BIOLOGICAL JOURNAL OF MICROORGANISM
Year:2019 | Volume:7 | Issue:28 |Papers Count:10

Introduction: Oleaginous yeasts could produce lipid with high contents of poly unsaturated fatty acids (PUFA). Isolation of oleaginous species with a strong ability to produce lipid and long-chain polyunsaturated fatty acid (LCPUFA) could be considered as an effective step to the commercialization of LCPUFA production.Materials and methods: Having isolated an oleaginous yeast species from fish, the species were identified by the molecular method. One factor at time and response surface methods was used for optimization of lipid and oleic acid production. Fermentation was being conducted in five days.Results: The yeast specie which isolated from the gills of trout fish was Wickerhamomyces Siamensis SAKSG. Response Surface Methodology (RSM) indicated that optimal conditions for lipid production (27% of dry biomass) was obtained at the middle levels of glucose (42 g/L) and minimum amount of soy bean (5 g/L). The optimal amount of oleic acid (66.5% of lipid) was obtained at high levels of glucose (80 g/L) and soybean (15 g/L). Docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) and arachidonic acid (ARA) were also produced by this new isolated yeast.Discussion and conclusion: Wickerhamomyces SiamensisSAKSG as oleaginous yeast had great ability to produce lipid with a reasonable amount of LCPUFA. Chemical condition of media highly impact on LCPUFA production. More to the point, protein had positive effect to LCPUFA production via stimulation of the yeast growth.

Introduction: The process of calcite precipitation resulted from metabolic activities by microorganisms is biocalcification. In this process, calcite (CaCO3) is deposited on the soil grains by metabolic activities of microorganisms resulting in increased stiffness/strength and reduced erodibility of soil.Materials and methods: In this study, urea hydrolysis and calcite precipitation rates in soil stabilization process were evaluated by the bacterium Bacillus sp. HAI4 through Taguchi method. Also, it was designed a wind tunnel for analysis of soil stabilization rate.Results: In this investigation, three factors (NH4Cl, urea and molasses) were surveyed in optimization of soil stabilization .Results of this study illustrated that Taguchi method is one of effective methods for optimization of effective factors in soil stabilization process. In this case, urea concentration had higher effect on soil stabilization and calcite sedimentation by Bacillus sp. Also, evaluating factors interaction showed relationship of factors together. Three levels (0.5, 1 and 1.5 g/L), were determined for NH4Cl factor in which the highest effect (4.353%) in soil stabilization was related to level 3. Increasing of NH4Cl resulted in high soil stabilization rate. Three levels 20, 30, and 40 g/L of urea were applied. Results illustrated that effective level was 3 with 4.313%. Also, Taguchi design was in this study, as three levels of molasses (30, 40 and 50 gr/L) illustrated maximum soil stabilization in level 2 by 3.873%. In fact, by increasing of molasses, soil stabilization firstly increased and then decreased.Discussion and conclusion: Totally, this study shows two factors (NH4Cl and urea) that have a major effect in urea hydrolysis and calcite precipitation rates.

Introduction: According to the applications of gold nanoparticle in electronic and medicine, green biological synthesis methods for gold nanoparticle synthesis are considered. Different biological methods cause variant types of metal nanoparticles. Enzymes are one of the powerful tools in this approach. In this study, the role of tyrosinase in gold nanoparticle synthesis was studied by spore displayed tyrosinase.Materials and methods: Bacillus subtilis spore displayed tyrosinase developed in our previous work, was used as an enzyme source for synthesis of Au nanoparticles (AuNPs). X-ray diffraction technique and transmission electron microscopy were used to characterize the nanoparticles. To confirm the role of enzyme in AuNPs synthesis, two types of tyrosinases from Bacillus megaterium and Streptomyces also were studied.Results: The results revealed that AuNPs were produced due to reducing Au3+ to Au0 by spore displayed tyrosinase. These biogenic nanoparticles showed mixed structures including spherical, triangular and hexagonal with the approximate size 2.5 to 35 nm. Furthermore, purified Bacillus megaterium tyrosinase and Streptomyces tyrosinase also produced AuNPs.Discussion and conclusion: The supposed mechanism of Au nanoparticle synthesis by tyrosinase, is electron transferring from copper ions to Au3+. The results represent a green environmental friendly simple method in synthesis AuNPs by spore displayed tyrosinase.

Introduction: The organophosphate insecticides such as chlorpyrifos and diazinon have been widely used to control insects in home, agriculture, and veterinary. These compounds are a threat to public health and the environment; on the other hand, they have low degradation rate and therefore can be stable for a long time in soil. A major factor determining the fate of organophosphate insecticides in soil and water is biodegradation.Materials and methods: Two diazinon and chlorpyrifos degrading bacterial strains were isolated from pesticides contaminated soils. The isolated bacterial strains were identified by 16S ribosomal RNA gene and fatty acid methyl ester analysis.Results: Strong correlation was seen between microbial growth and the two organophosphates degradation. On average, bacterial strain 1 and 2 degraded 88.27% and 82.45% of initial applied diazinon in medium and degraded 81.07% and 88.35 % of initial applied chlorpyrifos during 20 days, respectively. The isolated bacterial strains were identified as Acinetobacter and Pseudomonas sp. The highest diazinon degradation were found by Acinetobacter and the highest chlorpyrifos degradation were found by Pseudomonas when cultivated in the mineral salt medium.Discussion and conclusion: The identified pure bacterial strains utilized chlorpyrifos and diazinon as a source of carbon. They were able to degrade most of the parental molecule in 20 days. Therefore, the isolated bacterial strains may have the potential for use in the bioremediation of diazinon and chlorpyrifos-contaminated soils.

