Wide Range Of NaCl Concentrations Research Articles

Bismuth Nanoparticles Encapsulated in a Porous Carbon Skeleton as Stable Chloride-Storage Electrodes for Seawater Desalination

Cost-effective bismuth (Bi) boasts a high theoretical capacity and exceptional selectivity towards Cl- ion storage, making it a promising material for desalination batteries (DBs). However, the substantial volume expansion and low conductivity severely hinder the cycling performance of Bi-based DBs. In this study, a carbon-layer-coated Bi nanocomposite (Bi@C) was synthesized by pyrolyzing a metal–organic framework (Bi-MOF) containing Bi using a straightforward method. The results show that the Bi@C synthesized under the condition of annealing at 700 °C for 2 h has the optimum properties. The Bi@C has good multiplication performance, and the desalination capacity is 106.1 mg/g at a high current density of 1000 mA/g. And the material exhibited a high desalination capacity of 141.9 mg/g at a current density of 500 mA/g and retained 66.9% of its capacity after 200 cycles. In addition, the Bi@C can operate at a wide range of NaCl concentrations from 0.05 to 2 mol/L. The desalination mechanism analysis of the Bi@C revealed that the carbon coating provides space for Bi particles to expand in volume, thereby mitigating the issues of electrode material powdering and shedding. Meanwhile, the porous carbon skeleton establishes electron and ion channels to enhance the electrode material’s conductivity. This research offers a promising strategy for the application of chloride-storage electrode materials in electrochemical desalination systems.

Anaerobic biodegradation of azo dye reactive black 5 by a novel strain Shewanella sp. SR1: Pathway and mechanisms

The efficiency of microbial populations in degrading refractory pollutants and the impact of adverse environmental factors often presents challenges for the biological treatment of azo dyes. In this study, the genome analysis and azo dye Reactive Black 5 (RB5) degrading capability of a newly isolated strain, Shewanella sp. SR1, were investigated. By analyzing the genome, functional genes involved in dye degradation and mechanisms for adaptation to low-temperature and high-salinity conditions were identified in SR1. The addition of co-substrates, such as glucose and yeast extract, significantly enhanced RB5 decolorization efficiency, reaching up to 87.6%. Notably, SR1 demonstrated remarkable robustness towards a wide range of NaCl concentrations (1–30 g/L) and temperatures (10–30 °C), maintaining efficient decolorization and high biomass concentration. The metabolic pathways of RB5 degradation were deduced based on the metabolites and genes detected in the genome, in which the azo bond was first cleaved by FMN-dependent NADH-azoreductase and NAD(P)H-flavin reductase, followed by deamination, desulfonation, and hydroxylation mediated by various oxidoreductases. Importantly, the degradation metabolites exhibited reduced toxicity, as revealed by toxicity analysis. These findings highlighted the great potential of Shewanella sp. SR1 for bioremediation of wastewaters contaminated with azo dyes.

Heterologous expression and characterization of salt-tolerant β-glucosidase from xerophilic Aspergillus chevalieri for hydrolysis of marine biomass.

A salt-tolerant exo-β-1,3-glucosidase (BGL_MK86) was cloned from the xerophilic mold Aspergillus chevalieri MK86 and heterologously expressed in A. oryzae. Phylogenetic analysis suggests that BGL_MK86 belongs to glycoside hydrolase family 5 (aryl-phospho-β-D-glucosidase, BglC), and exhibits D-glucose tolerance. Recombinant BGL_MK86 (rBGL_MK86) exhibited 100-fold higher expression than native BGL_MK86. rBGL_MK86 was active over a wide range of NaCl concentrations [0%-18% (w/v)] and showed increased substrate affinity for p-nitrophenyl-β-D-glucopyranoside (pNPBG) and turnover number (kcat) in the presence of NaCl. The enzyme was stable over a broad pH range (5.5-9.5). The optimum reaction pH and temperature for hydrolysis of pNPBG were 5.5 and 45°C, respectively. rBGL_MK86 acted on the β-1,3-linked glucose dimer laminaribiose, but not β-1,4-linked or β-1,6-linked glucose dimers (cellobiose or gentiobiose). It showed tenfold higher activity toward laminarin (a linear polymer of β-1,3 glucan) from Laminaria digitata than laminarin (β-1,3/β-1,6 glucan) from Eisenia bicyclis, likely due to its inability to act on β-1,6-linked glucose residues. The β-glucosidase retained hydrolytic activity toward crude laminarin preparations from marine biomass in moderately high salt concentrations. These properties indicate wide potential applications of this enzyme in saccharification of salt-bearing marine biomass.

