Mehrnoush Daneshvar, Mahmood Maleki, Shahryar Shakeri, Amin Baghizadeh,
Volume 6, Issue 4 (1-2020)
Abstract
Phosphorus, the most essential nutrient for plants, becomes quickly unavailable for the plants in the soil. Phosphate solubilizing bacteria (PSB( can play an important role in providing Phosphorus for plants. In this study, the PSBs were screened from plant rhizosphere by Pikovskaya method. Then, the growth rate and phosphate solubilizing ability of 9 superior strains were measured at different temperatures and levels of salinity and pH. The best strain was identified by 16S rDNA gene sequence analysis. Finally, the genetic diversity of phosphate solubilizing strains were examined by RAPD markers. Results showed that 25 strains were capable of solubilizing insoluble phosphates among the 57 isolates studied. Of the nine superior strains, Cke1 had the highest solubilizing index with the average growth rate under all conditions and was introduced as the best PSB strain identified in the present study. 16S rDNA gene sequence analysis showed that this strain belonged to the Enterobacter genus. The results of genetic variation showed that all stains were divided into six groups and three strains that had the lowest similarity with other strains were placed in three separate groups. Given that Cke1 strain has the ability of solubilizing the insoluble phosphate in different stresses, it can be a good candidate for providing phosphorus at temperatures of 30 and 35 °C, 1.2% and 1.8% salinity levels and pH levels of 6 and 8 for the crops.
Asghar Mosleh Arany, Navid Nemati, Hengame Zandi, Mostafa Naderi,
Volume 6, Issue 4 (1-2020)
Abstract
The aim of this study was to evaluate the antibacterial activity of the water extracts of three species of Salvia (S. perspolitana, S. palaestina, S. bracteata) on Staphylococcus aureus, Escherichia coli and Pseudomonas aeroginosa. The antibacterial activity of water extracts of the studied species on the bacterial strains was examined using well diffusion method and minimum inhibitory concentration (MIC). Results showed that only S. bracteata formed growth inhibitory zone (9 mm) on Staphylococcus aureus. The extracts of all three plants formed growth inhibitory zone on E.coli and P. aeroginosa. The extract of S. bracteata was more effective than that of the other species. Results for MIC also showed that the extracts of S. perspolitana had the lowest effect on St. aureus and its MIC was observed in a concentration of 1024 µg/ml. The extracts of this species had the inhibitory effect in a concentration of 256 µg/ml. The uppermost inhibitory effect was provided by the extract of S. bracteata, since the minimum inhibitory concentration of this species for S. aureus was equal to 64 µg/ml; and for the other two bacteria, it was equal to 128 µg/ml. The extracts of S. palaestina had the lowest effect on S. aureus and its MIC was observed in a concentration of 1024 µg/ml. The extracts of this species had an MIC equal to 512 µg/ml for the other two bacteria. It was concluded that S. bracreata could be considered a suitable species with anti-bacterial activities in future researches.
Mina Maleki, Mohammad Pooya Naghshbandi, Zahra Hajihassan,
Volume 6, Issue 4 (1-2020)
Abstract
Magentotactic bacteria are the types of bacteria capable of orientation in an external magnetic field because of the ability to produce structures called magnetosomes. Magnetosomes, nanometer-scale structures, are present in most of the magnetotactice bacteria. They are intracellular organelles composed of magnetic iron mineral crystals individually surrounded by a phospholipid layer. Because of the unique features of magnetosomes, magentotactic bacteria have become the fascinating subject of research in many research and applied fields of study, including robotics, medicine, biology, environment and geology. In this review, we have tried to introduce magentotactic bacteria, the formation of magnetosomes and their structures, in order to highlight the importance of these bacteria. Finally, some applications of these bacteria in different areas of research, e.g. targeted drug delivery, cancer treatment and removal of heavy metals from water, were described in order that a better understanding of their applications could be obtained.