Introduction: In this study, the deep-sea bacterium, Idiomarina zobellii, was used as a new source for the production of lipase. Lipases from halophilic bacteria are attractive for use in diverse industrial and biotechnological applications.Materials and methods: The optimal temperature and pH for the activity of I. zobellii lipase was determined using different temperature and pH ranging from 30-60oC and 7-11, respectively. The growth conditions influencing lipase production were determined using two-level fractional factorial Plackett–Burman design. The optimum levels of effective factors for production process were determined by using the response surface central composite design.Results: The optimum temperature and pH of I. zobellii lipase in the crude mixture were 7-8 and 50oC, respectively. Among the screened 10 factors, MgCl2, yeast extract, sodium bicarbonate, ammonium nitrate concentrations and temperature were found to be effectively important. The highest productivity level was achieved at 42oC temperature and MgCl2 7.18 (g/L), yeast extract 1.1 (g/L), NH4NO3 3.65 (g/L) and NaHCO3 0.11 (g/L) concentrations. When the predicted optimum levels of effective factors were employed, the enzyme activity almost doubled (0.8 comparing to 0.39 U/ml) of the initial.Discussion and conclusion: The Idiomarina zobellii originated lipase is an alkalophile enzyme. A significant increase in enzyme production, as large as 2.09 folds, is achievable under optimized conditions that favours biotechnology and industrial applications.

Introduction: Zymoseptoria tritici, is a species of filamentous fungus and causes the widespread wheat disease Septoria tritici blotch (STB). Salicylic acid has a key role in plant defence reactions and is also involved in the induction of systemic acquired resistance. However, the contribution of SA to the interaction of Z. tritici -wheat in STB is not entirely clear. In this study, it was shown that the Z. tritici mycelial growth and conidia germination were significantly inhibited the presence of increasing concentration of SA in both liquid and solid media. In addition, the effect of SA on pathogenicity of Z. tritici in wheat was investigated.Materials and methods: In this study, the inhibitory effect of SA on Z. tritici at different concentrations (1 to 20 mM) in vitro, and also, the efficacy of its exogenous application in the suppression of STB in wheat under the greenhouse condition were investigated. In vitro evaluation was done on YMDA and YMDB to determine the effect of SA on the germination of conidia and growth of mycelium, respectively. Susceptible bread wheat cultivar was grown in pot and inoculated with fungus spores and SA in a three-leaf stage for green house experiments.Results: The results showed that the germination of conidia was completely inhibited by 4 mM SA. Furthermore, in modified YMDA plates at over 0.8 mM, the colonies diameter was reduced significantly. The result of in planta assay indicated that the foliar application of 4 mM SA can significantly reduce the disease symptoms on the wheat leaves.Discussion and conclusion: Regarding our data, it seems that SA shows more inhibitory effect in in vitro experiments than in planta. Moreover, according to the positive effects of SA on STB, the survey results can be considered as a potential approach in the management of this disease.

Introduction: Production of Ganoderic acid (GA) and Exopolysaccharide (EPS) with using beneficial fermentation strategy has received great attention recently. The aim of present study is comparison of GA and EPS production by G. lucidium in submerge, Semi-Solid and Solid-State fermentation.Materials and methods: Potato dextrose Agar (PDA) for cultivation of G. lucidum was used. A modified medium formulation for Semi-Solid-State fermentation was also used with both submerged and Solid-State cultivation advantages. The optimized media components and main effects, such as carbone source, inducers, and aeration were studied with using Taguchi orthogonal array design. Thin Layer Chromatography (TLC) was used to detect GA in mycelium and fruiting body of G. lucidum and Fourier transform infrared (FTIR) spectroscopy was used to detect EPSs in submerged fermentation.Results: Findings showed that the increase of GA in Semi-Solid-State fermentation (256 mg/g) with a combination of wheat bran 9g/L, oak chips 13g/L but without aeration. Findings showed that EPS production in submerged fermentation was more noticeable than Semi-Solid-State and Solid-State fermentation. In submerged fermentation with a combination of malt 20%, glucose 4%, sucrose 2% and with aeration 98.3±3.78mg/g EPS were observed. FTIR band in 890 Cm-1 indicated the presence of polysaccharides.Discussion and conclusion: Among the three sets of formulations, results showed that Semi-Solid-State fermentation is the most appropriate culture for GA production and submerged fermentation is the most appropriate culture for EPS production. Finally, we suggest Semi-Solid-State fermentation for both GA and EPS production using wholly submerged glucose and oak chips enriched solid particle.

