The Characterization of Salt Tolerance in Biomining Microorganisms and the Search for Novel Salt Tolerant Strains

2009 ◽  
Vol 71-73 ◽  
pp. 283-286 ◽  
Author(s):  
Carla M. Zammit ◽  
L.A. Mutch ◽  
Helen R. Watling ◽  
Elizabeth L.J. Watkin

In this study an acidic saline drain in the Western Australian wheat belt was sampled and enriched for salt tolerant chemolithotrophic microorganisms in acidic media containing up to 100 gL-1 NaCl. A mixed consortium was obtained which grows at pH 1.8 and oxidises iron (II) in the presence of up to 30 gL-1 NaCl. In comparative tests (growth rates and iron (II) oxidation rates) it was found that NaCl concentrations >3.5 gL-1 generally cause reduced growth and iron (II) oxidation rates in known biomining organisms. The results help to set a benchmark for NaCl tolerance in known biomining microorganisms and will lead to the generation of a consortium of microorganisms that can oxidise iron (II) effectively in saline process water.

Biomolecules ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1287
Author(s):  
Zhiwei Yi ◽  
Zhengwen Cai ◽  
Bo Zeng ◽  
Runying Zeng ◽  
Guangya Zhang

β-1,3 xylanase is an important enzyme in the biorefinery process for some algae. The discovery and characterization of new β-1,3 xylanase is a hot research topic. In this paper, a novel β-1,3 xylanase (Xyl88) is revealed from the annotated genome of Flammeovirga pacifica strain WPAGA1. Bioinformatic analysis shows that Xyl88 belongs to the glycoside hydrolase 26 (GH26) with a suspected CBM (carbohydrate-binding module) sequence. The activity of rXyl88 is 75% of the highest enzyme activity (1.5 mol/L NaCl) in 3 mol/L NaCl buffer, which suggests good salt tolerance of rXy188. The optimum reaction temperature in the buffer without NaCl and with 1.5 mol/L NaCl is 45 °C and 55 °C, respectively. Notably, the catalytic efficiency of rXyl88 (kcat/Km) is approximately 20 higher than that of the thermophilic β-1,3 xylanase that has the highest catalytic efficiency. Xyl88 in this study becomes the most efficient enzyme ever found, and it is also the first reported moderately thermophilic and salt-tolerant β-1,3 xylanase. Results of molecular dynamics simulation further prove the excellent thermal stability of Xyl88. Moreover, according to the predicted 3D structure of the Xyl88, the surface of the enzyme is distributed with more negative charges, which is related to its salt tolerance, and significantly more hydrogen bonds and Van der Waals force between the intramolecular residues, which is related to its thermal stability.


2020 ◽  
Author(s):  
Jarina Joshi ◽  
Tribikram Bhattarai ◽  
Amar Yadav ◽  
Lakshmaiah Sreer

Abstract Yeasts are the mainstay in ethanol production industry. Search for efficient yeast strains that are salt tolerant and utilize both hexoses (glucose) and pentoses (xylose and arabinose) is important in fermentation industry. In this regard,12 yeast strains, viz., CDBT1-12, were isolated from various sources and characterized. Molecular characterization of the yeast strains was done by sequencing 26S rRNA gene, D1D2 region. Out of 12 isolates, 10 were found to be Saccharomyces cerevisiae , CDBT7 was Wikerhamomyces anomalous , and CDBT8 was Cyberlindnera fabianii . The yeast isolates were characterized in terms of their ethanol production efficiency, salt tolerance and ability to utilize of glucose and xylose. All the strains were found to be good ethanol producers. Yeast strain CDBT2 was found to have tolerance for high salt (up to 15%) and ethanol (up to 16%) concentrations. Yeast strain CDBT7 was found to utilize both glucose and xylose without compromising on ethanol production efficiency. The CDBT7 strain was also salt tolerant (up to15%).Yeast strain CDBT2 when grown in an electrochemical cell with low levels of applied external voltage, alcohol dehydrogenase (ADH1) and pyruvate decarboxylase (PDC1) mRNA levels were increased by 2.78 ± 0.80 and 1.12 ± 0.37 fold, respectively. We believe, the latter observation is novel and it has not been reported previously. It also further supports our previous observation of increase in level of alcohol production by CDBT2 strain in the presence of applied electrical current.