Elaheh Zadeh-Hosseingholi, Nader Chaparzadeh, Samira Mahmudi Aghdam,
Volume 6, Issue 4 (1-2020)
Abstract
Some rhizobacteria have positive effects on plants growth. Syrian bean-caper (Zygophyllum fabago) is a weed plant with medicinal value. This study was conducted to isolate and identify bacteria from Syrian bean-caper rhizosphere. Characteristics associated with plant growth stimulation, such as phosphate and zinc dissolution, production of Indole acetic acid and antifungal activity, were investigated. The isolates were separately inoculated to the plant and after plant root establishment was ensured, their effectiveness in increasing plant growth in greenhouse conditions was measured. Biochemical and molecular identification results showed that five isolates belonged to the genera Bacillus, Pseudomonas, Pantoea, and Brevibacterium. All five isolates showed some degree of plant growth promotion capabilities. Among the isolates, only the genus Bacillus increased the dry weights of plants significantly. The amount of phosphate solubilization for this isolate was 440 μg ml-1 and its acid production in the culture medium was higher than that in other isolates. The isolate had zinc solubilisation capability and produced 3.89 mg ml-1 indole acetic acid. However, this isolate did not show antifungal activity against two fungal pathogens of Aspergillus niger and Botrytis cinerea.
Khatereh Kabiri, Keivan Majidzadeh,
Volume 6, Issue 4 (1-2020)
Abstract
Yersinia pestis, a gram-negative rod belonging to the Enterobacteriaceae family, is the causative agent of plague. Classical methods of detecting the organisms are time-consuming, expensive and dangerous. The aim of the study was to design a Real-time PCR assay on the basis of the pla gene of Yersinia pestis. In this research the Real- time PCR test was optimized by using special primers for targeting pla gene. After preparing 10-fold serial dilutions of the pla and their analysis by the assay, the last dilution showing a fluorescent signal was confirmed as the limit of detection (LOD). A standard curve based on the Ct values was depicted, so the assay was developed to quantify the target gene. The analytical specificity was determined by subjecting the genome of some control negative bacteria to the assay. In this experiment, negative control genomes did not show detectable signals in the assay. The last dilution of pla plasmid which showed a fluorescent signal was 4.5 fg. So, the lower detectable copy numbers of the gene in a 20 μl PCR reaction was calculated as 1×103.
Vida Tafakori, Nasim Nasiri,
Volume 6, Issue 4 (1-2020)
Abstract
Plants have been used as medicines in the treatment of diseases from the past to present. In this research, the anti-microbial effects of aqueous and methanolic extracts of Erythrostemon gilliesii were studied. For this purpose, fresh flowers were ground and then macerated in methanol 100% and water overnight. After the evaporation of solvents, anti-microbial activities of the concentrated extracts were evaluated by the well-diffusion method on Klebsiella pneumoniae, Pseudomonas aeroginosa, Methicilin resistance, Staphylococcus aureus, Bacillus subtilis and Candida albicans. The results showed that the extracts were effective on different bacteria and yeasts. In order to determine the minimum inhibitory concentration (MIC) and minimum biocidal concentration (MBC), anti-microbial tests were performed in micro-plates. Subsequently, the results indicated that the extracts were stable at different temperatures. The aqueous and methanolic extracts of the flowers of E. gilliesii had exhibited anti-microbial effects against important infectious microbes and could be introduced as an excellent source for anti-microbial agents.
