Halophiles and Their Vast Potential in Biofuel Production

Global warming and the limitations of using fossil fuels are a main concern of all societies, and thus, the development of alternative fuel sources is crucial to improving the current global energy situation. Biofuels are known as the best alternatives of unrenewable fuels and justify increasing extensive research to develop new and less expensive methods for their production. The most frequent biofuels are bioethanol, biobutanol, biodiesel, and biogas. The production of these biofuels is the result of microbial activity on organic substrates like sugars, starch, oil crops, non-food biomasses, and agricultural and animal wastes. Several industrial production processes are carried out in the presence of high concentrations of NaCl and therefore, researchers have focused on halophiles for biofuel production. In this review, we focus on the role of halophilic microorganisms and their current utilization in the production of all types of biofuels. Also, the outstanding potential of them and their hydrolytic enzymes in the hydrolysis of different kind of biomasses and the production of biofuels are discussed

Comparison of the extracellular full-length and truncated recombinant protein A production in Escherichia coli BL21 (DE3)

     Protein A is a commercially important protein in biotechnological and medicinal applications. The great value of this protein and its applications in genetic and protein engineering and microbial researches as well as the growing use in biochemical industries, biotechnology, medicine and pharmacology, highlight the importance of the present study. In this survey the encoding genes of full-length and truncated forms of protein A were expressed in E. coli under an optimized expression condition. Optimization of the culture conditions resulted in an increase in expression and secretion of both forms of the protein, the pattern of expression and secretion levels for two forms was completely different. A minimum of 10-fold higher expression was observed for the truncated protein in comparison to that of the full-length recombinant form. Hydropathy plot of both forms of proteins showed that the missing domains in the truncated form contain groups of amino acids with high hydrophobicity score. Deletion of the terminal region could led to a higher expression level of the recombinant protein in E. coli. The function of these two proteins was studied using ELISA, which showed a higher activity for the truncated form for binding to IgG, compared to the full-length protein.

Production and Characterization of Biosurfactants Using Bacteria Isolated from Acidic Hot Springs

  Background and objective: Biosurfactants are increasingly used by food industries due to their low toxicities and unique structures. In this study, biosurfactants were produced and characterized for the first time using acidic bacteria isolated from acidic hot springs in Bushehr Province, Iran. Material and methods: Screening and identification of the most efficient species for biosurfactant production were carried out on 12 bacterial species using several experiments such as hemolysis, surface tension, emulsification index and diameter of clear zone. In addition to biosurfactant production, kinetics, stability and structural and thermal analysis were carried out for the bacterial strains using thin layer chromatography, Fourier Transform Infrared, nuclear magnetic resonance and differential scanning calorimetry. Results and conclusion: The biosurfactant from the selected bacteria (0.1 g l-1) was thermally stable at 120°C for 30 min. Stability at temperatures up to 140°C was confirmed using differential scanning calorimetry. The most significant novelty included the fact that the surface property was preserved until an osmolarity of 4% w v-1. Decreased surface tension and the emulsification potential were only reported at concentrations higher the highlighted concentration. Biological assay showed that Staphylococcus aureus was susceptible to produced biosurfactants, while no susceptibility was seen in Escherichia coli. Degeneration of SW480 cell line exposed to 0.601 µg µl-1 of the biosurfactant was detected after 24 h. The structural analysis showed that the biosurfactant was similar to surfactin as a food bioemulsifier. Conflict of interest: The authors declare that they have no conflict of interest

Development of quantitative competitive PCR for determination of copy number and expression level of the synthetic glyphosate oxidoreductase gene in transgenic canola plants

Background: For successful in vitro plant regeneration, plant cell lines with multiple transgene integration and low transgene expression levels need to be ruled out. Although real-time polymerase chain reaction (real-time PCR) is a rapid way to accomplish this, it is also expensive and typically limits the size of the target sequence. Quantitative competitive PCR (QC-PCR) is proven to be a safe and accurate method for determination of both copy number and quantification of transcript levels of synthetic transgenes in transformed plants.Results: The glyphosate oxidoreductase gene was chemically synthesized and used to transform Brassica napus L. via Agrobactrium -mediated transformation. A construct containing the mutated form of a synthetic glyphosate oxidoreductase (gox) gene (internal standard) was prepared. Gene copy number was estimated in nine independent transgenic lines using QC-PCR as well as the standard method of Southern blot analysis. By quantitative competitive reverse transcriptase PCR (QC-RT-PCR), transcript levels were also determined in these lines. High (> 3), medium to high (2.2-3), medium to low (1-2.2), and low (< 1) levels of transcript were detected. Conclusions: No direct relationship was found between copy number and transgene expression levels. QC-PCR method could be implemented to screen putative transgenic plants and quickly select single T-DNA inserts. QC-PCR methods and the prepared competitor construct may be useful for future quantification of commercial transgenic food and feed