Author(s):  
Arti Sharma ◽  
Kamal Dev ◽  
Anuradha Sourirajan ◽  
Madhu Choudhary

Abstract Background Soil salinity has been one of the biggest hurdles in achieving better crop yield and quality. Plant growth-promoting rhizobacteria (PGPR) are the symbiotic heterogeneous bacteria that play an important role in the recycling of plant nutrients through phytostimulation and phytoremediation. In this study, bacterial isolates were isolated from salt-polluted soil of Jhajjar and Panipat districts of Haryana, India. The potential salt-tolerant bacteria were screened for their PGPR activities such as phosphate solubilization, hydrogen cyanide (HCN), indole acetic acid (IAA) and ammonia production. The molecular characterization of potent isolates with salt tolerance and PGPR activity was done by 16S rDNA sequencing. Results Eighteen soil samples from saline soils of Haryana state were screened for salt-tolerant bacteria. The bacterial isolates were analyzed for salt tolerance ranging from 2 to 10%. Thirteen isolates were found salt tolerant at varied salt concentrations. Isolates HB6P2 and HB6J2 showed maximum tolerance to salts at 10% followed by HB4A1, HB4N3 and HB8P1. All the salt-tolerant bacterial isolates showed HCN production with maximum production by HB6J2. Phosphate solubilization was demonstrated by three isolates viz., HB4N3, HB6P2 and HB6J2. IAA production was maximum in HB4A1 (15.89) and HB6P2 (14.01) and least in HB4N3 (8.91). Ammonia production was maximum in HB6P2 (12.3) and least in HB8P1 (6.2). Three isolates HB6J2, HB8P1 and HB4N3 with significant salt tolerance, and PGPR ability were identified through sequencing of amplified 16SrRNA gene and were found to be Bacillus paramycoides, Bacillus amyloliquefaciens and Bacillus pumilus, respectively. Conclusions The salt-tolerant plant growth-promoting rhizobacteria (PGPR) isolated from saline soil can be used to overcome the detrimental effects of salt stress on plants, with beneficial effects of physiological functions of plants such as growth and yield, and overcome disease resistance. Therefore, application of microbial inoculants to alleviate stresses and enhance yield in plants could be a low cost and environmental friendly option for the management of saline soil for better crop productivity.


Agronomy ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1703
Author(s):  
Francisco Gil-Muñoz ◽  
Nicolas Delhomme ◽  
Ana Quiñones ◽  
Maria del Mar Naval ◽  
Maria Luisa Badenes ◽  
...  

Agriculture needs solutions for adapting crops to increasing salinity globally. Research on physiological and molecular responses activated by salinity is needed to elucidate mechanisms of salinity tolerance. Transcriptome profiling (RNA-Seq) is a powerful tool to study the transcriptomic profile of genotypes under stress conditions. Persimmon species have different levels of tolerance to salinity, this variability may provide knowledge on persimmon species and development of salt--tolerant rootstocks. In this study, we conducted a physiological and transcriptomic profiling of roots and leaves in tolerant and sensitive plants of persimmon rootstock grown under saline and control conditions. Characterization of physiological responses along with gene expression changes in roots and leaves allowed the identification of several salt tolerance mechanisms related to ion transport and thermospermine synthesis. Differences were observed in putative H+/ATPases that allow transmembrane ionic transport and chloride channel protein-like genes. Furthermore, an overexpression of thermospermine synthase found in the roots of tolerant plants may indicate that alterations in root architecture could act as an additional mechanism of response to salt stress. These results indicate that Diospyros lotus L. exhibits genetically-controlled variability for salt tolerance traits which opens potential opportunities for breeding salt-tolerant persimmon rootstocks in a Mediterranean environment challenged by drought and salinity.