Samaneh Khosroshahi, Ensieh Salehghamari, Mohammad Ali Amoozegar, Parvaneh Saffarian,
Volume 6, Issue 4 (1-2020)
Abstract
Nowadays plant endophytic bacteria have found diverse and useful applications in biotechnology; therefore, much attention has been paid to the isolation, identification, and evaluation of these microorganisms. Since the sterilizing plant tissue surfaces from epiphytic bacteria is difficulty, the efficacy of three different screening methods for endophytic bacteria including 1- HClO sterilization, 2- Periodic sterilization (modified tyndallization) and 3- Triton X100 and HClO sterilization, was evaluated in this study. The modified Tyndallization is an innovative method used in this study to appropriately remove the internal spores of epiphytic bacteria, considered to be an obstacle to the isolation of endophytes. Most of the endophytic bacteria were isolated from dicotyledons and leaves. Endophytic bacteria were also studied for the production of different hydrolase enzymes, whereas the protease enzyme was produced in a wide range of endophytic bacteria in greater quantities than other enzymes. The EndoA strain was molecularly identified and found to be 100% similar to Bacillus halotolerans.
Pouria Khodavandi, Fahimeh Alizadeh, Alireza Khodavandi,
Volume 7, Issue 1 (4-2020)
Abstract
The occurrence of extended-spectrum beta-lactamases-producing bacteria is an important public health issue. The aim of this study was to investigate phenotypic and genotypic characteristics regarding the presence of extended spectrum β-lactamase ctx-m, per and ver producing Escherichia coli isolated from raw dairy samples. For this purpose, E. coli were isolated from 247 raw dairy samples (milk and cheese) in Yasooj in 2015-2017, and the isolates were screened for antibiotic resistance, extended spectrum β-lactamase and the presence of ctx-m, per and ver. In total, 200 isolates were selected. The highest frequency of resistance in isolates was against tetracycline (96.5%) and ampicillin (95.5%) antibiotics and the lowest against imipenem (12.5%), In addition, multidrug resistance against four or more antibiotics was observed in some isolates. Extended spectrum β-lactamase resistance was detected in 86 isolates (43%) and ctx-m, per and ver genes were detected in 82, 0 and 7 E. coli isolates, respectively. These findings demonstrated that raw dairy products may be reservoirs for the dissemination of β-lactam antibiotics and that resistance genes could be transmitted to humans through the food chain.
Ali Bahrami, Bita Jenabzadeh, Hamid Mosmeri, Mohammad Davoud Ghafari,
Volume 7, Issue 1 (4-2020)
Abstract
Phenazine 1-corboxylic acid (PCA) is an antibiotic, which inhibits the growth of a vast number of micro-organisms. PCA has has been applied in fields such as pharmaceutical, agricultural, marine and chemical industries. In this study, the antibiotic properties of PCA (produced by pseudomonas aeruginosa MUT.3, which is kept at the Microbial Collection of Malek Ashtar University of Technology) was studied. The impacts of temperature and light conditions on the activity of PCA was investigated within a 230-day period. To investigate the rate of PCA destruction in the experiment, high performance liquid chromatography (HPLC) was utilized. Moreover, the antibacterial activity of PCA under various conditions was studied by minimum inhibitory (MIC) and minimum biocidal concentration (MBC) methods against E. coli DH5α. The results showed that PCA could be active up to 210 days in darkness (at 25oC). Meanwhile, the antibacterial activity of PCA was reduced to 100 and 50 days by increasing the temperature to 35 and 45oC, respectively. In addition, PCA could be active up to 120 and 10 days in visible and ultraviolet light condition, respectively. The MIC and MBC data were consistent with the HPLC results. Detailed data on the activity and stability of phenazine 1-corboxylic acid under various environmental conditions, as presented in this study, could be helpful in industries and healthcare services.
