDDH) and average nucleotide identity (ANI) values between strain SKP4-6T and its related species were 18.2–19.3 % and 69.84–84.51 %, respectively, which were lower than the threshold recommended for species delineation. The strain grew optimally at 30–40 °C, at pH 7.0 and with 10–15 % (w/v) NaCl. It contained l-Orn–d-Asp in the cell wall peptidoglycan. The DNA G+C content was 44.8 mol%. The major fatty acids were iso-C15 : 0, anteiso-C15 : 0 and anteiso-C17 : 0. The predominant isoprenoid quinone was MK-7. Phosphatidylglycerol and diphosphatidylglycerol were present as major polar lipids. Based on this polyphasic approach, digital DNA–DNA relatedness and ANI values, strain SKP4-6T represents a novel species of the genus Halobacillus , for which the name Halobacillus fulvus sp. nov. is proposed. The type strain is SKP4-6T (=JCM 32624T=TISTR 2595T).

Background: Bacteria are one of the important sources of producing enzymes. The aim of this study was to the isolate the halophilic bacteria producing amylase, lipase and pectinase from saline soil of the center of Iran. Methods: In this study, soil samples were collected from Dagh Biarjmand and Haj Aligholi in Semnan province. At first, isolated halophilic bacteria were cultured and screened for producing of hydrolytic enzymes including amylase, lipase and pectinase using enzyme-specific media. The enzymatic activities of isolates were recognized by induction of growth inhibition zone and/or precipitation around colonies after addition of related indicators. Afterward, enzyme positive isolates were identifies using the 16S rRNA sequencing. Results: Out of 7 bacterial isolates, 4 bacteria with amylase activity, 6 bacteria with lipase activity and 3 bacteria with pectinase activity were recognized and identified. Results showed that 2 isolates with the ability of producing all three types of enzymes belong to Bacillus genus using molecular identification methods. Furthermore, the halophilic bacteria producing amylase and pectinase were belonging to Bacillus and Halobacillus genera. Besides, bacteria producing lipase belonged to Bacillus and Virgibacillus genera. Conclusion: The Bacillus bacteria isolated from the soil can produce all three amylase, pectinase and lipase enzymes.

A halophilic bacterial strain, EG1HP4QL, was isolated from a salt sample from Lake Qarun, Fayoum Province, Egypt. Morphological, physiological, biochemical, and phylogenetic analyses indicated that the strain belonged to the genus Halobacillus. Strain EG1HP4QL produced an extracellular polysaccharide (EPS), with production peaking (5.9 g L−1) during growth on medium S-G containing 2% (w/v) sucrose at 35 °C (pH 8.0). The EPS had significant emulsifying activity (E24 %) against kerosene (65.7 ± 0.8%), o-xylene (64.0 ± 1%), and sunflower oil (44.7 ± 0.5%). The composition of the EPS included two polymers—a negatively charged and a neutral one (~ 3:1)—in which mannose and glucose were the main neutral monosaccharide constituents. Strain EG1HP4QL was able to utilize crude oil (35.3%) as the sole carbon source within 12 days. The minimum inhibitory concentrations of heavy metals [Zn(II), Cd(II), Pb(II), Ni(II), and Cu(II)] for strain EG1HP4QL were 1.0, 2.0, 2.0, 2.5, and 5 mM, respectively.