Characterization of trehalolipid biosurfactant produced by the novel marine strain Rhodococcus sp. SP1d and its potential for environmental applications

BackgroundBiosurfactants are surface-active compounds with environmental and industrial applications. These molecules show higher biocompatibility, stability and efficiency compared to synthetic surfactants. On the other hand, biosurfactants are not cost-competitive to their chemical counterparts. Cost effective technology such as the use of low-cost substrates is a promising approach aimed at reducing the production cost. This study aimed to evaluate the biosurfactant production and activity by the novel strain Rhodococcus sp. SP1d by using different growth substrates. Therefore, to exploit the biosurfactant synthesized by SP1d for environmental applications, the effect of this compound on the bacteria biofilm formation was evaluated. Eventually, for a possible bioremediation application, the biosurfactant properties and its chemical characteristics were investigated using diesel as source of carbon.ResultsRhodococcus sp. SP1d evidence the highest similarity to Rhodococcus globerulus DSM 43954T and the ability to biosynthesize surfactants using a wide range of substrates such as exhausted vegetable oil, mineral oil, butter, n-hexadecane, and diesel. The maximum production of crude biosurfactant after 10 days of incubation was reached on n-hexadecane and diesel with a final yield of 2.38 ± 0.51 and 1.86 ± 0.31 g L− 1 respectively. Biosurfactants produced by SP1d enhanced the biofilm production of P. protegens MP12. Moreover, the results showed the ability of SP1d to produce biosurfactants on diesel even when grown at 10 and 18 °C. The biosurfactant activity was maintained over a wide range of NaCl concentration, pH, and temperature. A concentration of 1000 mg L− 1 of the crude biosurfactant showed an emulsification activity of 55% towards both xylene and olive oil and a reduction of 25.0 mN m− 1 of surface tension of water. Eventually, nuclear magnetic resonance spectroscopy indicated that the biosurfactant is formed by trehalolipids.ConclusionsThe use of low-cost substrates such as exhausted oils and waste butter reduce both the costs of biosurfactant synthesis and the environmental pollution due to the inappropriate disposal of these residues. High production yields, stability and emulsification properties using diesel and n-hexadecane as substrates, make the biosurfactant produced by SP1d a sustainable biocompound for bioremediation purpose. Eventually, the purified biosurfactant improved the biofilm formation of the fungal antagonistic strain P. protegens MP12, and thus seem to be exploitable to increase the adherence and colonization of plant surfaces by this antagonistic strain and possibly enhance antifungal activity.

Engineering Synechococcus sp. PCC 7002 for sustainable production of sucrose

Sucrose is a readily available substrate and feedstock for biotechnology, which is biosynthesized by plants, algae, and cyanobacteria. Engineered cyanobacteria with enhanced sucrose production may be a viable alternative to sucrose synthesis from plants. The marine cyanobacteria which can be cultivated in seawater have the potential to provide a sustainable solution. The model marine cyanobacterium Synechococcus sp. PCC 7002 (Syn7002) has many features for a good chassis, including a fast growth rate and a wide range of stress tolerances. Syn7002 synthesizes mainly glucosylglycerol and traces of sucrose as compatible solutes under salt stress. The compatible solute glucosylglycerate was also found in small amounts in Syn7002. To enhance sucrose production in Syn7002, the sucrose biosynthesis genes and the sucrose transporter gene were overexpressed. And the competing pathway genes and the sucrose hydrolysis gene were inactivated. The sucrose production in the engineered strain can reach 2282 mg/L in 8 days under 1 M NaCl stress. With the further substitution of sucrose biosynthesis genes from Synechocystis sp. PCC 6803, the engineered strain can efficiently produce sucrose over a wide range of NaCl concentrations. The efficient sucrose production by marine cyanobacteria will promote the sustainable supply of sugar feedstocks for biotechnology and aquaculture.

