فهرست مطالب

  • Volume:3 Issue: 1, Winter-Spring 2020
  • تاریخ انتشار: 1400/12/14
  • تعداد عناوین: 6
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  • Monire Abolhasani Sooraki, Vahid Poozesh *, Fatemeh Salimi, AhmadReza Mehrabian Pages 1-18

    Phytoremediation is an eco-friendly technique for hydrocarbon bioremoval. Phytoremediation efficiency can be enhanced by cooperation of plants and crude oil degrading bacteria. This study was aimed to select crude oil tolerant grasses and clarify the bioremoval efficiency of R.ruber KE1-augmented phytoremediation. For this purpose, Resistance of Festuca rubra rubra, Festuca rubra commutate, Lolium perenne and Poa pratensis to crude oil was evaluated. Further, supportive and augmenting role of R.ruber KE1 treatment on morphological and biochemical properties of grasses and crude oil phytoremediation was assessed. According to the results Festuca rubra rubra, L. perenne were selected as more crude oil resistant grasses. R.ruber KE1 could significantly enhance their growth parameters (radicle, root and shoot length) in the presence of crude oil. The most applied concentration of crude oil (5% w/w) inhibited Festuca rubra rubra growth while R.ruber KE1 treatment improved Festuca rubra rubra growth (p <0.05). Combination of R. ruber KE1 with L. perenne or Festuca rubra rubra resulted in higher degradation rate of >70% in all applied concentration of crude oil after 40 days. R. ruber KE1 treatment enhanced biodegrading of insoluble (36%→1.82%) and soluble (53.86%→14.52%) compounds of crude oil. R.ruber KE1-augmented phytoremediation can be promising approach to degrade recalcitrant hydrocarbon pollutants and remediate contaminated soils.

    Keywords: Bioremediation, Crude oil, Festuca rubra rubra, Lolium perenne, R.ruber KE1
  • Mostafa Alamholo * Pages 19-27
    The evolution of bacterial strains with greater resistance to conventional antibiotics has led to the use of new generations of antibiotics. This research aimed to investigate the antiradical and antibacterial properties of a methanol extract from the aerial and underground parts and seeds of Echium altissimum (Syn. Echium italicum) on pathogenic bacteria. The samples (i.e., aerial and underground parts and seeds) of E. altissimum were collected from Urmia, Iran. The antibacterial properties were analyzed by agar well diffusion assay. In addition, the minimum inhibitory and bactericidal concentrations were measured by the serial dilution method. However, the phenolic and flavonoid contents were obtained by the Folin-Ciocalteu and Aluminum chloride methods, respectively. Furthermore, free radical scavenging activity was measured by 2, 2-diphenyl-1-picrylhydrazyl. The most susceptible was obtained for Micrococcus luteus on the seed methanol extract of E. altissimum. Next, the IC50 of the aerial and underground parts and seeds were determined as 0.1054, 0.1278, and 0.1508 mg mL-1, respectively. The methanol extract of seed exhibited a MIC of 0.75 mg mL-1 against M. luteus. Lastly, the highest phenol and flavonoid contents were determined as 246.12 (mgGA/g) and 6.29 (mgQ/g) from the seed methanol extract. The major compounds were determined to be rosmarinic acid (28.36%) and myricitrin (12.38%). In general, E. altissimum exhibited antibacterial and antioxidant activity and is therefore suggested for producing natural antibiotics and rare drugs, especially anti-infective drugs for the pharmaceutical science.
    Keywords: Echium italicum, Secondary metabolites, Human pathogenic bacteria, Phytochemical, Antioxidant
  • Atefeh Salehibakhtiyari, Zahra Etemadifar, Matia Sadat Borhani * Pages 29-39
    The application of carotenoids in the pharmaceutical industry has received great attention in recent years. In this regard, extremophile microorganisms, such as Deinococcus radiodurans R1 (ATCC 13939), have shown to be a promising source of carotenoids. However, there is no previous study concerning the effect of tricarboxylic acid cycle intermediates on the carotenoid biosynthesis of this bacterium. In the present study, the influence of process parameters (citrate, malate, succinate, glutamate, and pH) on the carotenoid production of D. radiodurans R1 was evaluated using the response surface methodology. A total of 32 experiments at five levels for each factor were analyzed using the Design Expert 7 software. According to the results, the response surface methodology was a robust optimization method to enhance the production of carotenoid by D. radiodurans R1 (52.3 mg/L) as much as 21.8-fold more than the unoptimized conditions (2.4 mg/L). For the studied strain, the optimum cultural condition for carotenoid biosynthesis was observed in the fermentation medium (pH 7) containing citrate (10mM), malate (15mM), succinate (10mM), and glutamate (10 mM). Overall, the results of this study revealed that the microbial biomass and carotenoid production were affected by malate more significantly than the other studied tricarboxylic acid cycle intermediates.
    Keywords: Carotenoid, Deinococcus radiodurans R1, Optimization, Response surface methodology
  • Zahra Sadeghabady, Monir Doudi *, Ladan Rahimzadeh Torabi Pages 41-52
    The influent of toxic heavy metals into aquatic environments has greatly increased and is considered a serious hazard for living organisms. In recent years, several technologies have been developed with the aim of reducing or removing heavy metals from the contaminated environment. Among these, technology developed based on microorganisms is more advantageous than other methods. In the present study, metal resistant bacteria (MRB) and antibiotic resistant bacteria (ARB) were first isolated from the sewage treatment plant of Ahvaz, Iran. Sampling was carried out from sewage. Then, biological oxygen demand (BOD), chemical oxygen demand (COD), pH, and concentration of heavy metals were detected in the samples by ICP-AES. Metal resistant bacteria were isolated by the agar diffusion method on lead (Pb) and cadmium (Cd) in a PHG II medium. The isolates were molecularly identified by genome sequencing. Next, the antibiotic resistant pattern of the potent metal resistant isolates (MIC > 1 mg/mL) was determined. Results showed that Pb and Cd concentrations in the sewage samples were above global standards (0.3 and 0.04 mg/mL, respectively). Bacillus cereus and Salmonella enterica subsp. enterica serovar typhi were found to be the most potent Pb resistant isolates (MIC = 5.5 mg/mL, MBC = 6 mg/mL on both isolates). The MIC and MBC on Bacillus cereus were 3.0 and 3.5 mg/mL, and the MIC and MBC on Salmonella enterica serovar typhi were 4.0 and 4.5 mg/mL, respectively. The isolated Bacillus cereus also showed high resistance to cefixime and penicillin.
    Keywords: Sewage, 16S rDNA sequencing, Heavy metals resistance, Lead, cadmium, Antibiotic resistant bacteria, Bacillus cereus, Salmonella enterica
  • Vahideh Montazeri, Gholamreza Yasaei, Mohammadjavad Kazemi Pages 53-62