Commercial table salt is a condiment with food preservative properties by decreasing water activity and increasing osmotic pressure. Salt is also a source of halophilic bacteria and archaea. In the present research, the diversity of halotolerant and halophilic microorganisms was studied in six commercial table salts by culture-dependent and culture-independent techniques. Three table salts were obtained from marine origins: Atlantic Ocean, Mediterranean (Ibiza Island), and Odiel marshes (supermarket marine salt). Other salts supplemented with mineral and nutritional ingredients were also used: Himalayan pink, Hawaiian black, and one with dried vegetables known as Viking salt. The results of 16S rRNA gene sequencing reveal that the salts from marine origins display a similar archaeal taxonomy, but with significant variations among genera. Archaeal taxa Halorubrum, Halobacterium, Hallobellus, Natronomonas, Haloplanus, Halonotius, Halomarina, and Haloarcula were prevalent in those three marine salts. Furthermore, the most abundant archaeal genera present in all salts were Natronomonas, Halolamina, Halonotius, Halapricum, Halobacterium, Haloarcula, and uncultured Halobacterales. Sulfitobacter sp. was the most frequent bacteria, represented almost in all salts. Other genera such as Bacillus, Enterococcus, and Flavobacterium were the most frequent taxa in the Viking, Himalayan pink, and black salts, respectively. Interestingly, the genus Salinibacter was detected only in marine-originated salts. A collection of 76 halotolerant and halophilic bacterial and haloarchaeal species was set by culturing on different media with a broad range of salinity and nutrient composition. Comparing the results of 16S rRNA gene metataxonomic and culturomics revealed that culturable bacteria Acinetobacter, Aquibacillus, Bacillus, Brevundimonas, Fictibacillus, Gracilibacillus, Halobacillus, Micrococcus, Oceanobacillus, Salibacterium, Salinibacter, Terribacillus, Thalassobacillus, and also Archaea Haloarcula, Halobacterium, and Halorubrum were identified at least in one sample by both methods. Our results show that salts from marine origins are dominated by Archaea, whereas salts from other sources or salt supplemented with ingredients are dominated by bacteria., This research was financially supported by the Spanish Government on SETH Project (reference: RTI2018-095584-B-C41-42-43-44, co-financed by FEDER funds and Ministerio de Ciencia, Innovación y Universidades), the Helios project (reference: BIO2015-66960-C3-1-R), and the European CSA on biological standardization BIOROBOOST (EU grant no. 820699). LS was funded by the European project BIOROBOOST. AL-P was funded by Doctorado Industrial fellowship from the Ministerio de Ciencia, Innovación y Universidades (reference: DI-17-09613).

Strain Marseille-Q1234T is a new species from the genus Halobacillus that was isolated in 2019 from stool sample in a healthy Malian child under five years old. Cells are gram-positive and strictly halophilic bacilli. Strain Marseille-Q1234T exhibits 98.46% 16S rRNA gene sequence similarity to Halobacillus naozhouensis strain JSM 071068 T (NR_116505.1), the phylogenetically closely related species with standing in nomenclature. Based on the phenotypic and phylogenetic evidence, OrthoANI values and results of the biochemical tests, a new species named Halobacillus ihumii sp. nov., for which strain Marseille-Q1234T (= CSURQ1234) is proposed as the type strain.

Purpose In this work, we assessed the diversity of culturable halophilic bacteria that produce hydrolytic enzymes from both natural and artificial hypersaline regions in the pre-Rif region of Morocco. Methods Bacteria were isolated from three hypersaline sites, in solid medium supplemented with various salt concentrations ranging from 0 to 330 g/L. Physical and chemical characteristics of samples from the isolation site were determined to suggest eventual correlations with the occurrence of the halophilic bacteria. Assays on enzymatic activities were performed in submerged cultures in the presence of various salt concentrations and appropriate substrates. Results Out of a collection of 227 halophilic bacteria, four halophilic groups were established as slightly halophilic, moderately halophilic, halotolerant, or extremely halophilic, with a predominance of halophilic bacteria in the natural hypersaline sites compared to the artificial one. Within this collection, 189 strains showed important hydrolytic activities in submerged cultures with enzymatic activities up to 76 U/mg. Strain characterization and identification was based on phenotypic and molecular traits and allowed the identification of at least 26 genera including Bacillus, Chthonibacter, Mariniabilia, Halobacillus, Salinococcus, Cerasicoccus, Ulvibacter, Halorubrum, Jeatgalicoccus, Brevibacterium, Sanguibacter, Shewanella, Exiguobacterium, Gemella, and Planomicrobium. Conclusion Data from this study give insights about the origin and the occurrence of halophilic bacteria in natural hypersaline environments compared to artificial hypersaline sites. The occurrence of halophilic hydrolase enzymes from halophilic bacteria gives insights to different applications in biotechnology, thanks to their ability to produce adaptive enzymes and survival strategies to overcome harsh conditions.