1970 ◽  
Vol 18 ◽  
pp. 34-39 ◽  
Author(s):  
M Salah Uddin ◽  
Zhou Jiti ◽  
MA Saleh ◽  
A Ekram ◽  
B Sikdar ◽  
...  

Context: Isolated plasmid DNA from salt tolerant bacteria can play an important role in special environmental conditions.   Objectives: The main objective of this study was to make a standard protocol for the isolation of large plasmid DNA from a highly salt tolerant bacterial strain, and then the plasmid DNA was eliminated from bacterial genome to know its effect on bacterial adaptation in high saline water.   Materials and Methods: The strain Gracilibacillus sp. GTY was collected from the coast line of Dalian (North China) and was inoculated in high salt concentrated bacteriological media. Wheatcroft’s modified method was used to isolate plasmid DNA. Then the chemical curing agents such as acridine orange, SDS, sodium benzoate and mitomycin C were applied separately in different concentrations to eliminate plasmid DNA. After the elimination of plasmid DNA, the strain was cultivated in the MS liquid media containing 5%, 15% and 25% (w/v) of NaCl respectively and their growth rates were compared with the non-eliminated culture.   Results: According to Wheatcroft’s modified method, the plasmid took two more hours to get isolated from the chromosomal DNA and the approximate size of the extracted plasmid DNA was 23.13 kb. Among all of the curing agents, plasmid DNA was eliminated successfully by acridine orange after 24 h of treatment at the concentration of 50 mg/l. Growth rates of plasmid eliminated culture were lower than non-eliminated culture and the growth rates of the plasmid eliminated culture were decreasing significantly with the addition of more NaCl.Conclusion: The results obtained in this study suggest that the presence of large plasmid DNA in salt tolerant bacteria is related to their survival strategies. The genes located in the large plasmids may encode important traits related to their adaptation to special environmental conditions.   Keywords: Salt tolerance; halophilic bacteria; curing agent; extrachromosomal DNA; Gracilibacillus sp. GTY. DOI: http://dx.doi.org/10.3329/jbs.v18i0.8772 JBS 2010; 18(0): 34-39


2019 ◽  
Author(s):  
Jarina Joshi ◽  
Tribikram Bhattarai ◽  
Amar Yadav ◽  
Lakshmaiah Sreer

Abstract Yeast are the mainstay in ethanol production industry. Search for efficient yeast strains that are salt tolerant and utilize both hexoses (glucose) and pentoses (xylose and arabinose) is important in fermentation industry. In this regard,12 yeast strains, viz., CDBT1-12, were isolated from various sources and characterized. Molecular characterization of the yeast strains was done by sequencing 26S rRNA gene, D1D2 region. Out of 12 isolates, 10 were found to be Saccharomyces cerevisiae , CDBT7 was Wikerhamomyces anomalous , and CDBT8 was Cyberlindnera fabianii . The yeast isolates were characterized in terms of their ethanol production efficiency, salt tolerance and ability to utilize of glucose and xylose. All the strains were found to be good ethanol producers. Yeast strain CDBT2 was found to have tolerance for high salt (up to 15%) and ethanol (up to 16%) concentrations. Yeast strain CDBT7 was found to utilize both glucose and xylose without compromising on ethanol production efficiency. The CDBT7 strain was also salt tolerant (up to15%).Yeast strain CDBT2 when grown in an electrochemical cell with low levels of applied external voltage, alcohol dehydrogenase (ADH1) and pyruvate decarboxylase (PDC1) mRNA levels were increased by 2.78 ± 0.80 and 1.12 ± 0.37 fold, respectively. We believe, the latter observation is novel and it has not been reported previously. It also further supports our previous observation of increase in level of alcohol production by CDBT2 strain in the presence of applied electrical current.