Maryam Haddadi, Gholam Reza Ghezelbash,
Volume 7, Issue 1 (4-2020)
Abstract
Urease-producing bacteria can precipitate calcite nano-crystals by producing urease in the presence of urea and calcium. Calcite precipitation resulting from microbial activity is a process which causes cementation of soil particles in nature. The purpose of this study was to isolate urease-producing halophilic bacteria in order to precipitate calcite in saline soil. Natural samples, including soil and saline waters, were selected for this purpose. At First, halophilic bacteria were isolated by salt-containing TSB medium. Then, a selective medium containing phenol red and urea facilitated the isolation of urease-producing bacteria. Hydrolysis of urea by urease causes alkalization of the medium and the formation of pink halo around colonies. Finally, the best isolate was selected for further study by measuring the release of ammonium by the Nessler method. The ability or inability of isolates to produce calcite was investigated by culturing the isolates on sedimentary medium with different salt concentrations for 10 days. In total, 110 halophilic isolates were isolated, among which 58 isolates had the ability of urease production. The microscopic studies of colonies showed that only 6 isolates were able to produce crystals on precipitation medium. Isolate 6 was selected for further study and then analyzed by X-ray diffraction crystals on precipitation medium. Isolate 6 was selected for further study and then analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM) equipped with an energy dispersive X-ray (EDX) detector. Studies of urease activity showed that this strain released 20.86 mM ammonium after 18 hours. This bacterium was identified by biochemical and molecular analyses and the comparison of its 16S rRNA gene sequence showed 99.92% similarity with the similar gene sequence in Staphylococcus xylosus and then this sequence was submitted in NCBI database with the accession number MG655155. This isolate was able to produce calcite in free salt medium, with salinity up to 10%. Nowadays, many efforts have been made to produce environmental-friendly cements, and therefore, the use of urease-producing halophilic bacteria is an appropriate candidate for bio-cementing in saline environments.
Sogol Tavanaeian, Javad Hamedi, Setareh Haghighat,
Volume 7, Issue 1 (4-2020)
Abstract
Exopolymers (EPS) are high-molecular-weight polymers secreted by some micro-organisms and have several applications in food, pharmaceutical, packaging and agricultural industries, as well as medicine. Actinobacteria are valuable bacteria in biotechnology and many commercial drugs such as antibiotics, antioxidants and immune-suppressant agents are derived from Actinobacteria. Recently, their other capabilities such as exopolymer production have been taken into consideration. Due to the high potential of actinobacteria in producing various compounds and increased prevalence of infections by antibiotic-resistant pathogens, the aim of the present study was to evaluate the potential of isolated Actinobacteria from various locations of Iran to produce EPS with antimicrobial activity. Appropriate dilutions of the samples were, therefore, cultured in ISP2 medium after treatment. The isolates were primarily identified by morphological tests. Then, their ability to produce EPS was investigated in BHI medium with 5% sucrose. The exopolymers of the most efficient strain were analyzed by UV-visible spectroscopy and FT-IR. Finally, the most efficient isolate was molecularly identified. Of the 120 isolates, 38 were able to produce EPS, and six had significant capability of producing EPS (10-14 g/L) and showed antibiotic activity against Staphylococcus aureus, Bacillus subtilis and Aspergillus niger. The EPS of the strain So49 had high absorbance in 190-230 nm, but did not have absorbance in 260-280 nm. Therefore, it does not have any protein impurity. The EPS has hydroxyl and carboxyl functional groups, according to FT-IR analysis. 16S rRNA gene analysis showed that the most efficient isolate had 99.68% similarity to Promicromonospora xylanilytica.
Ehsan Azin, Hamid Moghimi,
Volume 7, Issue 3 (11-2020)
Abstract
The extensive application of dyes in the textile industries and their discharge in the wastewaters leads to numerous environmental pollutions; therefore, treating these wastewaters by efficient and eco-friendly methods is a necessity. In this study, potent strains were isolated by the enrichment technique according to their maximum dye sorption at the lowest possible time at 500nm. Consequently, the best isolate was selected and the dye removal was investigated in different concentrations of Congo red. Therefore, 50 different fungal strains were isolated in this study, of which 10 were able to dye removal. According to the results, isolate ADH8 was selected as the best strain with 94% of dye sorption. Moreover, during 48 hours, 80% of dye content was removed at all dye concentrations by this isolate, and the most growth rate and dye removal was achieved at 1000 mg/l. The results showed that different salt concentrations have no effect on dye sorption of the selected isolate. Molecular identification of ADH8 revealed that this isolate have a 100% similarity to Mucor circinelloides which was deposited under the accession number of UTMC5032 in the University of Tehran Microorganisms Collection. The results obtained from the dye removal of textile wastewater showed that the most amount of dye sorption by M. circinelloides UTMC5032 was 35-60% during three hours of biomass treatment as compared with the control sample. The obtained results indicated that, M. circinelloides UTMC5032 is highly capable in azo dyes sorption and could be utilized in the biosorption of dye in the textile industries wastewaters for the first time.