Introduction In recent years, a challenge in clinical treatment has developed due to bacterial resistance to antibiotics. One of the new mechanisms against infections is virulence factor inhibition. Many virulence factors are controlled by quorum sensing pathways such as biofilm formation and pyocyanin production. The goal of the present study was to investigate the effect of an obligate halophilic bacterial strain on Pseudomonas aeruginosa and Staphylococcus aureus, due to its halo-tolerant substances and enzymes. Methods The effect of Halobacillus karajensis on bacterial growth and production of virulence factors was studied in this work. The obligate halophile cells and supernatant fractions were extracted by the methanol/chloroform method and characterized by Fourier Transform Infrared (FTIR) spectroscopy, X-ray diffraction (XRD), Gas Chromatography–Mass Spectrometry (GC-MS), and zymography. The effects of these fractions were studied on biofilm formation in P. aeruginosa and S. aureus as well as on pyocyanin production in P. aeruginosa. The effective protein in the fraction was analyzed by the SDS-PAGE method, and all protein fragments were studied for pyocyanin inhibition. Results The crude supernatant extract, MMS fraction, from H. karajensis was effective for the biofilm reduction in S. aureus (74%) and P. aeruginosa (27%). Two proteases in this fraction, which were recognized by zymography on skim milk, were the probable causes for extracellular polymeric substances (EPS) hydrolysis in the biofilm matrix. Also, halide crystals and branched fatty acids, 12methyl-tetradecanoic acid, in the other fractions decreased the biofilm by 18% in S. aureus. The results showed that a new 25 kD protein, which was obtained from MMS fraction, inhibited pyocyanin production by 60% in P. aeruginosa. The zymogram and bioinformatics studies showed that this protein was a serine alkaline metalloprotease and had an interaction with AHL molecules. Conclusion The inhibitory effects of the non-toxic natural substances and proteases on biofilm formation and pyocyanin production, specifically the 25 kD protease, are novel in this study and make them a good candidate for infected wound healing and inhibiting the virulence factors.

In the emerging scenario of increasing antibiotic resistance and pathogen transmission channels, the grave danger posed by bacterial endospores in critical fields like food industry, health and medicine highlights the urgent need to develop efficient probes for their detection; their sturdy and impermeable multilayer coat makes desirable methods like fluorescence imaging extremely difficult. Selective imaging of the endospores in the presence of the bacteria is even more challenging. Furthermore, it is preferable to maintain the dormant state of endospores through the imaging process, if extended monitoring is required; many of the available techniques involve lethal germination or destruction of the endospores. We show that simple zwitterionic diaminodicyanoquinodimethane (DADQ) molecules with selected functionalities are efficient dyes for fluorescence imaging due to their dipolar structure that facilitates the penetration into the endospore system, and the enhanced fluorescence in their rigid/aggregated state. The facile structural tailorability allows DADQs with various appendage moieties to be synthesized; a derivative with ionic substituents (BT2), and another with optimally long alkyl chains and the resultant hydrophobic character (BHADQ) are shown to be excellent fluorescent probes for endospores. Nanomolar amounts of dyes provide effective staining; while BT2 stains bacteria and endospores, most significantly, BHADQ stains endospores selectively. To the best of our knowledge, this is the first example of selective fluorescence imaging of endospores in their dormant state. A range of spectroscopy, microscopy and calorimetry studies provide insight into the molecular level interactions that enable efficient staining and bright images. DADQ fluorophores are photostable and non-cytotoxic, hence useful in practical applications. The versatile structural tailorability of these dye molecules holds great promise for targeted imaging.

