@article { author = {}, title = {Production of PHAs from Waste Frying Oil by Pseudomonas fluorescens S48 Using Different Bioreactor Feeding Strategies}, journal = {Egyptian Journal of Microbiology}, volume = {47}, number = {1}, pages = {1-15}, year = {2012}, publisher = {National Information and Documentation Center (NIDOC), Academy of Scientific Research and Technology}, issn = {0022-2704}, eissn = {2357-0881}, doi = {10.21608/ejm.2012.249}, abstract = {BBIODEGRADABLE polyesters, polyhydroxyalkanoate (PHAs) are promising candidates for the development of environment-friendly and totally biodegradable plastics. The production of PHAs by Pseudomonas fluorescens S48 was examined using bioreactor as one-stage batch, two-stage batch, and fed-batch (pulsed, continuous and high cell density) cultures. Corn oil , soybean oil (extracted from their meal) and two types of waste frying oils (WFO) were used in the productive medium as a carbon source. The highest values of polymer content in the one-stage bioreactor fermentation (52 % and 76.53 %) were obtained after 60 h on media supplemented with extracted corn oil and soybean oil, respectively. Whereas, the highest figure obtained on WFO type 2 was 30 % under the same circumstances. Using bioreactor as a two-stage batch culture increased the polymer content with soybean, corn oil and WFO type 2 by 2.2 %, 32.11 % and 58 %, respectively as compared with that obtained in one-stage batch culture. High-cell-density (0.64 gl-1) at continuous feeding rate 0.55mll-1h-1 of WFO type 2 recorded the highest polymer content, yield and conversion coefficient after 48 h. Moreover, this application increased the polymer content by 65.7 % than that obtained in onestage batch culture as well as reduced the fermentation period 12 hr}, keywords = {Pseudomonas fluorescens S48,PHAs,Batch,Two-stage batch,High-cell-density,Bioreactor}, url = {https://ejm.journals.ekb.eg/article_249.html}, eprint = {https://ejm.journals.ekb.eg/article_249_0b6d1a27e104c51b4445f2802d311510.pdf} } @article { author = {}, title = {Semi-scale Production of PHAs from Waste Frying Oil by Pseudomonas fluorescens S48}, journal = {Egyptian Journal of Microbiology}, volume = {47}, number = {1}, pages = {17-34}, year = {2012}, publisher = {National Information and Documentation Center (NIDOC), Academy of Scientific Research and Technology}, issn = {0022-2704}, eissn = {2357-0881}, doi = {10.21608/ejm.2012.250}, abstract = {THE PRESENT study aimed at developing a strategy to improve the production of polyhydroxyalkanoates (PHAs) by Pseudomonas fluorescens S48 using waste frying oil (WFO) as the sole carbon source. Several cultivations were set up to steadily improve nutrients supply to attain high cell density and high biopolymer productivity. The production of PHAs was examined in a 14 l bioreactor as one-stage batch, two-stage batch, and high-cell-density fed-batch cultures. The highest value of polymer content in one-stage bioreactor was obtained after 60 h (33.7 %). Whereas, the two-stage batch culture increased the polymer content to 50.1 % after 54 h . High-cell-density (0.64 g/l) at continuous feeding rate 0.55 ml/l/h of WFO recorded the highest polymer content after 54 h (55.34 %). Semi-scale application (10 l working volume) increased the polymer content in one-stage batch, two-stage batch, and high cell density fed-batch cultures by about 12.3 %, 5.8 % and 11.3 %, respectively, as compared with that obtained previously by the authors in 2 l fermentation culture. Six different methods for biopolymer extraction were done to investigate their efficiency for optimum polymer recovery. The maximum efficiency of solvent recovery of PHAs was attained by chloroform– hypochlorite dispersion extraction. Gas chromatography (GC) analysis of biopolymer produced by Pseudomonas fluorescens S48 indicated that it solely composed of 3-hydroxybutyric acid (98.7%). A bioplastic film was prepared from the obtained PHB. The nucleotide sequence of the 16S rRNA gene of the studied isolate showed 98-99% similarity with Pseudomonas spp. particularly