Bijan Esmaeilnejad, Jamal Gharekhani, Awat Samiei, Hadi Rezaei,
Volume 7, Issue 3 (11-2020)
Abstract
Q fever is caused by Coxiella burnetii and is transmitted by more than 40 tick species. This study aimed to identify the tick species in goats of Meshkin-Shahr, Ardabil Province, Iran, and their role in the transmission of C. burnetii. A number of 365 goats were inspected for the infestation of hard ticks in a randomized sampling design, during a 1-year period from April 2013 to April 2014. A total number of 280 tick specimens were collected and identified and were then examined by molecular methods for the presence of C. burnetii infection. 40.8% of the infected animals had at least one species of tick. The goats which were studied were found to be infested by the following tick species: Hyalomma anatolicum anatolicum (33.9%), Rhipicephalus sanguineus (22.1%), Rhipicephalus turanicus (17.1%), Hyalomma excavatum (11.1%), Rhipicephalus bursa (5%), Hyalomma detritum (3.9%), Hyalomma dromedarii (3.6%), Hyalomma asiaticum asiaticum (1.8%), and Hyalomma marginatum (1%). There were no significant differences between the infestation rate in different seasons, genders and ages of the animals which were studied (p=0.05). The molecular assay of 280 tick specimens revealed the presence of C. burnetii infection in 5 out of 40 pool samples (6-8 tick individuals of the same species in each pool), including H. anatolicum anatolicum (3 pools), H. excavatum (1 pool) and R. sanguineus (1 pool). The present study, therefore, reports the rate of C. burnetii infection transmitted by hard ticks in North-West of Iran for the first time. According to the zoonotic aspect of Q fever, further studies on the carriers as well as other hosts of the infection were found to be necessary.
Mehrdad Ghiasvand, Ali Makhdoumi, Maryam Moghaddam Matin, Jamil Vaezi,
Volume 8, Issue 2 (7-2021)
Abstract
Regarding the rising rate of esophageal cancer in some parts of Asia, including northern and northeastern regions of Iran, the identification of new anti-cancer compounds is essential to combat the disease. The relation between some plants metabolites and these endophytic microorganisms are well characterized. In the current study, the potentials of Ephedra endophyte bacteria for the inhibition of esophageal cancer cell line (KYSE-30) proliferation were investigated. A total of 54 endophyte bacteria (out of 70) were obtained from the sterilized surfaces of two medicinal plants, i.e., Ephedra intermedia and Ephedra foliata. Bacterial strains were then cultured in Tryptic soy broth (TSB) medium and, after 72 h incubation, the produced secondary metabolites were extracted by chloroform. Anticancer effects of secondary metabolites from theses bacteria on esophageal cancer cell line KYSE-30 were evaluated after 24, 48 and 72 h by MTT method. MTT assay results showed that only strain A1 had a cytotoxic effect on KYSE-30 cells. The IC50 amounts of this strain against KYSE-30 cell lines were equaled (µg/ml) to 346.4, 192.8 and 121.3 after 24, 48, and 72 hours, respectively. The molecular identification of strain A1 revealed that Microbacterium maritypicum (99.8% similarity) was the closest identified taxon to the strain studied. According to the promising ability of strain A1 to inhibit the growth of KYSE-30 cell line, the use of natural compounds produced by this bacterium to treat esophageal cancer was found to be applicable. However, more experiments are needed to confirm these results after purifying the ingredients, as well as conducting studies in animal cancer models.