Microbes from hypersaline environments are useful in biotechnology as sources of novel enzymes and proteins. The current study aimed to characterize halophilic bacteria from the rhizosphere of halophytes (Salsola stocksii and Atriplex amnicola), non-rhizospheric, and brine lake-bank soils collected from Khewra Salt Mine and screening of these bacterial strains for industrially important enzymes. A total of 45 bacterial isolates from the rhizosphere of Salsola, 38 isolates from Atriplex, 24 isolates from non-rhizospheric, and 25 isolates from lake-bank soils were identified by using 16S rRNA gene analysis. Phylogenetic analysis showed that bacterial strains belonging to Bacillus, Halobacillus, and Kocuria were dominant in the rhizosphere of halophytes (Salsola and Atriplex), and Halobacillus and Halomonas were dominating genera from non-rhizospheric and lake-bank soils. Mostly identified strains were moderately halophilic bacteria with optimum growth at 1.5–3.0 M salt concentrations. Most of the bacterial exhibited lipase, protease, cellulase, amylase, gelatinase, and catalase activities. Halophilic and halotolerant Bacilli (AT2RP4, HL1RS13, NRS4HaP9, and LK3HaP7) identified in this study showed optimum lipase, protease, cellulase, and amylase activities at 1.0–1.5 M NaCl concentration, pH 7–8, and temperature 37 °C. These results indicated that halophilic and halotolerant bacteria can be used for bioconversion of organic compounds to useful products under extreme conditions. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s42770-019-00044-y) contains supplementary material, which is available to authorized users.

At the limits of life, hyper-saline aquatic ecosystems; Chott and Sebkha are a model of choice of extreme environments, housing a halophilic microflora that had to adapt to these conditions. In Algeria, these ecosystems are poorly studied. However, our study was carried out on the waters of Chott Tinsilt and Sebkha El Malah. The study of this microflora revealed the presence of a significant morphological, physiological and metabolic diversity. The molecular study allowed us to access to a phylogenetic affiliation including an Archean Species (ATS1) and 7 bacterial species (A1, A2, A3, A4, B1, B4, B5). The results showed that these isolates were related to the genera Haloferax (for the strain ATS1) and Halomonas (strains A1, A2 and A4), Staphylococcus (strain A3), Salinivibrio (strain B1), Planococcus (strain B4) and Halobacillus (strain B5). Most isolates produced hydrolases at high salt concentrations. The Production yields obtained are very promising for applications in the biotechnology and industrial microbiology.

Bin-Salman SA, Amasha RH, Jastaniah SD, Aly MM, Altaif K. 2018. Isolation, molecular characterization and extracellular enzymatic activity of culturable halophilic bacteria from hypersaline natural habitats. Biodiversitas 19: 1828-1834. Saline habitats, like the Dead Sea, are unusual extreme environments, due to their extreme salinity. Most saline habitats originate from the evaporation of seawater, and have a nearly neutral to slightly alkaline pH (such as the Red Sea (pH8.3) and Arabian Gulf, pH8.3). Ten halophilic bacterial strains (two Gram-negative) belonging to the family of Halomonadaceae and (eight Gram-positive), belonging to the family of Bacillaceae, were isolated from the Red Sea, Arabian Gulf, and Dead Sea by subjecting the isolates to a high salinity medium, followed by identification using 16S rRNA gene sequencing. Four of isolates were designated on the basis of their tolerance to high salinity; SBR1 exhibited 97% homology to Halomonas aquamarina, SBR2 showed 97% homology to Sediminibacillus sp., (Red Sea), SBA9 exhibited 94% homology to Halobacillus sp., (Arabian Gulf) and SBD17 gave 98% homology to Halobacillus dabanensis (Dead Sea). The isolates were also characterized by their physiological parameters, SBR1 showed optimum growth at 30°C, pH8.5 and1.5M NaCl, SBR2 at 30°C, pH6.0 and 1M NaCl. Optimum conditions for SBA9 were 35°C, pH6.5 and 1M NaCl and for SBD17, 37°C, pH7.0 and 1M NaCl.

Salinity is one of the major abiotic stresses; a total of 3% of the world’s land mass is affected by salinity. Approximately 6.3 million hectares of land in Pakistan is affected by salinity to varying degrees, and most of the areas are arid to semiarid with low annual precipitation. The aim of the present study is to identify and characterize Bacillus and Bacillus-derived bacterial genera from the rhizospheric and non-rhizospheric soil samples from the Khewra Salt Mine, Pakistan, by using culture-independent and -dependent methods. Seven Bacillus-like bacterial genera, Bacillus, Halobacillus, Virgibacillus, Brevibacillus, Paenibacillus, Tumebacillus, and Lysinibacillus, were detected by using pyrosequencing analysis, whereas only four genera, Bacillus, Halobacillus, Oceanobacillus, and Virgibacillus, were identified by culture-dependent methods. Most of the Bacillus-like isolates identified in this study were moderately halophilic, alkaliphilic, and mesophilic bacteria and were considered a good source of hydrolytic enzymes because of their ability to degrade proteins, carbohydrates, and lipids. Eight Bacillus-like strains from the genera Bacillus, Halobacillus, Oceanobacillus, and Virgibacillus showed positive results for the presence of ectABC gene cluster (ectoine), six strains could synthesize betaine from choline, and six strains tested positive for the synthesis of proline from either glutamate or ornithine by using proline dehydrogenase enzyme.