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.

Flow Cytometric Investigation of Salinicola halophilus S28 Physiological Response Provides Solid Evidence for Its Uncommon and High Ability to Face Salt-Stress Conditions

In a previous work, some bacterial strains isolated from the Saline di Tarquinia marine salterns (Viterbo, Italy) showed very unusual growth profiles in relation to temperature and salinity variations when grown in solid media. In particular, Salinicola halophilus S28 showed optimal or suboptimal growth in a very wide range of NaCl concentrations, suggesting a great coping ability with salinity variations. These intriguing outcomes did not fit with the general Salinicola halophilus description as a moderately halophilic species. Therefore, this study profiles the actual physiological status of S28 cells subjected to different NaCl concentrations to provide evidence for the actual coping ability of strain S28 with broad salinity variations. Flow cytometry was selected as the evaluation method to study the physiological status of bacterial cells subjected to different salinity levels, monitoring the strain response at different growth phases over 72 h. Strain S28 showed maximal growth at 8% NaCl; however, it grew very well with no statistically significant differences at all salinity conditions (4–24% NaCl). Flow cytometric results provided clear evidence of its actual and strong ability to face increasing salinity, revealing a good physiological response up to 24% of NaCl. In addition, strain S28 showed very similar cell physiological status at all salinity levels, as also indicated by the flat growth profile revealed in the range of 4–24% NaCl. This is the first study regarding the physiological response during the growth of halophilic bacteria under different conditions of salinity via flow cytometry. This technique represents an effective tool for the investigation of the physiological status of each cell, even if it is somehow underrated and underused by microbiologists for this purpose.

Identification and characterization of <italic>Dunaliella salina</italic> OH214 strain newly isolated from a saltpan in Korea

Carotenoids are effective antioxidants that are found in various photosynthetic organisms. Marine microalgae are an advantageous bioresource for carotenoid production because they do not compete with other crops for freshwater and arable land. This study reports a newly isolated Dunaliella strain from the Geumhong Saltpan on Yeongjong Island, West Sea, Korea. The new strain was isolated and classified as Dunaliella salina through phylogenetic analysis and was named the OH214 strain (Deposit ID: KCTC14434BP). The newly isolated strain can survive in a wide range of NaCl concentrations (0.3−5.0 M NaCl), but grows well in 0.6 to 1.5 M NaCl culture medium. Under high-light conditions (500 ± 10 μmol photons m<sup>-2</sup> s<sup>-1</sup>), the cells accumulated three times more β-carotene than under low-light conditions (50 ± 5 μmol photons m<sup>-2</sup> s<sup>-1</sup>). The cells accumulated 2.5-fold more β-carotene under nitrogen-deficient (1 mM KNO<sub>3</sub>) conditions (3.24 ± 0.36 μg 106 cells<sup>-1</sup>) than in nitrogen-sufficient conditions (>5 mM KNO<sub>3</sub>). The lutein content under nitrogen-deficient conditions (1.73 ± 0.09 μg 106 cells<sup>-1</sup>) was more than 24% higher than that under nitrogen-sufficient conditions. Under the optimized culture condition for carotenoid induction using natural seawater, D. salina OH214 strain produced 7.97 ± 0.09 mg g DCW<sup>-1</sup> of β-carotene and 4.65 ± 0.18 mg g DCW<sup>-1</sup> of lutein, respectively. We propose that this new microalga is a promising strain for the simultaneous production of β-carotene and lutein.