Vida Tafakori,
Volume 8, Issue 4 (1-2022)
Abstract
The purpose of this study was to evaluate phytochemical characterizations and the in vitro antifungal capacity of the aqueous and methanolic extracts of the flower of Tulipa biflora Pall., against various yeast and mold species. For this purpose, fresh flowers were grinded and then macerated in methanol and water overnight, the resulted extracts were then evaluated by various tests. The results indicated that the extracts had different phytochemical components such as terpenoids, tannins, flavonoids, alkaloids, phenols, and phlobatannins. After the evaporation of solvents, antifungal activities of the concentrated extracts were evaluated by the well-diffusion method on Candida albicans, Trichosporon asahii, Yarrowia lipolytica, Aspergilus niger and Fusarium oxysporum. The results showed that the extracts were effective on yeasts and mold species studied except for Aspergilus niger. In order to determine the minimum inhibitory concentration (MIC) and minimum biocidal concentration (MBC) of the extracts, anti-microbial tests were performed in micro-plates. The methanolic extract had more antifungal effectsthan that in the aqueous extract. Therefore, the extract of Tulipa biflora could be introduced as a source for antifungal agents.
Hiba Zedan, Seyed Masoud Hosseini, Ali Mohammadi,
Volume 9, Issue 1 (3-2022)
Abstract
The aim of this study was to increase the shelf life of traditional yogurt, to improve its consistency and to prevent whey syneresis by adding tarragon essential oil. Yogurt was produced by industrial procedures and then the essential oil was inoculated into yogurt in different concentrations (10, 25, 30 ppm). Samples were examined for water storage capacity and microbial evaluation during 3 weeks of storage at two temperatures (refrigerator temperature and room temperature). The results showed that different concentrations of tarragon, temperature and storage time had a significant effect (p <0.05) on water holding capacity as well as the number of starter bacteria, molds, and yeasts. Tarragon essential oil reduced the number of bacteria, molds, and yeasts that spoil yogurt. The final results showed that the use of tarragon was not effective in water retention of yogurt samples, but it affected the number of initiator bacteria and yeast. Yogurt samples with high concentration of tarragon had the highest score in terms of consistency and sour taste. While samples with low concentration of tarragon, in terms of yogurt taste, had the highest sensory score.
Atefeh Shahraki, Mrs Maryam Mohammadi-Sichani, Mrs Monireh Ranjbar,
Volume 9, Issue 3 (12-2022)
Abstract
Rhizospheric bacteria are among the beneficial soil microorganisms that improve plant growth. These bacteria increase plant growth through various mechanisms such as the production of various phytohormones and the ability to solubilize phosphate. The aim of this study was to investigate the effects of rhizosphere bacteria on the growth of Carthamus tinctorius to improve its physiological and biochemical indicators. Carthamus tinctorius seeds were inoculated with five isolates of rhizosphere bacteria and were then planted the seeds in pots. Subsequently, the physiological and biochemical parameters of the plants, including the rates of auxin production, phosphate dissolving, photosynthetic pigments and the contents of proline and malondialdehyde were measured. For this purpose, a factorial experiment were conducted using a completely randomized design with three replications. The ANOVA was performed and a comparison of the means was carried out using Duncan’s multiple range test. The results indicated that the largest stem fresh weight, root fresh and dry weights observed in the treatments of using Pseudomonas fluorescens (auxin concentration of 23.55 μg/mL) and Bacillus muralis (auxin concentration of 22.27 μg/mL). In addition, all bacterial species increased the safflower seed germination rate compared to the control group. The largest malondialdehyde content was recorded in the treatment with Bacillus albus, and MDA content decreased in the treatments that produced larger amounts of auxin. In general, the finding of this research suggested that bacterial inoculation was capable to significantly affect the growth of safflower and improve its qualitative and quantitative growth parameters.
