Moderate Halophilic Bacteria Research Articles

Isolation and molecular identification of moderate halophilic enzyme-producing bacteria

Isolation and molecular identification of moderate halophilic enzyme-producing bacteria

Determination of Minimum Inhibitory Concentrations of Sophorolipids Against Selected Halotolerant and Moderately Halophilic Bacteria, and Extremely Halophilic Archaea Isolated from Salt Samples and Salted Skins

Determination of Minimum Inhibitory Concentrations of Sophorolipids Against Selected Halotolerant and Moderately Halophilic Bacteria, and Extremely Halophilic Archaea Isolated from Salt Samples and Salted Skins

Characteristics, Performance and Microbial Response of Aerobic Granular Sludge for Treating Tetracycline Hypersaline Pharmaceutical Wastewater.

Salt-tolerant aerobic granular sludge(AGS) was successfully cultivated under the dual stress of tetracycline and 2.5% salinity, resulting in an average particle size of 435.0 ± 0.5 and exhibiting a chemical oxygen demand(COD) removal rate exceeding 80%, as well as excellent sedimentation performance. The analysis of metagenomics technology revealed a significant pattern of succession in the development of AGS. The proportion of Oleiagrimonas, a type of salt-tolerant bacteria, exhibited a gradual increase and reached 38.07% after 42 days, which indicated that an AGS system based on moderate halophilic bacteria was successfully constructed. The expression levels of targeted genes were found to be reduced across the entire AGS process and formation, as evidenced by qPCR analysis. The presence of int1 (7.67 log10 gene copies g-1 in 0 d sludge sample) enabled microbes to horizontally transfer ARGs genes along the AGS formation under the double pressure of TC and 2.5% salinity. These findings will enhance our understanding of ARG profiles and the development in AGS under tetracycline pressure, providing a foundation for guiding the use of AGS to treat hypersaline pharmaceutical wastewater.

Genome of Lamprobacter modestohalophilus ShNLb02, a moderate halophilic photosynthetic purple bacterium of the Chromatiaceae family.

The genome sequence of the moderately halophilic Lamprobacter modestohalophilus ShNLb02 was compared to those of other Lamprobacter and Halochromatium species. It revealed an average nucleotide identity of 94% to Lpb. modestohalophilus DSM 25653 and of 89.7% to Halochromatium roseum DSM 18859, underscoring their close phylogenetic relationship.

Tandem mass tag-based quantitative proteomics reveals osmotic adaptation mechanisms in Alkalicoccus halolimnae BZ-SZ-XJ29T , a halophilic bacterium with a broad salinity range for optimal growth.

The moderate halophilic bacterium Alkalicoccus halolimnae BZ-SZ-XJ29T exhibits optimum growth over a wide range of NaCl concentrations (8.3-12.3%, w/v; 1.42-2.1 mol L-1 ). However, its adaptive mechanisms to cope with high salt-induced osmotic stress remain unclear. Using TMT-based quantitative proteomics, the cellular proteome was assessed under low (4% NaCl, 0.68 mol L-1 NaCl, control (CK) group), moderate (8% NaCl, 1.37 mol L-1 NaCl), high (12% NaCl, 2.05 mol L-1 NaCl), and extremely high (16% NaCl, 2.74 mol L-1 NaCl) salinity conditions. Digital droplet PCR confirmed the transcription of candidate genes related to salinity. A. halolimnae utilized distinct adaptation strategies to cope with different salinity conditions. Mechanisms such as accumulating different amounts and types of compatible solutes (i.e., ectoine, glycine betaine, glutamate, and glutamine) and the uptake of glycine betaine and glutamate were employed to cope with osmotic stress. Ectoine synthesis and accumulation were critical to the salt adaptation of A. halolimnae. The expression of EctA, EctB, and EctC, as well as the intracellular accumulation of ectoine, significantly and consistently increased with increasing salinity. Glycine betaine and glutamate concentrations remained constant under the four NaCl concentrations. The total content of glutamine and glutamate maintained a dynamic balance and, when exposed to different salinities, may play a role in low salinity-induced osmoadaptation. Moreover, cellular metabolism was severely affected at high salt concentrations, but the synthesis of amino acids, carbohydrate metabolism, and membrane transport related to haloadptation was preserved to maintain cytoplasmic concentration at high salinity. These findings provide insights into the osmoadaptation mechanisms of moderate halophiles and can serve as a theoretical underpinning for industrial production and application of compatible solutes.

