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The aim of this study was to isolate and identify a-amylase-producing bacteria present in mangrove ecosystems on Qeshm Island, Hormozgan, Iran. Samples of mangrove leaves and roots were screened for a-amylase activity using Lugol’s solution. Crude extracts were prepared of positive samples, and their a-amylase activity was determined by the Bernfeld method. The two strains with the highest activity were identified by molecular analysis of their 16S rRNA genes. a-Amylase production and activity were optimized by varying temperature and pH. 46 bacterial strains were isolated from mangrove tree leaf and root samples. Of these, 28 strains were capable of producing a-amylase. 16S rRNA gene sequence analysis of two strains with the highest enzyme production identified them as Bacillus sp. strain HR10 and Bacillus sp. strain HR11. The optimum temperature for enzyme production was 35 and 30 °C for strains HR10 and HR11, respectively, and the optimum pH was pH 8 for both strains. The highest enzyme activity was observed at 70 °C and 60 °C for the HR10 and HR11 strains, respectively, and the optimum pH was pH 8 for both strains. In conclusion, we have shown that bacteria isolated from mangrove leaf and root samples are potential source of a-amylases, tolerating a wide range of temperature and pH. Such a-amylases may be of interest for use in environmentally friendly industries.

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  Probiotics are live microorganisms which when consumed in adequate amounts, can have a beneficial effect on the host. Lactic acid bacteria are the most common type that have been introduced as probiotics and are present in dairy products. The aim of this study was to isolate and identify the probiotics from microbial flora of cow milk and its traditional yogurt in Khoi area. To achieve this goal, the lactic acid bacteria were isolated by phenotypic methods (cellular morphology, colony pigmentation, Gram staining, catalase test, biochemical tests including growth in different temperatures 10°C, 15 °C and 45 °C, various concentrations 4 % and 6.5 % of salts and fermentation of 17 types of sugar) and their probiotic potential (resistant to stomach acid and bile salts) were evaluated. Then, to identify more accurately, the 16S rRNA gene of Lactobacilli were replicated with pairs of specific primers and then the purified PCR product was sent for gene sequencing. At the end, 14 strains of Lactobacilli were reported as the natural microbial flora with probiotic potential in Khoi area. These bacteria provide the good quality of the dairy products in those areas and can be used as the starter culture in industrial manufacture of dairy products.  

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In a marine environment, the biofilm formed on the submerged surfaces leads to fouling of larger organisms. This leads to many environmental and economic problems for the marine industries. Due to the harmful effects of chemical antifouling, the development of environmentally friendly anti-biofilm strategies can be an important step to control fouling.
Therefore, the present study was performed with the aim of isolation of biofilm-forming bacteria from Persian Gulf waters and investigating the antimicrobial effect of thymol against selected bacteria.82 bacterial were isolated and their ability to form biofilm was measured. Among these, 5 isolates were selected and identified using 16S rRNA sequences. The results showed that the 5 selected isolates belonged to the Proteobacteria (genus Vibrio, Kangiella and Psudoaltromonas). In the study of the antibacterial effect of thymol, K. spongicola (PH1) showed the highest sensitivity in disk diffusion method (with a growth inhibition zone diameter of 18 ± 0.57 mm). The minimum inhibitory concentration and minimum bactericidal concentration (at 31.5 and 62.5 μg /ml, respectively) were obtained against the same bacterium. The inhibitory thymol on biofilm formation and performed biofilm by Psudoaltromonas sp. (PH18) showed that thymol at concentrations sub-MIC is able to inhibit biofilm formation. The effect of thymol on the performed biofilm at concentrations higher than MIC is noticeable. Based on the results, due to the anti-biofilm activity of thymol against marine bacteria, its use as a natural compound in antifouling coatings can be suggested.