Increase in soil salinity adversely affects the metabolism and lowers the yield of rice (Oryza sativa L). Application of plant growth-promoting rhizobacteria (PGPR) to ameliorate the effects of salt stress on sensitive rice can be both effective and sustainable. In this study, 20 bacterial strains were isolated from the soil of saline-prone regions of Satkhira, north of the Sundarbans in coastal Bangladesh. Three bacteria among these grew well in the presence of 3 M salt (NaCl) and were Gram positive and non-motile. Their 16S rRNA sequence revealed that they belong to the Halobacillus genus. Two of them were identified as Halobacillus dabanensis strain SB-26 and the other one as Halobacillus sp. GSP 34. A couple of mechanisms by which these microbes could play beneficial role if associated with plants, such as nitrogen fixation and indole acetic acid (IAA) production, were identified. The two bacterial strains showed positive results for nitrogen fixation and indole acetic acid (IAA) activity under salt stress. Their effect on the physiology and yield of a farmer popular but sensitive BRRI dhan 28 rice variety was investigated under both control and salt stress. At the seedling stage, inoculated plants had significantly greater root length, shoot height, total weight, chlorophyll content, but lower electrolyte leakage both in control and salt stress (0, 40, and 80 mM). Performance of the plants was even better when both bacteria were used in combination. At the reproductive stage, the plants also showed better phenology in presence of the inoculated bacteria. Under stress (50 mM NaCl), these plants showed significantly greater plant height, lower spikelet damage, and yield reduction compared to untreated plants. The identified Halobacillus strains can therefore be used to improve the yield of rice by exploiting their plant growth promotion activities in coastal areas affected by moderate salinity, such as those with an ionic conductivity of up to 5 dS m−1.

The bacterial community composition in the A horizon of a natural saline-alkaline soil located in Ararat Plain (Armenia) was studied using molecular and culture-based methods The sequence analysis of a 16S rRNA gene clone library and denaturing gradient gel electrophoresis (DGGE) profiles indicated dominance of Firmicutes populations. The majority of the sequences of the bacterial 16S rRNA gene library were close relatives of representatives belonging to the genera Halobacillus (41.2%), Piscibacillus (23.5%), Bacillus (23.5%) and Virgibacillus (11.8%). Eight novel moderately halophilic bacilli isolates were successfully obtained from the enriched cultures of the saline-alkaline soil samples. 16S rRNA gene sequence analyses of isolates revealed their affiliation (97.7-99.7% similarity) to representatives of the genera Bacillus, Piscibacillus and Halobacillus. All isolates were able to tolerate high concentrations of NaCl and highly alkaline conditions. This is the first study combining cultivation-independent and -dependent approaches to reveal the bacterial diversity of the saline-alkaline soils of Ararat Plain and it suggested an important role of bacilli as key microbes in biogeochemical cycles of these environments.

Members of the Bacillaceae family, including Bacillus spp., Brevibacillus spp., Paenibacillus spp., Aneurinibacillus sp., and Halobacillus sp., are an important source of structurally diverse classes of short peptides of ∼ 30 residues or fewer possessing peculiar and rapid killing activity against various pathogens. Additionally, many have unique structures that enhance resistance to hydrolysis by proteases, and these are ideal therapeutic tools and potential alternatives to current antibiotics. The need for novel antibiotic lead compounds is urgent, and this review summarises 119 Bacillaceae compounds published since 2000, including 12 surfactin-like lipopeptides, 16 iturinic lipopeptides, fengycin C, 33 other cyclic lipopeptides, 26 linear lipopeptides, two thiopeptides, four 2,5-diketopiperazines, 20 typical cyclic peptides, and five standard linear peptides. The current and potential therapeutic applications of these peptides, including structure, antibacterial, antifungal, and antiviral activities, are discussed.