Molecular Characterization and Biocompatibility of Exopolysaccharide Produced by Moderately Halophilic Bacterium Virgibacillus dokdonensis from the Saltern of Kumta Coast.

The use of natural polysaccharides as biomaterials is gaining importance in tissue engineering due to their inherent biocompatibility. In this direction, the present study aims to explore the structure and biocompatibility of the EPS produced by Virgibacillus dokdonensis VITP14. This marine bacterium produces 17.3 g/L of EPS at 96 h of fermentation. The EPS was purified using ion exchange and gel permeation chromatographic methods. The porous web-like structure and elemental composition (C, O, Na, Mg, P, S) of the EPS were inferred from SEM and EDX analysis. AFM analysis revealed spike-like lumps with a surface roughness of 84.85 nm. The zeta potential value of −10 mV indicates the anionic nature of the EPS. Initial molecular characterization showed that the EPS is a heteropolysaccharide composed of glucose (25.8%), ribose (18.6%), fructose (31.5%), and xylose (24%), which are the monosaccharide units in the HPLC analysis. The FTIR spectrum indicates the presence of functional groups/bonds typical of EPSs (O-H, C-H, C-O-H, C-O, S=O, and P=O). The polymer has an average molecular weight of 555 kDa. Further, NMR analysis revealed the monomer composition, the existence of two α- and six β-glycosidic linkages, and the branched repeating unit as → 1)[α-D-Xylp-(1 → 2)-α-D-Glcp-(1 → 6)-β-D-Glcp-(1 → 5)]-β-D-Frup-(2 → 2)[β-D-Xylp-(1 → 4)]-β-D-Xylp-(1 → 6)-β-D-Fruf-(2 → 4)-β-D-Ribp-(1 →. The EPS is thermally stable till 251.4 °C. X-ray diffraction analysis confirmed the semicrystalline (54.2%) nature of the EPS. Further, the EPS exhibits significant water solubility (76.5%), water-holding capacity (266.8%), emulsifying index (66.8%), hemocompatibility (erythrocyte protection > 87%), and cytocompatibility (cell viability > 80% on RAW264.7 and keratinocyte HaCaT cells) at higher concentrations and prolongs coagulation time in APTT and PT tests. Our research unveils the significant biocompatibility of VITP14 EPS for synthesizing a variety of biomaterials.

VARIASI SUMBER KARBON TERHADAP PRODUKSI BIOSURFAKTAN OLEH BAKTERI HALOFILIK ISOLAT TAMBAK GARAM KAJHU ACEH BESAR

This research has isolated one type of halophilic bacterial strain from the salt pond of Kajhu Village with the code KJ-AB2. This bacterium grew optimally at 10% (w/v) NaCl so it was classified as moderate halophilic bacteria. Several types of halophilic bacteria are known to produce biosurfactants. Biosurfactants are surface active agents that are widely used in several pharmaceutical, food dan petroleum industries. The production of biosurfactants is strongly influenced by the type of carbon source used for bacterial growth. Olive oil, palm oil, sunflower oil, glucose dan glycerol are types of carbon sources used to see their effect in producing biosurfactants. This isolate growed well on the five carbon sources with an average OD600 2.001±0.293 at 72 hours of fermentation. Biosurfactant production was measured by oil spreading test (OST) every 24 hours until 120 hours of fermentation. The highest OST value was obtained when KJ-AB2 isolate was grown on biosurfactant production media using olive oil, sunflower oil dan palm oil with an average OST value of 5.6±0.6 cm, 4.7±0.6 cm, dan 4.6±0.7 cm, respectively.