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  The aim of this work was identified lactic floraas a traditional fermented food and then evaluates antimicrobial activities of some strains. A total of 140 Gram-positive and catalase-negative isolates were subjected to grouping by physiological and biochemical tests and carbohydrates fermentation. Based on the resultsthese 140 isolateswere dividedinto 9 groups. Two or three isolated were selected from each group and 16S rRNA was amplified using universal primers. Diversity of lactic acid bacteria in horreh was as followings:Lactobacillus fermentum (30.00%),Lactobacillus plantarum (28.57%), Lactobacillus brevis (15.00%), Weissellacibaria(8.57%),Enterococcus (faecium and faecalis) (7.14 %), Leuconostoc (citreumand mesenteroides subsp.Mesenteroides) (6.42%) and Pediococcus pentosaceus (4.28%). Antagonistic activity of 20 isolates (strains) of lactic acid bacteriaobtained fromhorreh was evaluated against food- borne bacteria. Sixteen isolates in Agar spot method and 14 isolates in well diffusion assayshowed antibacterial activity against at least one of these indicators. Eight isolates including:Ent. faecium (1), Ent. faecalis (1), P. pentosaceus(1) and Lb. plantarum (2) exhibited  the  highest  antagonistic  activity toward Listeria innocoa. Antagonistic activity of cell free supernatant (CFS) from Lb. plantarum showed the highest thermal stability. Also, two isolates belonging to:Ent. faecium, Ent. Faecalis presented antibacterial activity at pH=7. Only, the supernatant of Lb. plantarum was not influenced by proteinase K.The results showed that the supernatant of some isolatestestedcan be used as a bio preservative in food products.

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Kimchi is a general term for fermented vegetables.The aim of this study was to isolate and identify the Lactic Acid Bacteria involved in spontaneous fermentation of this product used biochemical and molecular methods. In this study, after successive culture on specific media, in order to classify of 85 selected isolates that according to preliminary experiments seemed Lactic Acid Bacteria, physiological and biochemical tests were done and then fermentation of 10 different carbohydrates were performed. Based on these tests, 85 isolates were divided into 10 groups. Some isolates were selected from each group and 16S rRNA was amplified using universal primers. Diversity of lactic acid bacteria in Kimichi was as followings: Lactobacillus plantarum (41.17%), Lactobacillus fermentum (9.41%), Enterococcus faecalis (3.52%), Enterococcus faecium (7.06%), Leuconostoc citreum (2.35%), Leuconostoc mesenteroides (3.52%), Pediococcus pentosaceus (8.23%), Wisella cibaria (24.70%). This fermented product has a wide microbial diversity which originates from natural microbiota presented in the raw vegetable. Lactic acid bacteria can produce a variety of acids and enzymes which play an important role in development of unique flavor and tasteTherefore, this strains that isolated from Kimchi can be used in the food industry.

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Fermentation is used for centuries to protect quality improvements or flavor modifications of cereals, fruits, vegetables, milk and meat. Yellow Zabol kashk (Sistani) is a grain-dairy fermented product, which is highly consumed in Sistan-Baluchistan province. The aim of this study was to isolate and identify the Lactic Acid Bacteria involved in spontaneous fermentation of this product to introduce the native strains. These strains could be used in industry or some of them may be considered as probiotic strains. The cell morphology of each strain was investigated. Then gram-positive and catalase-negative isolates were selected. In order to classify 83 selected isolates that seemed Lactic Acid Bacteria according to preliminary experiments, physiological and biochemical tests, including growth at 10°C and 45°C, 6.5%  NaCl, pH=4.4 and pH=9.6, carbon dioxide production from Glucose and carbohydrates fermentation were performed. Twenty eight selected isolate identified genotypically based on 16S rRNA gene sequencing. The results showed that the isolates belong to: Lactobacillus plantarum (24.09 %), Lactobacillus helveticus (13.25 %), Lactobacillus brevis (963 %), Lactobacillus delbrueckii (18.07 %), Lactococcus lactis (13.25 %), Leuconostoc mesenteroides (9.63 %), Leuconostoc citreum (2.40 %) and Pediococcus pentosaceus (9.63 %). To identify the bacteria, especially lactic acid bacteria it is suggested using both culture and molecular-based method.