Due to the presence of efflorescences and improper microclimate conditions for conservation, pink-pigmented areas were reported in two historic monuments in Northern and Central part of Romania. The aims of the present study were to find the nature of pink pigments observed on the pictorial layer, original and infilling mortar, to investigate the presence of carotenoids both on mural paintings and in the isolated halophilic bacterial strains and to preliminary characterize and identify the producing strains. Their role in the aesthetical biodeterioration of historic monuments was also pointed out. Obtained Raman spectra of the pink pigments extracted both from the isolated bacterial cultures (molecularly identified as mostly related to Halobacillus hunanensis and Halobacillus naozhouensis) and from the mural painting samples contain diagnostic bands of carotenoids. These results were confirmed by FTIR spectroscopy. The strong Raman signal of bacterial carotenoids detected on mural painting indicated their potential use as biomarker molecules in the evaluation of contamination and state of conservation of mural paintings and lithic monuments. Our results contribute to opening a new direction in cultural heritage restoration to assess the conservation status on the basis of interdisciplinary research, starting with spectroscopic methods (Raman, FTIR) and confirmed by microbiological analysis.

Algicidal behavior is a common interaction between marine microalgae and bacteria, especially in the dissipation phase of algal blooms. The marine bacterium Halobacillus sp. P1 was previously isolated and exhibits high algicidal activity against the diatom Skeletonema costatum. However, little is known about the mechanism underlying this algicidal process. Here, a tandem mass tag (TMT)-based proteomic approach was coupled with physiological analysis to investigate the cellular responses of S. costatum when treated with P1 culture supernatant. Among the 4582 proteins identified, 82 and 437 proteins were differentially expressed after treatment for 12 and 24 h, respectively. The proteomic results were in accordance with the results of verification by parallel reaction monitoring (PRM) assays. Proteins involved in reactive oxygen species scavenging, protein degradation and transport were upregulated, while proteins participating in nitrogen metabolism, protein translation, photosynthetic pigment biosynthesis and cell cycle regulation were significantly downregulated (p-value ≤0.05), corresponding to the increasing malondialdehyde content and the decreasing nitrogen, protein and chlorophyll a contents. A nutrient competitive relationship might exist between the bacterium P1 and S. costatum, and the inhibition of nitrogen metabolism by the P1 culture supernatant might be the key lethal factor that results in the dysfunction of S. costatum metabolism. Our study sheds light on the algicidal mechanism of P1 at the molecular level and provides new insights into algae-bacteria interactions.

The Sambhar Salt Lake is a halite rich athalassohaline basin, provides a unique opportunity for microbial ecologists to study halophiles. The lake has a high proportion of Na+ and Cl− ions making it a hypersaline ecosystem. In the current study, archaea and bacteria from Sambhar Lake were isolated using two cultivation approaches. A total of 449 isolates were obtained, out of which 13 represent archaeal while 12 represent bacterial genera. Natronococcus and Alkalibacillus were found predominant groups among archaea and bacteria, respectively. Apart from the common genera in both the approaches Alteribacillus, Halobacillus, Halorubrum, Lentibacillus, Natronorubrum, Piscibacillus and Thalassobacillus were found only in the samples processed onsite however only three genera Aliidiomarina, Natrinema and Natronolimnobius were isolated when samples were processed in the laboratory after transportation using the same growth conditions. Other than the isolation of diverse group of organisms 13 putative novel taxa with similarity less than 98% were identified using 16S rRNA gene sequencing.