Characterization of Halophilic Bacteria Isolated from Khewra Salt Mines

Halophilic bacteria can populate every niche of earth. These halophiles have a great potential of exopolysaccharides production that is of considerable importance in various industries. To screen EPS producing halophiles, saline soil samples were collected from Khewra salt mines, Jehlum, Pakistan. Twenty-two morphologically different bacterial strains were isolated by serial dilution method. All strains were considered as moderate halophilic bacteria as they could grow at 3-15% of NaCl concentration whereas only three strains could grow at 15% of NaCl, which belonged to the genus Bacillus and Pseudomonas. For screening of EPS production, P-medium was used. While for the estimation of slime production, congo-red agar was used that exhibited positive results by appearance of black colored colonies by many strains. Moreover, EPS production was analyzed quantitatively and qualitatively. Isolated Staphylococcus and Bacillus species produced high amount of EPS (20g/L). “Moderate halophiles” play an important role in therapeutics, bioremediation, food and medicine, petroleum and tanning industries by producing EPS. Recently, growth of many agriculture crops has been improved by using beneficial halophiles in saline soils. Consequently, with the help of these beneficial halophiles we can give benefit to mankind

Isolation of an ectoine-producing Sinobaca sp. and identification of genes that are involved in ectoine biosynthesis.

A moderate halophilic bacterium that could accumulate ectoine and hydroxyectoine was isolated from soil near a salt mine and was identified as a Sinobaca sp. (designed strain H24) according to 16S rRNA gene sequence analysis. The bacterium grew well in the presence of 1-2M NaCl, while growth in a medium that contained 2M NaCl led to higher accumulation of ectoines. The yields of ectoine and hydroxyectoine by Sinobaca sp. H24 reached 11.27mg/l and 1.34mg/l, respectively, when cultured in the following medium: NaCl (2M), peptone (5g/l), yeast extract (1g/l), NH4Cl (0.02M), KH2PO4 (1M), K2HPO4 (0.1M), and glycerol (1%w/v). Genes that are involved in ectoine biosynthesis of Sinobaca sp. H24 were also identified, and their sequences were determined by a metagenomics approach. The results demonstrated that Sinobaca sp. H24 possesses ectoine metabolism genes for both ectoine biosynthesis (ectA, ectB, ectC, and ectD) and ectoine degradation (doeA). Genes that are related to ectoine biosynthesis, such as lysC and asd, were also characterized. The identification and characterization results for ectoine/hydroxyectoine biosynthesis genes are in agreement with the physiology of Sinobaca sp. H24 as a potential candidate for ectoine production for industrial applications. This report established for the first time the accumulation of ectoine/hydroxyectoine in Sinobaca sp. and characterized the genes that are involved in ectoine/hydroxyectoine biosynthesis in Sinobaca sp. H24.

Adaptation to Varying Salinity in Halomonas elongata: Much More Than Ectoine Accumulation.

The halophilic γ-proteobacterium Halomonas elongata DSM 2581T thrives at salt concentrations well above 10 % NaCl (1.7 M NaCl). A well-known osmoregulatory mechanism is the accumulation of the compatible solute ectoine within the cell in response to osmotic stress. While ectoine accumulation is central to osmoregulation and promotes resistance to high salinity in halophilic bacteria, ectoine has this effect only to a much lesser extent in non-halophiles. We carried out transcriptome analysis of H. elongata grown on two different carbon sources (acetate or glucose), and low (0.17 M NaCl), medium (1 M), and high salinity (2 M) to identify additional mechanisms for adaptation to high saline environments. To avoid a methodological bias, the transcripts were evaluated by applying two methods, DESeq2 and Transcripts Per Million (TPM). The differentially transcribed genes in response to the available carbon sources and salt stress were then compared to the transcriptome profile of Chromohalobacter salexigens, a closely related moderate halophilic bacterium. Transcriptome profiling supports the notion that glucose is degraded via the cytoplasmic Entner-Doudoroff pathway, whereas the Embden-Meyerhoff-Parnas pathway is employed for gluconeogenesis. The machinery of oxidative phosphorylation in H. elongata and C. salexigens differs greatly from that of non-halophilic organisms, and electron flow can occur from quinone to oxygen along four alternative routes. Two of these pathways via cytochrome bo' and cytochrome bd quinol oxidases seem to be upregulated in salt stressed cells. Among the most highly regulated genes in H. elongata and C. salexigens are those encoding chemotaxis and motility proteins, with genes for chemotaxis and flagellar assembly severely downregulated at low salt concentrations. We also compared transcripts at low and high-salt stress (low growth rate) with transcripts at optimal salt concentration and found that the majority of regulated genes were down-regulated in stressed cells, including many genes involved in carbohydrate metabolism, while ribosome synthesis was up-regulated, which is in contrast to what is known from non-halophiles at slow growth. Finally, comparing the acidity of the cytoplasmic proteomes of non-halophiles, extreme halophiles and moderate halophiles suggests adaptation to an increased cytoplasmic ion concentration of H. elongata. Taken together, these results lead us to propose a model for salt tolerance in H. elongata where ion accumulation plays a greater role in salt tolerance than previously assumed.