the Egyptian strain named Ps. fluorescens EG 639838}, keywords = {Pseudomonas fluorescens S48,Polyhydroxyalkanoates,Two-stage batch,High-cell-density fed batch,Bioreactor,recovery}, url = {https://ejm.journals.ekb.eg/article_250.html}, eprint = {https://ejm.journals.ekb.eg/article_250_289ca5a94a67b0565d99bee1e06e5b46.pdf} } @article { author = {}, title = {In vitro Detection and Optimization of Streptokinase Production by Two Streptococcal Strains in a Relatively Low Cost Growth Medium}, journal = {Egyptian Journal of Microbiology}, volume = {47}, number = {1}, pages = {35-53}, year = {2012}, publisher = {National Information and Documentation Center (NIDOC), Academy of Scientific Research and Technology}, issn = {0022-2704}, eissn = {2357-0881}, doi = {10.21608/ejm.2012.251}, abstract = {THIS STUDY sought to demonstrate the optimization of streptokinase production. Enzyme production was monitored during the growth of both Streptococcus pyogenes and Streptococcus equisimilis in different media. Adjustment of the pH for culture media of S. pyogenes and S. equisimilis, every 12 hr during incubation, significantly increased the enzyme production levels, when both microbes were grown on Strep-base medium. The best carbon source for streptokinase production was glucose of both S. pyogenes and S. equisimilis, while mannitol and sorbitol were found to be less suitable carbon sources. Yeast extract and casein could be used as the primary source of organic nitrogen for streptokinase production when the microbes were allowed to grow on Strep-base medium. The highest levels of the enzyme production were obtained with 1.5 % (w/v) tryptone and 1.5 % (w/v) casein for S. equisimilis and S. pyogenes, respectively. Detection of streptokinase produced was by the common casein digestion method and by the more sensitive chromozym substrate digestion method. Moreover, the enzyme was assayed electrochemically using the protamine-sensitive electrode to compare different methods of detection. Results obtained from electrochemical method were very close to that obtained with other methods. These results offer an alternative and reliable method for streptokinase detection during microbial growth. It provides a faster and less expensive technique for streptokinase determination especially when there is a need to detect the enzyme in turbid media.}, keywords = {IN VITRO DETECTION AND OPTIMIZATION …}, url = {https://ejm.journals.ekb.eg/article_251.html}, eprint = {https://ejm.journals.ekb.eg/article_251_7698cb00cb56fde466c61a3e20f7fc7d.pdf} } @article { author = {}, title = {Production and Optimization of Alkaline Protease in Submerged Fermentation by Streptomyces rochei NRC 24}, journal = {Egyptian Journal of Microbiology}, volume = {47}, number = {1}, pages = {55-77}, year = {2012}, publisher = {National Information and Documentation Center (NIDOC), Academy of Scientific Research and Technology}, issn = {0022-2704}, eissn = {2357-0881}, doi = {10.21608/ejm.2012.252}, abstract = {THE PURPOSE of the present research was to study the.production of extracellular alkaline protease by a local isolate, Streptomyces rochei NRC 24, under submerged fermentation (SF) conditions. The isolate exhibited maximum enzyme production with fermentation medium composed of peptone, glucose, K2HPO4, MgSO4.7H2O, NaCl, and CaCl2. The studies on environmental parameters revealed that maximum level of alkaline protease production (220.92 U/ml) was achieved during stationary phase of S. rochei NRC 24 with optimum initial pH 9, inoculum size of 2% from stock spore suspension (5.6 x 106 spores/ml), and with a culture volume of 75 ml in 250 ml Erlenmeyer flasks under shaking conditions of 200 rpm. Of different nitrogen sources, casein and peptone with 0.4% of each proved to achieve the maximum level of enzyme production. Screening experiments on medium components showed that the presence of peptone, glucose, MgSO4.7H2O, NaCl, and CaCl2 was essential for alkaline protease production. The absence of K2HPO4 from the medium did not totally influence the enzyme production. Based on these results, De Meo's fractional factorial design was applied to find out the optimal conditions for maximal alkaline protease production. Optimization of the medium was carried out in three steps and Streptomyces rochei NRC 24 grew in the optimized medium producing 555.61 U/ ml compared to the growth of the strain on the basal medium before optimization (224 U/ ml).