2013 ◽  
Vol 19 (2) ◽  
pp. 57-65
Author(s):  
MH Kabir ◽  
MM Islam ◽  
SN Begum ◽  
AC Manidas

A cross was made between high yielding salt susceptible BINA variety (Binadhan-5) with salt tolerant rice landrace (Harkuch) to identify salt tolerant rice lines. Thirty six F3 rice lines of Binadhan-5 x Harkuch were tested for salinity tolerance at the seedling stage in hydroponic system using nutrient solution. In F3 population, six lines were found as salt tolerant and 10 lines were moderately tolerant based on phenotypic screening at the seedling stage. Twelve SSR markers were used for parental survey and among them three polymorphic SSR markers viz., OSR34, RM443 and RM169 were selected to evaluate 26 F3 rice lines for salt tolerance. With respect to marker OSR34, 15 lines were identified as salt tolerant, 9 lines were susceptible and 2 lines were heterozygous. While RM443 identified 3 tolerant, 14 susceptible and 9 heterozygous rice lines. Eight tolerant, 11 susceptible and 7 heterozygous lines were identified with the marker RM169. Thus the tested markers could be efficiently used for tagging salt tolerant genes in marker-assisted breeding programme.DOI: http://dx.doi.org/10.3329/pa.v19i2.16929 Progress. Agric. 19(2): 57 - 65, 2008


HortScience ◽  
1997 ◽  
Vol 32 (2) ◽  
pp. 296-300 ◽  
Author(s):  
M.R. Foolad ◽  
G.Y. Lin

Seed of 42 wild accessions (Plant Introductions) of Lycopersicon pimpinellifolium Jusl., 11 cultigens (cultivated accessions) of L. esculentum Mill., and three control genotypes [LA716 (a salt-tolerant wild accession of L. pennellii Corr.), PI 174263 (a salt-tolerant cultigen), and UCT5 (a salt-sensitive breeding line)] were evaluated for germination in either 0 mm (control) or 100 mm synthetic sea salt (SSS, Na+/Ca2+ molar ratio equal to 5). Germination time increased in response to salt-stress in all genotypes, however, genotypic variation was observed. One accession of L. pimpinellifolium, LA1578, germinated as rapidly as LA716, and both germinated more rapidly than any other genotype under salt-stress. Ten accessions of L. pimpinellifolium germinated more rapidly than PI 174263 and 35 accessions germinated more rapidly than UCT5 under salt-stress. The results indicate a strong genetic potential for salt tolerance during germination within L. pimpinellifolium. Across genotypes, germination under salt-stress was positively correlated (r = 0.62, P < 0.01) with germination in the control treatment. The stability of germination response at diverse salt-stress levels was determined by evaluating germination of a subset of wild, cultivated accessions and the three control genotypes at 75, 150, and 200 mm SSS. Seeds that germinated rapidly at 75 mm also germinated rapidly at 150 mm salt. A strong correlation (r = 0.90, P < 0.01) existed between the speed of germination at these two salt-stress levels. At 200 mm salt, most accessions (76%) did not reach 50% germination by 38 days, demonstrating limited genetic potential within Lycopersicon for salt tolerance during germination at this high salinity.


1992 ◽  
Vol 57 (12) ◽  
pp. 2529-2538 ◽  
Author(s):  
Krasimir Ivanov ◽  
Penka Litcheva ◽  
Dimitar Klissurski

Mn-Mo-O catalysts with a different Mo/Mn ratio have been prepared by precipitation. The precipitate composition as a function of solution concentration and pH was studied by X-ray, IR, thermal and chemical methods. Formation of manganese molybdates with MnMoO4.1.5H2O, Mn3Mo3O12.2.5H2O, and Mn3Mo4O15.4H2O composition has been supposed. It is concluded that pure MnMoO4 may be obtained in both acid and alkaline media, the pH values depending on the concentration of the initial solutions. The maximum Mo/Mn ratio in the precipitates is 1.33. The formation of pure Mn3Mo4O15.4H2O is possible in weakly acidic media. This process is favoured by increasing the concentration of initial solutions.


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