Native Production of Prodigiosin in the Estuarine Bacterium, Vibrio gazogenes PB1, and Identification of the Associated pig Genes

Vibrio gazogenes PB1 is an estuarine bacterium that was first isolated from saltwater mud. This bacterial species possesses the metabolic capacity to produce prodigiosin which has potential uses as an anticancer agent, antibiotic, and a fungicide. We evaluated the feasibility of employing V. gazogenes PB1 as a bacterial host for the production of prodigiosin. V. gazogenes PB1 could be grown and maintained using the well-known lysogeny broth medium when supplemented with NaCl, and revived after storage at -80°C. Under batch conditions, growth of V. gazogenes PB1 in minimal media and production of prodigiosin was observed over a wide range of NaCl concentrations from 1 to 5% (w/v). The production of prodigiosin was significantly influenced by the concentration of glucose (as the carbon source), ammonium chloride (as the nitrogen source), inorganic phosphate ions, as well as pH. The greatest titer (231 mg/L) was observed in minimal media that contained 1% (w/v) glucose, 100 mM ammonium chloride and 100 mM potassium phosphate buffer. The sequences and chromosomal locations of the pig genes associated with prodigiosin biosynthesis are revealed for the first time. PigA is an isolated gene on chromosome 2, while the remaining pig genes, from pigB to pigN, exist as a 20 kb gene cluster on chromosome 1. Given its excellent growth in a range of NaCl concentrations, wide availability from culture collections and low-risk status for experimental work, we would conclude that V. gazogenes PB1 is a promising bacterial host for the production of prodigiosin.

Hyper production of polyhydroxyalkanoates by a novel bacterium Salinivibrio sp. TGB11

Strains of Salinivibrio genus are able to grow under wide range of NaCl concentration. Salinivibrio sp. TGB11, a novel bacterium screened from saltworks, was found capable of producing polyhydroxyalkanoates from sugars and volatile fatty acids. In shake flask cultures, the use of glucose, sucrose, acetate, and butyrate achieved poly(3-hydroxybutyrate) (PHB) titers of 5.00, 3.23, 0.77, and 0.88 g/L, respectively. The addition of 0.5 g/L propionate with glucose yielded 4.38 g/L poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), with a 3-hydroxyvalerate monomer content of 8.57 mol%, yet propionate concentration higher than 1.5 g/L severely inhibited cell growth. In fed-batch bioreactor studies, PHB titer of 100.22 g/L and PHBV titer of 59.30 g/L were achieved. The PHB production yield was 0.42 g/g, reaching 88% of the theoretical value. Salinivibrio sp. TGB11 showed the highest PHB titer and yield in Salinivibrio genus and could be a promising host for industrial purposes.

The functional starter and its genomic insight for histamine degradation in fish sauce

Histamine is a biogenic amine significantly formed in fish sauce leading to a major concern in consumers. This study aimed to identify a halophilic bacterium for histamine degradation in fish sauce, and understand its genomic insight to enhance histamine degradation activity. We discovered the novel halophilic bacterium, Bacillus piscicola FBU1786, degrading histamine and other biogenic amines. Its histamine breakdown was growth-associated in a wide range of NaCl concentrations, pH, and temperature from 4% to 18%, 6.0 to 9.0, and 30 to 45 °C, respectively. Genome sequencing revealed the presence of Cu2+-binding oxidase-encoding genes and their heterologous expression with Cu2+ supplementation triggered histamine degradation in E. coli. The degree of histamine breakdown in B. piscicola FBU1786 could be enhanced by Cu2+ addition. Histamine degradation of the culture was evaluated in raw fish sauce mixtures to partially mimic the condition during fish sauce fermentation. Histamine degradation was suppressed to the extent of raw fish sauce, but could be restored by Cu2+ supplementation. Together, this study disclosed B. piscicola FBU1786 with the potent histamine degradation activity, identified Cu2+-binding oxidases responsible for histamine breakdown, and enhanced histamine degradation of the culture using Cu2+ supplementation.

Identification of an Amylomaltase from the Halophilic Archaeon Haloquadratum walsbyi by Functional Metagenomics: Structural and Functional Insights.