}, keywords = {Streptomyces rochei NRC 24,Alkaline protease,productin,Optimization,De Meo's fractional factorial design}, url = {https://ejm.journals.ekb.eg/article_252.html}, eprint = {https://ejm.journals.ekb.eg/article_252_46d038e478ce64737f140532d8b0ba43.pdf} } @article { author = {}, title = {Screening of Some Fungal Isolates for Lipase Production and Optimization of Cultural Conditions for the Most Potent Isolate}, journal = {Egyptian Journal of Microbiology}, volume = {47}, number = {1}, pages = {79-95}, year = {2012}, publisher = {National Information and Documentation Center (NIDOC), Academy of Scientific Research and Technology}, issn = {0022-2704}, eissn = {2357-0881}, doi = {10.21608/ejm.2012.253}, abstract = {SIXTEEN Fungal isolates were screened for lipase production.Trichoderma viride was the most promising isolate for lipase activity. Lipase production has been optimized by this isolate using the following conditions; pH 6.0, temperature 25oC and 6 days of incubation. Moreover, the enzyme production has been enhanced by supplementing the production medium with egg yolk as the only carbon source. Starch also resulted in an increase in lipase production. The production of the lipase enzyme in medium devoid from the lipid sources proves that this lipase is partially a constitutive enzyme. Fungal discs have been found to be the most suitable inoculum. Aeration has been proved to be favored for lipase production. The static condition was advantages than the agitation for the lipase activity. Peptone as organic N-source, sodium nitrate as inorganic N source and KH2Po4 as phosphate source were more suitable for lipase production. One tenth percent oil concentration (w/v) was the best for lipase production.}, keywords = {Lipase,Trichoderma viride.}, url = {https://ejm.journals.ekb.eg/article_253.html}, eprint = {https://ejm.journals.ekb.eg/article_253_4fec4532f7828695632c27618bb882a5.pdf} } @article { author = {}, title = {Thiamine and Pyridoxine Alleviate Oxidative Damage by Copper Stress in Green Alga Chlorella vulgaris }, journal = {Egyptian Journal of Microbiology}, volume = {47}, number = {1}, pages = {97-110}, year = {2012}, publisher = {National Information and Documentation Center (NIDOC), Academy of Scientific Research and Technology}, issn = {0022-2704}, eissn = {2357-0881}, doi = {10.21608/ejm.2012.254}, abstract = {THIAMINE and pyridoxine were investigated for their capacity to .alleviate oxidative damage by copper stress on a local alga (C. vulgaris). Lower levels of Cu+2 induced a slight stimulation in growth criteria (growth rate & dry weight), photosynthetic pigments (0.5µM) and O2-evolution (0.5, 10 µM) of C. vulgaris which was inhibited by high Cu+2 concentrations. In contrast, O2-uptake was retarded at the lower Cu+2 levels then significantly increased by increasing the Cu+2 in algal cultures. Proline, MDA contents, and antioxidant enzyme activity of C. vulgaris markedly increased under Cu+2 stress. On the other hand, the addition of thiamine or pyridoxine alleviated the oxidative damage of Cu+2 on C. vulgaris growth and enhanced growth, pigment contents, O2- evolution, and antioxidant enzyme activity in the algal cultures compared to reference controls. While O2-uptake, proline content, and lipid peroxidation levels were decreased, thiamine or pyridoxine scavenger systems might be important for supporting the ability of C. vulgaris to resist copper toxicity}, keywords = {copper sulfate,Green alga,Thiamine,Pyridoxine,Antioxidant enzyme,Lipid peroxidation,proline}, url = {https://ejm.journals.ekb.eg/article_254.html}, eprint = {https://ejm.journals.ekb.eg/article_254_7f21579110a5ca711c90f85b181fb736.pdf} } @article { author = {}, title = {Studies on The Antibacterial Activity of Some Free and Entrapped Bacteriophages against Fish Pathogens}, journal = {Egyptian Journal of Microbiology}, volume = {47}, number = {1}, pages = {111-125}, year = {2012}, publisher = {National Information and Documentation Center (NIDOC), Academy of Scientific Research and Technology}, issn = {0022-2704}, eissn = {2357-0881}, doi = {10.21608/ejm.2012.255}, abstract = {THREE DIFFERENT bacteriophages namely VPS1, APS2 and APS3 were isolated from crab (Callinectes sapidus), clams (Tapes decussatns) and fish (Tilapia sp.) samples. They belong to families Siphoviridae, Myoviridae and Podoviridae, respectively. Statistical analysis based on analysis of phages DNA by using random amplification of polymorphic DNA-polymerase chain reaction (RAPD-PCR) revealed that the similarity levels were different among the three phages. Entrapment of VPS1 and APS2 was carried out into calcium alginate beads. The antibacterial activity of VPS1 and APS2 were tested before and after entrapment in Ca-alginate beads against some fish pathogenic bacteria such as Vibrio anguillarum and Aeromonas hydrophila. VPS1 seeded beads were superior (significant at P<0.05) from the free phages in the reduction of the growth rate of V. anguillarum while, APS2 seeded beads exhibited lower efficiency in the reduction of A. hydrophila growth rate. Antibacterial activity of entrapped VPS1 was studied during 7 successive cycles. VPS1 was successful (significant at P<0.05) in the reduction of V. anguillarum growth rate. A successful trial showed the good applicability of entrapped VPS1 in reduction of 97% of the pathogenic Vibrio spp. in the water sample from El-Mex fish farm after 3 h. Chemical characterization of plain and phage seeded beads was performed by using Fourier transform infrared spectroscopy (FTIR).}, keywords = {Antibacterial,Bacteriophages,Ca-alginate beads. Entrapment}, url = {https://ejm.journals.ekb.eg/article_255.html}, eprint = {https://ejm.journals.ekb.eg/article_255_2c76fdec09280616ceb45f1a664c1a3d.pdf} } @article { author = {}, title = {Studies on Incidence and Prevention of Nosocomial Infection of Urinary Tract Endoscopies by Different Antimicrobial Agents}, journal = {Egyptian Journal of Microbiology}, volume = {47}, number = {1}, pages = {127-140}, year = {2012}, publisher = {National Information and Documentation Center (NIDOC), Academy of Scientific Research and Technology}, issn = {0022-2704}, eissn = {2357-0881}, doi = {10.21608/ejm.2012.256}, abstract = {THIRTY FIVE bacterial isolates were collected from urine and blood samples of 20 patients, before and after endoscopy examination, in new Surgical Hospitals , Zagazig University Hospital, Zagazig, Egypt. Antibiotic susceptibility profile of purified bacteria revealed four multi-resistant strains identified as Staphylococcus aureus Zag11, Pseudomonas aeruginosa Zag60, Escherichia coli Zag126 and Staphylococcus epidermidis Zag128. The four selected bacteria were subjected to some disinfectants (glutaraldehyde, hydrogen peroxide, P3-oxonia and Orthophthaladehyde) at different concentrations and different exposure times. It was observed that 10 min were enough to inhibit the growth of tested pathogenic bacteria in case of (8% H2O2 & 0.55% orthophthaladehyde) while completely inhibition was recorded after 15min in the case of (2.2% glutaraldehyde, 70% ethanol, and 0.45% P3-oxonia). Sterile urinary tract endoscopy was artificially contaminated with mixture (1:1:1:1:1:1) of six clinical pathogenic bacterial strains comparing with the four tested bacterial strains. Upon exposing the contaminated endoscope to different chemical disinfectants; 8% hydrogen peroxide and 0.55% Orthophthalaldehyde inhibited after 30 min exposure while 2.2% Glutaraldehyde, 0.45% P3oxonia, and 70% Ethanol needed 60 min for complete bacterial inhibition. Upon exposure of artificially contaminated endoscope to different physical agents (U.V, γ- rays and dry hot air), Gamma rays showed maximum inhibitory action.