EFFECT OF CALCIUM IONS TO THE ACTIVITY AND STABILITY OF EXTRACELLULAR LIPASE PRODUCED BY MODERATE HALOPHILIC BACTERIA Halomonas meridiana BK-AB4

This study reported the isolation and biochemical studies of extracellular lipase produced by a moderate halophilic bacterium, Halomonas meridiana BK-AB4. The estimated molecular weight of the lipase BK-AB4 is about 50 kDa. The study of metal ions effect to the enzyme activity revealed the strong dependency towards the presence of Ca2+ ion. Further studies showed that the optimum pH of the enzyme was similar in the presence and the absence of Ca2+ ions. However, the presence of Ca2+ ions could improve the enzyme thermal stability as indicated by the shift of its optimum temperature from 45°C - 50°C. The addition of Ca2+ ions was also enhancing residual activity towards various inhibitors, such as SDS and PMSF up to 55% and 68%, respectively. Another interesting effect of the addition of Ca2+ ions were noted when various organic solvents were added to the enzyme solution in the ratio of 1:1. The activity of the enzyme increased up to 122% and 126% relative to the control when methanol and n-butanol were added, respectively. This study thus showed that the addition of Ca2+ ion not only improved the catalytic activity of lipase BK-AB4 but also made the enzyme more tolerable against various perturbations.

Cloning, Bioinformatics and Activity Analysis of the MnhB Gene from the Moderately Halophilic Bacterium Halobacillus Y5

Cloning, Bioinformatics and Activity Analysis of the MnhB Gene from the Moderately Halophilic Bacterium Halobacillus Y5

Benefits of understanding the enzymatic activities in saline Lake Letea in the Danube Delta

The purpose of this paper was to isolate halophiles from Letea saline lake and to performed a screening for industrially relevant extracellular enzymes. The investigations were conducted from October 2016 until May 2018. After a random selection of colonies that grew on the medium culture, 82 isolates were investigated. Based on their salt requirements and tolerance, it was remarked the presence of isolates belonging to halotolerant and moderate halophilic bacteria. Morphological and biochemical tests were used to characterize them. The ability of the tested isolates to produce extracellular enzymes was evaluated on the culture medium with salinity varying between 0-4M and supplemented with a specific substrate. The highest hydrolytic activities were recorded for casein at 0M NaCl, 1M NaCl, 2M NaCl, and Tween 80 and inulin at 0M NaCl, 1M NaCl, 2M NaCl, and 3M NaCl.

Moderate Halophilic Lactic Acid Bacteria from Jambal roti: A Traditional Fermented Fish of Central Java, Indonesia

ABSTRACT Jambal rotiis a traditional salted-fermented product made from Arius thalassinus, which is a popular fish in Central Java Province, Indonesia. This research aimed to identify the moderate halophilic lactic acid bacteria isolated from jambal roti. The study began with enrichment culture (with MRS media and 5% NaCl) and isolation of lactic acid bacteria (LAB) using streak plate method. After the isolation, the isolate was identified using API 50 CHL kit (for phenotypic characteristic) and 16s rRNA gene sequence analysis (for genotypic characteristic). Eight pure isolates were identified from the fermented fish product. Most isolates (87.5%) were cocci (tetrad and pair), while the rest (1 isolated) was Lactobacillus (rod-shaped). All of which were moderate halophilic LAB. The isolates were selected based on their high proteolytic activity (quantitative) and R-value (qualitative). The analysis using API 50 CHL kit showed that all isolates were identified as Pediococcus pentosaceus 2 (99.9%), while further identification by repetitive PCR revealed three types of band profiles. In the 16s rRNA gene sequence analysis, three isolates were identified as Pediococcus acidilactici (strain no 306, 315, and 332), four isolates were identified as Pediococcus pentosaceus (strain no 312, 326, 328, and 339), and the other was identified as Lactobacillus plantarum (strain no 307). Moderate halophilic lactic acid bacteria isolated from Jambal roti were Pediococcus acidilactici, Pediococcus pentosaceus, and Lactobacillus plantarum.