This paper aims to characterize halophilic bacteria inhabiting Algerian Saline Ecosystems (Sebkha and Chott) located in arid and semi-arid ecoclimate zones (Northeastern Algeria). In addition, screening of enzymatic activities, heavy metal tolerance and antagonistic potential against phytopathogenic fungi were tested. A total of 74 bacterial isolates were screened and phylogenetically characterized using 16S rRNA gene sequencing. The results showed a heterogeneous group of microorganisms falling within two major phyla, 52 strains belonging to Firmicutes (70.2%) and 22 strains (30.8%) of γ-Proteobacteria. In terms of main genera present, the isolates were belonging to Bacillus, Halobacillus, Lentibacillus, Oceanobacillus, Paraliobacillus, Planomicrobium, Salicola, Terribacillus, Thalassobacillus, Salibacterium, Salinicoccus, Virgibacillus, Halomonas, Halovibrio, and Idiomarina. Most of the enzymes producers were related to Bacillus, Halobacillus, and Virgibacillus genera and mainly active at 10% of growing salt concentrations. Furthermore, amylase, esterase, gelatinase, and nuclease activities ranked in the first place within the common hydrolytic enzymes. Overall, the isolates showed high minimal inhibitory concentration values (MIC) for Ni2+ and Cu2+ (0.625 to 5 mM) compared to Cd2+ (0.1 to 2 mM) and Zn2+ (0.156 to 2 mM). Moreover, ten isolated strains belonging to Bacillus, Virgibacillus and Halomonas genera, displayed high activity against the pathogenic fungi (Botrytis cinerea, Fusarium oxyporum, F. verticillioides and Phytophthora capsici). This study on halophilic bacteria of unexplored saline niches provides potential sources of biocatalysts and novel bioactive metabolites as well as promising candidates of biocontrol agents and eco-friendly tools for heavy metal bioremediation.

Here we report the biological synthesis of CdS fluorescent nanoparticles (Quantum Dots, QDs) by polyextremophile halophilic bacteria isolated from Atacama Salt Flat (Chile), Uyuni Salt Flat (Bolivia) and the Dead Sea (Israel). In particular, a Halobacillus sp. DS2, a strain presenting high resistance to NaCl (3–22%), acidic pH (1–4) and cadmium (CdCl2 MIC: 1,375 mM) was used for QDs biosynthesis studies. Halobacillus sp. synthesize CdS QDs in presence of high NaCl concentrations in a process related with their capacity to generate S2− in these conditions. Biosynthesized QDs were purified, characterized and their stability at different NaCl concentrations determined. Hexagonal nanoparticles with highly defined structures (hexagonal phase), monodisperse size distribution (2–5 nm) and composed by CdS, NaCl and cysteine were determined by TEM, EDX, HRXPS and FTIR. In addition, QDs biosynthesized by Halobacillus sp. DS2 displayed increased tolerance to NaCl when compared to QDs produced chemically or biosynthesized by non-halophilic bacteria. This is the first report of biological synthesis of salt-stable QDs and confirms the potential of using extremophile microorganisms to produce novel nanoparticles. Obtained results constitute a new alternative to improve QDs properties, and as consequence, to increase their industrial and biomedical applications.

The aim of the present study was to obtain insights into the relationship between the chemical (salt content and pH) and physico-mechanical (humidity and compressive strength) properties of mineral-based materials from historic buildings with salt efflorescence and the growth and biodiversity of halophilic microorganisms. Samples were mainly characterized by pH 6.5–8.5 and a moisture content of between 0.12 and 3.3%. Significant variations were also found in the salt content (sulfates, chlorides, and nitrates) of the materials. An SEM/EDS analysis of material surfaces revealed the presence of halite, calcite, gypsum, sodium sulfate, and potassium-sodium sulfate. Culture-dependent and culture-independent (clone library construction) approaches were both applied to detect halophilic microorganisms. Results derived from culturable methods and the materials analysis revealed a correlation between the total halophile count and pH value as well as sulfate content. A correlation was not observed between the concentration of chlorides or nitrates and the number of halophilic microorganisms. The materials studied were inhabited by the culturable halophilic bacteria Halobacillus sp., Virgibacillus sp., and Marinococcus sp. as well as the yeast Sterigmatomyces sp., which was isolated for the first time from mineral materials. Culture-independent techniques revealed the following bacterial species: Salinibacterium, Salinisphaera, Rubrobacter, Rubricoccus, Halomonas, Halorhodospira, Solirubrobacter, Salinicoccus, and Salinibacter. Biodiversity was the highest in materials with high or moderate salinity.