Ensieh Salehghamari,
Volume 9, Issue 3 (12-2022)
Abstract
Saline rhizospheric areas are untouched environments for isolating actinomycetes with the potential of valuable salt tolerant enzyme production. In this study, we isolated and evaluated a total number of of 26 actinomycete strains from plant rhizosphere of the periphery of Dasht-e-Kavir desert. Isolated actinomycetes produced different enzymes. Among them 50, 46, 39, 27, 10 and 7 % of the isolates produced amylase, lipase, protease, gelatinase, lecithinase and urease, respectively. The most frequently produced enzymes among the isolates were amylase, lipase and protease. Combined hydrolytic activity was also detected in some actinomycete strains. Among the isolates, strains Q1, Q4 and Q11 with the most diverse enzymes production, were identified and their 16s rRNA analysis showed that they are mostly similar to the Streptomyces scopiformis, Streptomyces argenteolus and Streptomyces manipurensis, respectively. Finally, due to the enzymatic diversity obtained and the valubility of the halophilic bacterial enzymes in industry, it seems that actinomycetes isolated from this saline habitat are potentially suitable for biotechnological applications.
Mehri Farzadi, Reza Khakvar, Abolghasem Mohammadi, Thomas Rattai,
Volume 9, Issue 4 (3-2023)
Abstract
Urmia Lake is the largest lake in the Iranian plateau and the second largest Salt Lake in the world. This study was conducted to identify hypersaline bacteria in the lake through the screening with molecular markers. For the molecular study of the bacterial microbiome of the lake, samples were collected from water, sludge and soil of the different parts of the lake during different seasons of 2018 and 2019, and then transferred to the laboratory under standard conditions. Bacterial isolates were purified from the samples using universal culture media. ERIC molecular marker was used to study the species diversity. After clustering analysis of the species on the basis of their genetic markers, one bacterium from each cluster was selected as the representative of each cluster and then identified by DNA barcoding method using the 16srDNA. Biochemical tests were performed to confirm the molecular results. In total, 102 bacterial isolates were isolated and purified from the samples, of which only 29 isolates were extremely-halophilic. The molecular diversity of isolates, based on ERIC molecular marker, showed that isolates can be assigned to five different clusters. Five isolates selected from each cluster were selected and their 16SrDNA region were amplified and sequenced with 16SrDNA-specific primers. The results showed that the five selected isolates with 99% similarity belonged to the species Microbulbifer halophilus, Halomonas salina, Bacillus sonorensis, Salinivibrio costicola and Bacillus aquimaris. The results of molecular identification were consistent with the results of biochemical tests.
Fereshteh Mohamadhasani Javar, Mehdi Rahimi,
Volume 10, Issue 2 (9-2023)
Abstract
Heavy metal contamination (HMs) of water and soil is the most serious problem caused by industrial and mining processes and other human activities. Mycoremediation is a biotechnological method that employs fungi to remove toxic contaminants from the environment in an efficient and cost-effective manner. Pleurotus species are considered to be the most popular and widely cultivated species worldwide, and this may be due to their low production cost and high yield. It has been indicated that Pleurotus species may improve plant growth in metal-contaminated soils through enhancing nutrition uptake or by alleviating toxicity of the metals. In this experiment, the fungus was grown in vitro in liquid and solid media for 3 weeks on five different concentrations (0, 15, 30, 45, 60 ppm) of five heavy metals (Cd, Zn, Ni, Pb, Mn) as sulphate and the effect of these metal on radial growth, biomass production and metal content of fungal biomass were determined. Based on the results, this fungus showed a great variety of tolerance against the metals, as that growth parameters were increased in the case of two metals contamination (Zn and Mn) and inhibition of growth was observed even at the low concentrations of nickel, cadmium and lead (15 mg/liter). The amount of metal accumulation in the fungal mycelium also increased with the increase of the metal concentration in the culture medium. In this research, for the first time, the growth parameters and the amount of accumulation of heavy metals in axenic conditions have been investigated and described.