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Bio-inoculants have potential role in plant growth promotion. The present study evaluated the potential of Pseudomonas strains as bio-inoculants in wheat on the basis of plant growth promotion and physiological characterization. The 16S rRNA gene sequencing and phylogenetic analysis revealed that four isolated strains belonged to genus Pseudomonas. These strains were positive for phosphorus solubilization and indole acetic acid production, whereas only two strains were positive candidate for their nitrogen fixing ability as determined by presence or absence of nifH gene through amplification from polymerase chain reaction. The pot experiment showed that the integrated use of Pseudomonas strains as co-inoculant and 50% applied mineral fertilizers enhanced the maximum wheat growth and development from 58 to 140% for different shoot and root growth parameters. The strain NCCP-45 and NCCP-237 were closely related to Pseudomonas beteli and Pseudomonas lini, respectively. These isolated strains can be used to increase crop productivity by using as a bio-fertilizer inoculum.

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Phenotypic and genotypic diversity as well as symbiotic effectiveness of twenty one symbionts isolated from nodules of four Acacia species (Acacia melanoxylon, A. mearnsii, A. saligna and Acacia tortillis) grown in Morocco were evaluated. Growth in various media (YMA, YMA-BBT, YMA-RC), colony morphology, tolerance to stress factors (temperature, pH, salt concentrations, various heavy metals) and different carbon sources were used as phenotypic markers. The genetic characterization was studied by Random Amplification of Polymorphic DNA (RAPD) and 16S rRNA gene sequencing. The symbiotic effectiveness of rhizobial isolates on acacia was evaluated using plant nodulation assay in controlled conditions. Results showed that twelve isolates were fast growing, all of the twenty one isolates tolerated pH between 4.8 and 8.8 and temperatures of 14, 22, 28, and 37°C, while only five could grow at 44°C and three at 55°C. Highest resistance to heavy metals was recorded for arsenate, mercury, chromium; in contrast, low resistance was noted for copper (15 isolates resisted to10 mg mL^-1). Most of the isolates were able to grow in a wide range of carbohydrates. The genotypic analysis of the tested isolates showed that they could be regrouped into three principal clusters based on their RAPD profiles. Acacia saligna was principally nodulated by Bradyrhizobium sp. while the other species were nodulated by different rhizobial species. Both phenotypic and genotypic studies showed great rhizobial isolate’s diversity. The symbiotic effectiveness tests showed that two isolates (AsF and AsAg₁) had high N₂ fixing potential on Acacia saligna.

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Lactobacilli are the most well-known strains with probiotic properties that have a great effect on promoting gastrointestinal health. The purpose of this study was to isolate and evaluate the probiotic properties of local Lactobacillus in dairy products in Fars province. Gram-positive and catalase-negative bacilli were isolated and analyzed from dairy samples by chemical methods. To evaluate the probiotic properties of the isolates, their growth rate was measured at different acidic and alkaline pHs, different concentrations of bile salt and NaCl salt. The antimicrobial activity of the isolates on pathogenic bacteria was investigated by agar well diffusion method and also susceptibility testing to common antibiotics was performed by disk diffusion method. Optimal strains were identified molecularly by 16 S rRNA gene sequencing. Out of 36 gram-positive and catalase-negative strains, 10 strains were biochemically similar to Lactobacilli that 5 strains being able to grow at pH 3 to 9 and different concentrations of bile salt and NaCl salt. These bacteria had antimicrobial activity against common pathogens and were resistant to the antibiotics Clindamycin, Ampicillin, Erythromycin, and Tetracycline. Strains M3 and Y4 had better probiotic properties. Molecular evaluation showed that these two strains are 100% and 99.98% similar to Lactobacillus brevis and Lactobacillus casei strains, respectively. As a result, it was found that these two strains of Lactobacillus with approved probiotic properties are available in traditional dairy products in Fars province, which can be used in the dairy food industry to improve the quality of livestock and poultry feed.

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