Phylogenetic characterization and screening of halophilic bacteria from Algerian salt lake for the production of biosurfactant and enzymes

Environments containing significant concentration of NaCl such as salt lakes harbor extremophiles microorganisms which have a great biotechnology interest. To explore the diversity of Bacteria in Chott Tinsilt (Algeria), an isolation program was performed. Water samples were collected from the saltern during the pre-salt harvesting phase. This Chott is high in salt (22.47% (w/v). Seven halophiles Bacteria were selected for further characterization. The isolated strains were able to grow optimally in media with 10–25% (w/v) total salts. Molecular identification of the isolates was performed by sequencing the 16S rRNA gene. It showed that these cultured isolates included members belonging to the Halomonas, Staphylococcus, Salinivibrio, Planococcus and Halobacillus genera with less than 98% of similarity with their closest phylogenetic relative. The halophilic bacterial isolates were also characterized for the production of biosurfactant and industrially important enzymes. Most isolates produced hydrolases and biosurfactants at high salt concentration. In fact, this is the first report on bacterial strains (A4 and B4) which were a good biosurfactant and coagulase producer at 20% and 25% ((w/v)) NaCl. In addition, the biosurfactant produced by the strain B4 at high salinity (25%) was also stable at high temperature (30-100°C) and high alkalinity (pH 11).

Isolasi dan Karakterisasi Morfologi Bakteri Halofilik dari Bledug Kuwu, Kabupaten Grobogan

Bledug Kuwu is an area that has a fairly high salt content, this is caused by sea water trapped in the sedimentation process around the 18th century. Microorganisms that are able to live in extreme areas tend to have typical metabolic activities and can be utilized in industry. The purpose of this study was to characterize microbiologically, bacteria isolated from Bledug Kuwu, Kradenan District, Grobogan Regency, Central Java. The method used in this study was isolation on LB + NaCl media with NaCl levels of 10%, 12.5% and 15%. Characterization was done by Gram staining and motility test. The results obtained in samples from 3 sources, namely teak water, salt water and mud water, obtained 8 pure isolates. The seven isolates have the ability to grow optimally at 10% NaCl concentration so that these bacteria can be classified as moderate halophilic bacteria with the majority of species being coccus, Gram positive, and non motile.

Nature and bioprospecting of haloalkaliphilics: a review.

The haloalkaliphilics are an important subset of extremophiles that grow in salt [upto 33% (wt/vol) NaCl] and alkaline pH (> 9). They are found in hypersaline environments especially in the brines in arid, coastal and deep sea locations, and in alkaline environments, such as soda soils, lakes and deserts. Some authors have described haloalkaliphilic bacteria as moderate halophilic bacteria, but the molecular and classical studies revealed that they belong to moderately to extremely halophilic bacteria and archaea. Organic solutes, such as glycine, betaine and other amino acid derivatives, sugars such as, sucrose and trehalose, and sugar alcohols present in the haloalkaliphilics help for their osmoadaptation, and also serve as stabilizers. Haloalkalphilics secrete exoenzymes like proteases, amylases, xylanases, cellulases and peroxidases which have potential industrial applications. They also produce bacteriorhodopsin, compatible solutes, pigments, biopolymers, secondary metabolites like biosurfactants, polyhydroxyalkanoate (PHA) and exopolysaccharides and antimicrobial/anticancer compounds. They have unique metabolic pathways which can be used to treat industrial pollutants, heavy metals and waste water.

Correction to: Description of Wenzhouxiangella salilacus sp. nov., a moderate halophilic bacterium isolated from a salt lake in Xinjiang Province, China.

In the original publication of the article, the deposit accession numbers of strain 15181T in the acknowledgment section were incorrectly provided as "KCTC 62172T and MCCC 1K03442T".