    The genus Lactobacillus contains several Gram-positive bacteria that are microaerophilic or facultatively anaerobic. These are the main groups of lactic acid bacteria. Some lactobacilli are used in the production of yogurt, cheese, and other fermented products. The purpose of this study was to isolate, identify, and characterize the technological characteristics of lactic acid isolated from a single-humped camel in the city of Tabas, Iran,by standard technological properties tests. From a total of 12 raw milk samples, 60 isolates were investigated by morphological and Gram studies. Thirty-six isolates of catalase-negative and Gram-positive selected for genus identification were compared using the Bergey Book. All examined isolates were analyzed to determine the carbohydrate fermentation pattern and CO2 production. The results showed that 23 isolates of Lactobacillus (with a 63.88% frequency) were found in five groups, including Lactobacillus gasseri isolates (L1-L7), Lactobacillus gallotix isolates (L8-L13), Lactobacillus xiangfangensis isolates (L14-L16), Lactobacillus salivarius isolates (L17-L21), and Lactobacillus paracasei isolates (L22, L23). Additionally, five Pediococcus isolates, P1-P5 (13.99%), and eight Enterococcus isolates, E1-E8 (2.22%), were obtained. Seven isolates were evaluated for molecular identification using 16S rRNA. Finally, five Lactobacillus, one Pediococcus, and one Enterococcus were identified. These seven isolates were examined by complementary tests including proteolytic, lipolytic and autolytic activities, and antibiotic and acid resistance. Two isolates, K030508 (L. salivarius) and K020704 (L. xiangfangensis), exhibited the highest potential for future commercial use as a starter culture.

    Keywords: Lactic acidic bacteria, Single-humped camel, Probiotic, Molecular identification, Acidic condition
  • Behrang Khodaei, Khosrow Rostami, Zahra Esfahani Bolandbalaei Pages 63-73

    Nitrate concentration above standard level if present in drinking water, possibly reduces to nitrite in the human digestive tract. Further converts hemoglobin to metheomoglobin with a great loss in oxygen-carrying capacity, which is responsible for developing metheomoglobina. The nitrite may react with amines forming carcinogenic nitrosamines. The wastewater of a petrochemical was initially treated with microorganism of the municipality of Shahrek-e-Ghareb located in Tehran. A prolonged, poor and irreproducible result was obtained, which was perhaps on the count of higher ratio of heterotrophic bacteria. Further literature experience the procedure as showing that the autotrophic organism synthesis nitrification of certain wastewater at higher rate than heterotrophic bacteria and fungi. The autotrophic bacteria from wastewater of depo 93 of Shiraz petrochemical plant was partially purified by dilution method through 13th generation. The 8th microbial consortium resulted as choice source of isolated bacteria for nitrification of the same wastewater. Hydrochloric acid was used to reduce the original pH of the wastewater which was 10.5 to about neutral range. The medium pH and alkalinity was raised by addition of 2 V/W % sodium carbonate to desirable level, which resulted in considerable ammonia oxidation. The effect of parameters such as feed concentration, inoculum size, initial pH, shaker's speed and temperature on nitrification was examined. It was observed while the medium temperature maintained at about 29 ˚C, shaker speed of 2.5 s-1, pH: 7.8 and inoculum size of 10 % V/V of 8th microbial consortium resulted in approximately 85% using the Watson medium and 80 % petrochemical wastewater nitrification. The data was fit to Monod type of equation and good agreement of 99.68 % was obtained.

    Keywords: Ammonia oxidation, Autotrophic nitrifiers, Nitrification, Nitrite, Nitrate