Biological effects of low-dose ionizing radiation exposure on interventional cardiologists

Background Interventional cardiologists (ICs) are likely to receive high radiation exposure as a result of procedures they undertake.Aims To assess the effects of low-dose X-ray radiation exposure on chromosomal damage and on selectedindices of cellular and humoral immunity in ICs.Methods The study population consisted of 37 ICs and 37 clinical physicians as the control group with similarage, sex and duration of employment, without any work-related exposure to ionizing radiation. Cytogeneticstudies were performed by chromosome aberration analysis and immunological studies byflow cytometry, enzyme-linked immunosorbent assay and immunodiffusion techniques.Results The frequencies of aberrant cells, chromosome breaks and dicentrics plus centric rings were significantly higher in the exposed group compared to the control group (P , 0.05; P , 0.01; P , 0.001,respectively), without positive correlation between the frequency of dicentric and centric ring aberrationsand the cumulative doses of the ICs (r 5 0.24, not significant). A significant increase was observedin the expression of activation marker CD69 on TCD41 stimulated cells in serum immunoglobulin G and interleukin (IL)-2 (P , 0.05) and a significant decrease in serum IL-10 (P , 0.05) in the ICs compared with that of the control group. There was no statistical difference between the two groups in terms of number of white blood cells and lymphocytes, CD31, CD41 and CD81 T cells, CD191 and CD161 561 cells and concentrations of interferon (IFN)-g, IL-4, IL-6 and IL-8 cytokines.Conclusions While cytogenetic results show higher chromosomal damage, some immune responses are stimulated or modulated immunologically in ICs

Antibacterial Activity of Pseudonocardia sp. JB05, a Rare Salty Soil Actinomycete against Staphylococcus aureus

Staphylococcus aureus is a Gram-positive bacterium that causes many harmful and life-threatening diseases. Some strains of this bacterium are resistant to available antibiotics. This study was designed to evaluate the ability of indigenous actinomycetes to produce antibacterial compounds against S. aureus and characterize the structure of the resultant antibacterial compounds. Therefore, a slightly modified agar well diffusion method was used to determine the antibacterial activity of actinomycete isolates against the test microorganisms. The bacterial extracts with antibacterial activity were fractionated by silica gel and G-25 sephadex column chromatography. Also, the active fractions were analyzed by thin layer chromatography. Finally, the partial structure of the resultant antibacterial compound was characterized by Fourier transform infrared spectroscopy. One of the isolates, which had a broad spectrum and high antibacterial activity, was designated as Pseudonocardia sp. JB05, based on the results of biochemical and 16S rDNA gene sequence analysis. Minimum inhibitory concentration for this bacterium was 40 AU mL −1 against S. aureus. The antibacterial activity of this bacterium was stable after autoclaving, 10% SDS, boiling, and proteinase K. Thin layer chromatography, using anthrone reagent, showed the presence of carbohydrates in the purified antibacterial compound. Finally, FT-IR spectrum of the active compound illustrated hydroxyl groups, hydrocarbon skeleton, and double bond of polygenic compounds in its structure. To the best of our knowledge, this is the first report describing the efficient antibacterial activity by a local strain of Pseudonocardia. The results presented in this work, although at the initial stage in bioactive product characterization, will possibly contribute toward the Pseudonocardia scale-up for the production and identification of the antibacterial compounds

Effect of Various Carboxylic Acids on the Biosynthesis of Polyhydroxyalkanoate in Pseudomonas aeruginosaPA01: Biosynthesis of polyhydroxyalkanoate in Pseudomonas aeruginosa

In the present study, four carbon sources were tested for the polyester synthesis of Pseudomonas aeruginosaPA01 which is a ubiquitous environmental bacterium and is one of the top three causes of opportunistic human infections. These included linear C8to C11carboxylic acids. Octanoic acid, nonanoic acid, decanoic acid and undecanoic acid were added to M1 minimal medium to final concentrations of 60,40, 30 and 20 mM, respectively. When P. aeruginosa was cultivated in M1 minimal medium with decanoate and nonanoate as the sole carbon sources, polyhydroxyalka-noate (PHA) was achieved up to 55.75% (w/w) and 24.53% (w/w), respectively. The maximum PHAyield at 30 ºC was obtained when decanoic acid was used as sole carbon source. Use of nonanoic acid as carbon source was resulted in a minimum PHAyield at 30 ºC. An increase in the cultivation temperature from 30 ºC to 37 ºCresulted in decrease of PHAcontent and cell dried weight as well. Based on the type of carbon source different monomers at the level higher than 1 mol% to 62 mol%were detected which included 3-hydroxyoheptanoic acid (C7), 3-hydroxyoctanoicacid (C8), 3-hydroxynonanoic acid (C9), 3-hydroxydecanoic acid (C10), and 3-hydroxyundecanoic acid (C11)