Isolation and identification of indole acetic acid producing bacteria from the coasts of Ben Tre and Tra Vinh Provinces

Beneficial plant-growth-promoting bacteria (PGPB) have been reasonably applied to rescue crucial issue for agriculture by salinity soil. Observed most of PGPB was found in endophyte, rhizosphere and soil. Indole acetic acid (IAA)-producing bacteria could naturally stimulate and facilitate plant growth. The knowledge of IAA production and content of bacteria resident in the marine environment has been typically insufficient and limited to date. In recent years, unwarrantable intrusions of sea water have been enlarged in the Mekong River Delta of Vietnam, threatening productive rice fields, local fruits, and cash crops. Therefore, finding PGPB in the coastal regions in the Mekong River Delta as a creative resource for sustainable agriculture is necessary and is a prompt challenge. In this study, IAA-producing bacteria from coastal regions of Ben Tre and Tra Vinh Provinces were isolated and adequately identified. Out of 202 bacterial isolates, 10 isolates showed the possible ability to produce IAA from L-tryptophan. These 10 isolates were objectively evaluated the capacity to produce IAA under 5% (w/v) NaCl in King B and marine broths. The results revealed that IAA production decreased in 5% NaCl, even though bacterial growth increased. These 10 IAA-producing bacteria were classified at the species level, Marinobacter hydrocarbonoclasticus, M. pelagius, M. daepoensis, and Mameliella phaeodactyli by 16S rRNA gene analysis. The most IAA producer in King’s B broth, the isolate C7, was investigated in more detail. The isolate C7 produced the maximum IAA amount (192.2 ± 1.14 µg/ml) under the presence of 20 g/l yeast extract, 2 g/l of L-tryptophan and 1% NaCl. The isolate C7 was able to grow at 1–17% (w/v) NaCl (optimum, 4%), but not in the absence of NaCl, indicating it is a moderate halophilic bacteria. This study highlighted the considerable ability to produce IAA of marine bacteria, which could be thoughtfully considered to use naturally as biofertilizers to promote plant growth in saline intrusion lands.

Isolation and identification of indole acetic acid producing bacteria from the coasts of Ben Tre and Tra Vinh Provinces

Beneficial plant-growth-promoting bacteria (PGPB) have been reasonably applied to rescue crucial issue for agriculture by salinity soil. Observed most of PGPB was found in endophyte, rhizosphere and soil. Indole acetic acid (IAA)-producing bacteria could naturally stimulate and facilitate plant growth. The knowledge of IAA production and content of bacteria resident in the marine environment has been typically insufficient and limited to date. In recent years, unwarrantable intrusions of sea water have been enlarged in the Mekong River Delta of Vietnam, threatening productive rice fields, local fruits, and cash crops. Therefore, finding PGPB in the coastal regions in the Mekong River Delta as a creative resource for sustainable agriculture is necessary and is a prompt challenge. In this study, IAA-producing bacteria from coastal regions of Ben Tre and Tra Vinh Provinces were isolated and adequately identified. Out of 202 bacterial isolates, 10 isolates showed the possible ability to produce IAA from L-tryptophan. These 10 isolates were objectively evaluated the capacity to produce IAA under 5% (w/v) NaCl in King B and marine broths. The results revealed that IAA production decreased in 5% NaCl, even though bacterial growth increased. These 10 IAA-producing bacteria were classified at the species level, Marinobacter hydrocarbonoclasticus, M. pelagius, M. daepoensis, and Mameliella phaeodactyli by 16S rRNA gene analysis. The most IAA producer in King’s B broth, the isolate C7, was investigated in more detail. The isolate C7 produced the maximum IAA amount (192.2 ± 1.14 µg/ml) under the presence of 20 g/l yeast extract, 2 g/l of L-tryptophan and 1% NaCl. The isolate C7 was able to grow at 1–17% (w/v) NaCl (optimum, 4%), but not in the absence of NaCl, indicating it is a moderate halophilic bacteria. This study highlighted the considerable ability to produce IAA of marine bacteria, which could be thoughtfully considered to use naturally as biofertilizers to promote plant growth in saline intrusion lands.