Amylomaltases are prokaryotic 4-α-glucanotransferases of the GH77 family. Thanks to the ability to modify starch, they constitute a group of enzymes of great interest for biotechnological applications. In this work we report the identification, by means of a functional metagenomics screening of the crystallization waters of the saltern of Margherita di Savoia (Italy), of an amylomaltase gene from the halophilic archaeon Haloquadratum walsbyi, and its expression in Escherichia coli cells. Sequence analysis indicated that the gene has specific insertions yet unknown in homologous genes in prokaryotes, and present only in amylomaltase genes identified in the genomes of other H. walsbyi strains. The gene is not part of any operon involved in the metabolism of maltooligosaccharides or glycogen, as it has been found in bacteria, making it impossible currently to assign a precise role to the encoded enzyme. Sequence analysis of the H. walsbyi amylomaltase and 3D modelling showed a common structure with homologous enzymes characterized in mesophilic and thermophilic bacteria. The recombinant H. walsbyi enzyme showed starch transglycosylation activity over a wide range of NaCl concentrations, with maltotriose as the best acceptor substrate compared to other maltooligosaccharides. This is the first study of an amylomaltase from a halophilic microorganism.

In-situ growth of manganese oxide on self-assembled 3D- magnesium hydroxide coated on polyurethane: Catalytic oxidation mechanism and application for Mn(II) removal

Novel integration of adsorption followed by catalytic oxidation is expected to be more beneficial for higher Mn(II) removal performance. We prepared self-assembled 3D flower-like Mg(OH)2 coated on granular-sized polyurethane (namely FMHP) via hydrothermal method at 120 °C under a facile synthesis route. The optimized material, FMHP prepared with 7 g MgO and 20 g polyurethane (FMH0.35P), achieved up to 351.2 mg g−1 Mn(II) removal capacity by Langmuir isotherm model. Besides, FMHP exhibited high Mn(II) removal in a wide range of NaCl concentration (0~0.1 M) and pH 2–9. Notably, through consecutive kinetics, BET, XPS, XRD, FESEM, and TEM analyses, it was found that the MnOx layer grows in-situ via ion exchange with Mg(II) on FMHP and further boosts the Mn(II) removal via catalytic oxidation during the Mn(II) removal process. Further, column experiments revealed that the FMH0.35P exhibited superior Mn(II) removal capacities up to 135.9 mg g−1 and highly compatible treatment costs ($0.062 m−3) compared to conventional chemical processes. The granular-sized FMH0.35P prepared by economic precursors and simple synthesis route revealed a high potential for Mn(II) containing water treatment due to its high removal capacities and easy operation.

The Functional Starter and its Genomic Insights for Histamine Degradation in Fish Sauce

Histamine is a biogenic amine significantly formed in fish sauce leading to a major concern in consumers. This study aimed to identify a halophilic culture for histamine degradation in fish sauce, and understand its genomic insights to enhance the histamine degradation activity. We discovered the novel halophilic bacterium, Bacillus piscicola FBU1786, degrading histamine and other biogenic amines. Its histamine breakdown was growth-associated in a wide range of NaCl concentrations, pH, and temperature from 4% to 18%, 6.0 to 9.0, and 30 to 45oC, respectively. Genome sequencing revealed the presence of Cu 2+ -binding oxidase-encoding genes and their heterologous expression with Cu 2+ supplementation triggered histamine degradation in E. coli . The degree of histamine breakdown in B . piscicola FBU1786 could be enhanced by Cu 2+ addition. Histamine degradation of the culture was evaluated in raw fish sauce mixtures to partially mimic the condition during fish sauce fermentation. Histamine degradation was suppressed to the extent of raw fish sauce. However, the degradation activity could be restored by Cu 2+ supplementation. Together, this study disclosed B. piscicola FBU1786 with the potent histamine degradation activity, identified Cu 2+ -binding oxidases responsible for histamine breakdown, and enhanced histamine degradation of the culture using Cu 2+ supplementation.