The draft genome sequence of the halophilic bacterium Halobacillus mangrovi KTB 131, isolated from Topan salt of the Jeon-nam in Korea, was established. The genome comprises 4,151,649 bp, with a G + C content of 41.6%. The strain displays a high number of genes responsible for secondary metabolite biosynthesis, transport, and catabolism compared to other Halobacillus bacterial genus members. Numerous genes responsible for various transport systems, solute accumulation, and aromatic/sulfur decomposition were detected. The first genomic analysis encourages further research on comparative genomics and potential biotechnological applications. The whole draft genome sequence of Halobacillus mangrovi KTB 131 is now available (Bioproject PRJNA380285).

In the present study, an attempt has been made to explore the antifouling potential of bioactive compound isolated from sponge associated bacterium Halobacillus kuroshimensis SNSAB01. The crude extract of SNSAB01 strongly inhibited the growth of fouling bacterial strains with least minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The bioactive compound was characterized through FT-IR, HPLC, GC MS and NMR predicted as ‘pyrrolo”. From the mass spectral library, structure was elucidated as pyrrolo [1, 2-a] pyrazine-1, 4-dione, hexahydro. The in silico studies provided encouraging docking scores with two interactions by GLN 200 and GLU 304. The extract inhibited 89% diatom adhesion at 350 μg/ml concentration against Amphora sp. An EC50 value of 150 μg/ml for 50% inhibition of byssal thread of Perna viridis and LC50 was found to be 500 μg/ml. The LC50/EC50 ratio of 3.0 indicated nontoxic to nature. The result suggested that pyrrolo[1,2-a]pyrazine-1,4-dione can be used for antifouling coating.

Understanding the effect of conventional and alternative fuels on the marine bacterial community is crucial, as it pertains to the impact, biodegradation, and final fate of these fuels in the environment. Metagenomics analysis demonstrated that conventional and alternative fuels promoted the growth of Proteobacteria. Marinobacter and Desulfovibrio were predominant in seawater exposed to conventional jet propellant-5 (JP-5), while Hyphomonas and Rhodovulum were most abundant in seawater with hydroprocessed renewable jet fuel (HRJ) and conventional F-76 diesel, respectively. The phyla Bacteroidetes, Firmicutes, and Lentisphaerae were underrepresented in samples with fuel, and these phyla were largely comprised of unclassified bacteria. Culture-dependent tests isolated several of the same genera detected in high abundance by metagenomics DNA sequencing, including Marinobacter, Rhodovulum, and Halobacillus. Growth studies in fuel and gas chromatography analysis demonstrated that isolates grew in fuel and meta...

A Gram-staining-positive, moderately halophilic bacterium, designated strain NGS-2T, was isolated from sediment of a solar saltern pond located in Shinan, Korea. Strain NGS-2T was a strictly aerobic, non-motile rod that grew at pH 5.0–10.0 (optimum, pH 8.0), at 10–30 °C (optimum, 28 °C) and in the presence of 1–20 % (w/v) NaCl (optimum, 10 % NaCl). Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain NGS-2T belonged to the genus Halobacillus, with sequence similarity of 98.4–95.8 % to existing type strains, showing the highest sequence similarity to Halobacillus dabanensis D-8T (98.4 %), H. litoralis SL-4T (98.4 %), H. trueperi SL-5T (98.2 %), H. faecis IGA7-4T (98.2 %), H. profundi IS-Hb4T (98.1 %) and H. mangrovi MS10T (98.0 %). The major polar lipids were phosphatidylglycerol, phosphatidylethanolamine, phosphatidyl-N-methylethanolamine and an unknown glycolipid. The cell-wall peptidoglycan was based on l-Orn–d-Asp, the predominant isoprenoid quinone was menaquinone 7 (MK-7) and the major fatty acids were anteiso-C15: 0 and anteiso-C17: 0. The DNA G+C content of the novel isolate was 45.0 mol%. Levels of DNA–DNA relatedness between strain NGS-2T and the type strains of 12 other species of the genus ranged from 32 to 3 %. On the basis of the polyphasic analysis conducted in this study, strain NGS-2T represents a novel species of the genus Halobacillus, for which the name Halobacillus sediminis sp. nov. is proposed. The type strain is NGS-2T ( = KACC 18263T = NBRC 110639T).