Introduction: In recent years, there has been a considerable interest in the use of biological approaches, as an alternative to chemical fertilizers and pesticides to management of plant pathogens and improvement of crop productivity. Recently, endophytic bacteria have gained attention due to their efficient bio-control and plant growth promoting potentials. The objective of this study was to evaluate bio control and plant growth promoting ability of endophytic bacteria in challenging with Verticillium dahliae under in-vitro and greenhouse conditions.Materials and methods: Endophytic bacteria were isolated from tomato plants and their bio-control activity was screened based on dual culture method. Antifungal and their plant growth promoting traits such as production of volatile compounds, antibiotics, proteases, chitinases, hydrogen cyanide, siderophore, indole acetic acid and phosphate solubilizing were evaluated. Their effects on seed germination and growth parameters of seedlings under in-vitro condition and on the control of disease and tomato growth were evaluated in greenhouse.Results: In dual culture tests, FS67, FS167, FS300 and FS339 isolates showed significant antifungal activity and they were identified as Pseudomonas mosselli, P. fuorescence, Stenotrophomonas maltophilia and Acinetobacter calcoaceticus, respectively. All strains produced several kinds of antifungal and growth promoting agents under in-vitro conditions. They increased seed germination and growth parameters of seedlings. They also reduced the disease and improved the growth parameters of the plants in challenging with V. dahliae in greenhouse.Discussion and conclusion: The present study has shown that these endophytic bacteria have the bio-control and bio-fertilizer potentials, which make them suitable candidates as an alternative tool of chemicals in management of V. dahliae. Results indicated they might enhance tomato plant growth and health via various mechanisms and most of them probably employ more than one of these mechanisms.

Introduction: Extensive use of antibiotics led to the development of bacterial resistant to antibiotics. Medicinal plants can be alternative choice for antibiotics. The plant (Hyssopus officinalis) belongs to Lamiaceae family recently were attracted as a source for antimicrobial agents. The aim of this study was to evaluate the antibacterial and inhibitory activity of H. officinalis extract on the growth of six antibiotic-resistant bacteria.Materials and methods: In this study, ethanolic and methanolic extracts of H. officinalis were prepared. Antibacterial activity of the ethanolic and methanolic extracts was evaluated by paper disc diffusion method. Also, MIC and MBC of these extracts were determined for six pathogenic bacteria. The effect of these extracts on biofilm of bacteria (biofilm formation and destruction) was evaluated by microtiter plate method. The chemical composition of the extract was identified by GC-MS.Results: The results of study showed the maximum inhibitory effect of these extracts against planktonic forms belong to Staphylococcus aureus and Pseudomonas aeruginosa. Between all studied bacteria, Acinetobacter baumannii showed the greatest sensitivity to H. officinalis extracts in Muller Hinton broth (MIC= 3.125 mg ml-1). The highest inhibitory effects of H. officinalis ethanolic extract on biofilm formation were observed against Escherichia coli (95 %). The results of biofilm destruction showed that Klebsiella pneumoniae biofilm had a resistant biofilm structure between all tested bacteria (16.41 %). The GC-MS analysis revealed that five active compounds were present in the extract of this plant.Discussion and conclusion: The data obtained in this study confirmed that H.officinalis extract inhibit growth and biofilm formation of some pathogenic bacteria. It can be proposed for future studies that the compounds of this plant used for design a antimicrobial agent.

Introduction: In the aquaculture industry, yeasts like other microorganisms such as algae, play a major role. Yeasts can absorb minerals from their culture and is able to transfer nutritional materials to other organisms.Materials and methods: In this study, the effect of three concentrations (2.5, 5 and 7.5 g L-1) of organic (zinc-threonine) and inorganic (zinc-sulfate) zinc in culture media on the growth and enrichment of Saccharomyces cerevisiae was investigated. One group was also selected as the control treatment (each with 3 repetitions). Yeast culture was performed under standard conditions in YEPD medium and in 1-liter flasks. The amount of yeast added in the culture media was 10 g L-1.Results: Based on results, the most growth inhibitory of yeast was observed after adding 2.5 g L-1 of zinc threonine, and with increase in zinc amount in culture media, the growth rate increased but still significantly lower than zinc sulfate and control treatments. In the zinc sulfate groups, the growth inhibitory of yeast was observed after adding 7.5 g L-1 of zinc sulfate, but other treatments did not show significant difference with the control treatment. In this study, the highest zinc content (115.67±4.65 mg g-1) in yeast was observed in the treatment 7.5 g L-1 of zinc sulfate, which was significantly higher than other treatments (P<0.05). Consequently, zinc content of yeast in the zinc threonine group were lower than the zinc sulfate groups but in zinc threonine groups, the maximum zinc content (23.07±1.14 mg g-1) was observed in the treatment 5 g L-1 of zinc threonine, which was significantly higher than other treatments of this group (P<0.05).Discussion and conclusion: The present study showed that yeast could be enriched with both forms of zinc, but zinc sulfate induces the least growth inhibitory in the yeast and also Zn content after enrichment was higher in zinc sulfate treatments than zinc-threonine treatments.