Silver Solubility in Supercritical Fluids in a Wide Range of NaCl Concentration (0.6–50 wt %)—Experimental and Thermodynamic Description

The solubility of Agcr has been measured in a 0.1m (mol·(kg H2O)−1) solution of HCl at a fixed hydrogen content (∼0.5m) as a function of NaCl concentration from 0.1 to 18m at temperatures ranging f...

Facile Fabrication of Fe3O4@poly(acrylic) Acid Based Ferrofluid with Magnetic Resonance Imaging Contrast Effect

AbstractMagnetic resonance imaging (MRI) has emerged as one of the most promising techniques, which employs nanoscience and imaging technology, for early diagnosis of the cancers. In this work, magnetic nanoparticles of Fe3O4@ poly(acrylic) acid (PAA) were synthesized using a low cost thermal decomposition method from iron ions precursor and utilized as a signal agent for MRI imaging. The Fe3O4 magnetic nanoparticles obtained from FeCl2.4H2O precursor at the reaction temperature of 315 °C in 1‐octadcene solvent are of spherical shape with average diameter of 8.4 nm and high saturation magnetization (Ms) of 60.05 emu/g. After phase transferred with PAA, the magnetic Fe3O4@PAA fluid is highly stable in a wide range of pHs solution (5 ‐ 9) and wide range of NaCl concentrations (50 ‐ 300 mM) with zeta potential of −35.7 mV. The prepared Fe3O4@PAA fluid showed noncytotoxicity to the Hep‐G2, MCF‐7, RD cancer cell line and Vero healthy cell line. MRI in‐vitro results showed that transverse relaxation rate r2 was around 158.4 mM−1s−1 and the signal intensity was not affected by the pHs solution and NaCl concentrations. In‐vivo test on rabbit revealed the clear observation of rabbit's body parts after injection of the Fe3O4@PAA magnetic fluid with retention time of 90 minutes in the body.

Colloidal stability of silver nanoparticles with layer-by-layer shell of chitosan copolymers

The influence of polymeric shell formed by the layer-by-layer (LbL) assembly technique using chitosan or its grafted copolymers with dextran or poly(ethylene glycol) and dextran sulfate on physico-chemical properties and aggregation kinetics of silver nanoparticles (AgNP) was investigated. It is shown that the hydrodynamic diameter of encapsulated AgNP increases linearly with increasing the number of polyelectrolyte layers without sufficient aggregation. The critical concentrations of coagulation (CCC) and Hamaker constants (H) were determined in dependence on electrolyte charge, structure of polycation, and number of bilayers in the shells. While a shell consists of more than two bilayers, the values of critical electrolyte concentration and energy of interparticle interactions H are influenced mainly by copolymer structure. In all cases, the CCC value is more than doubled after formation of two or more bilayers over silver nanoparticle surface. The shells based on chitosan-poly(ethylene glycol) graft copolymer were proven to be the most effective in increasing aggregation stability in NaCl solutions, while chitosan-dextran graft copolymer effectively decreases van der Waals interaction between nanoparticles. Application of grafted copolymers allows one to obtain encapsulated colloids that are stable over a wide range of NaCl concentrations including the isotonic one and improve biocompatibility and targetability of nanovehicles engineered for therapeutic or imaging purposes.

Isolation, characterisation and in vitro evaluation of bacteriocins-producing lactic acid bacteria from fermented products of Northern Borneo for their beneficial roles in food industry

In this study, lactic acid bacteria (LAB) isolated from traditional fermented foods namely coco bean, fermented cabbage, salted vegetable, tempeh, tempoyak, tapai ubi and tapai nasi were screened for production of bacteriocin. Characterisation and in vitro evaluation of them were carried out to assess their potential use in food industry. Towards these objectives, the inhibitory spectra of the isolates against Listeria monocytogenes ATCC13932, resistance to phenol, amylolytic and proteolytic activities, ability to produce acid and coagulate milk, antibiotic susceptibility and tolerance in the presence of various concentration of NaCl and at different temperatures were evaluated. Two out of 15 LAB strains were able to inhibit the growth of food-borne pathogen, L. monocytogenes ATCC 13932 and produce bacteriocin-like inhibitory substances. The strains were identified as Pediococcus acidilactici TN1 (from tapai nasi) and Lactobacillus farciminis TY1 (from tempoyak). Biochemical and physiological tests demonstrated that, both strains were able to grow at wide range of NaCl concentrations (0.5 - 5.0 %, w/v) and temperatures (28 - 70 °C), and capable to degrade protein. They lowered the pH level and coagulate milk after 24 h of incubation. Both strains showed intrinsic mechanisms of antibiotic resistance towards streptomycin, norfloxacin, erythromycin, amikacin and nalidixic acid. They also were able to grow in 0.3% (w/v) of bile salts and tolerate up to 0.5% (w/v) phenol. The findings from this study revealed the presence of LAB strains in fermented foods of Northern Borneo which have an antimicrobial activity towards the food-borne pathogen. Even though this study had generated extensive information to validate Pediococcus acidilactici TN1 and Lactobacillus farciminis TY1 as potential probiotic strains for application in the food industry, the study is by no means comprehensive nor complete. More laboratory, particularly in vivo studies, are needed before this product could be accepted by the food industry and most importantly to explore its novel health promoting functions as well as its colonization behaviour in the gut.

Determination of NaCl- induced modifications in growth processes and induction of programmed cell death in sunflower roots

Globally, about 30 % of all soils are damaged by salinity. Salinity leads to lower productivity of agro- and biocenosis, a decline in biodiversity and, as a result, significant economic losses. For the most important oil culture – sunflower (Helianthus annuus L.), primary reactions to salt stress are almost unexplored. This paper analyzes the impact of a wide range of NaCl concentrations on the growth of the main root of sunflower sprouts and the development of programmed cell death processes in trichoblasts. Experiments have shown that sunflower plants are relatively resistant to salinity (NaCl). They were able to grow at the level up to NaCl 250 mmol/L in the environment. Significant symptoms of programmed cell death were detected only at high concentrations of NaCl 250 –500 mmol/L. Previously undescribed in the literature, the reaction of reducing the number of symptoms of programmed cell death under150 mmol/L NaCl treatment (medium salt stress level for sunflower) was determined. An inhibitory analysis of the NaCl-induced potassium flux showed that it was only 15 % inhibited by specific potassium channel antagonists (Ba2+ ). This indicates a low proportion of potassium channels and the dominant role of non-selective cation channels in providing NaCl-induced potassium loss in Helianthus annuus L. plants.

Understanding the NaCl-dependent behavior of hydrogen production of a marine bacterium, Vibrio tritonius.

Biohydrogen is one of the most suitable clean energy sources for sustaining a fossil fuel independent society. The use of both land and ocean bioresources as feedstocks show great potential in maximizing biohydrogen production, but sodium ion is one of the main obstacles in efficient bacterial biohydrogen production. Vibrio tritonius strain AM2 can perform efficient hydrogen production with a molar yield of 1.7 mol H2/mol mannitol, which corresponds to 85% theoretical molar yield of H2 production, under saline conditions. With a view to maximizing the hydrogen production using marine biomass, it is important to accumulate knowledge on the effects of salts on the hydrogen production kinetics. Here, we show the kinetics in batch hydrogen production of V. tritonius strain AM2 to investigate the response to various NaCl concentrations. The modified Han–Levenspiel model reveals that salt inhibition in hydrogen production using V. tritonius starts precisely at the point where 10.2 g/L of NaCl is added, and is critically inhibited at 46 g/L. NaCl concentration greatly affects the substrate consumption which in turn affects both growth and hydrogen production. The NaCl-dependent behavior of fermentative hydrogen production of V. tritonius compared to that of Escherichia coli JCM 1649 reveals the marine-adapted fermentative hydrogen production system in V. tritonius. V. tritonius AM2 is capable of producing hydrogen from seaweed carbohydrate under a wide range of NaCl concentrations (5 to 46 g/L). The optimal salt concentration producing the highest levels of hydrogen, optimal substrate consumption and highest molar hydrogen yield is at 10 g/L NaCl (1.0% (w/v)).