}, keywords = {Nosocomial infection,Urinary tract endoscopies,antimicrobial agent}, url = {https://ejm.journals.ekb.eg/article_256.html}, eprint = {https://ejm.journals.ekb.eg/article_256_4cc6acf07e6f6821d172d379ac65d1ad.pdf} } @article { author = {}, title = {Antimicrobial Activity of Endophytic Fungi Isolated from Avicennia marina Plant, Red Sea, Egypt}, journal = {Egyptian Journal of Microbiology}, volume = {47}, number = {1}, pages = {141-152}, year = {2012}, publisher = {National Information and Documentation Center (NIDOC), Academy of Scientific Research and Technology}, issn = {0022-2704}, eissn = {2357-0881}, doi = {10.21608/ejm.2012.257}, abstract = {TWENTY ONE endophytic species were isolated from 360 segments of Avicennia marina from two different locations of Red Sea mangrove forest in 2009 to 2010. Some of the endophytes were identified to genus or species level using traditional morphological methods, but most were classified as sterile mycelia. The isolated species belonged to 7 genera (Acromonium, Aspergillus, Chaetomium, Cladosporium, Fusarium, Phoma and Ulocladium). Thirty nine isolates of endophytic fungi were selected to detected their antagonistic abilities against Bacillus subtilis, Staphylococcus aureus, Micrococcus luteus, Escherichia coli, Aspergillus niger and Alternaria alternate. The obtained results indicated that some isolates of the same species showed different behavior against used bacteria , while few of these isolates of the same species showed the same behavior. The tested endophytic species did not show any antagonistic ability against Aspergillus niger and Alternaria alternate.}, keywords = {}, url = {https://ejm.journals.ekb.eg/article_257.html}, eprint = {https://ejm.journals.ekb.eg/article_257_1253cde840a49549eca9eb5a816ed0e3.pdf} } @article { author = {}, title = {Antiviral Effects of the Liquid Culture, Cell Free Supernatants and Extracellular Products from Serratia marcescens subsp. marcescens against Watermelon Mosaic Virus (WMV)}, journal = {Egyptian Journal of Microbiology}, volume = {47}, number = {1}, pages = {153-170}, year = {2012}, publisher = {National Information and Documentation Center (NIDOC), Academy of Scientific Research and Technology}, issn = {0022-2704}, eissn = {2357-0881}, doi = {10.21608/ejm.2012.258}, abstract = {THIS STUDY was to specify the potential antiviral action of Serratia marcescens subsp. marcescens and its extracellular products against watermelon mosaic virus (WMV). The highest level of protection observed occurred in experiments, where bacteria were mixed with the virus in vitro before inoculation, resulting in gave 100% viral inhibition. S. marcescens significantly improved (p< 0.05) several growth parameters in all experiments compared to viral control. The highest level of virus inhibition obtained when a mixture of all compounds extracted and purified from S. marcescens subsp. marcescens was applied to cucumber plants reducing infection by 95% . The results of RT-PCR showed that in vitro liquid bacterial culture treatment and applied 24 hr after virus inoculation treatment highly reduced the accumulation of WMV in treated plant leaves . The usage of S. marcescens in vitro and in vivo led to increasing in total protein, polyphenoloxidase, and phenolic compounds compared to viral-infected and healthy controls, while reducing glutathione oxidase. S. marcescens and its metabolic products found in culture filtrates show promise as an effective biocontrol agent for WMV infection in plants and appear to promote plant growth even in the absence of virus}, keywords = {}, url = {https://ejm.journals.ekb.eg/article_258.html}, eprint = {https://ejm.journals.ekb.eg/article_258_0f55ec1e1245bf9d6e7b3b5e3ff5bdfd.pdf} } @article { author = {}, title = {Detection of Six E. coli O157 Virulence Genes in Water Samples Using Multiplex PCR}, journal = {Egyptian Journal of Microbiology}, volume = {47}, number = {1}, pages = {171-188}, year = {2012}, publisher = {National Information and Documentation Center (NIDOC), Academy of Scientific Research and Technology}, issn = {0022-2704}, eissn = {2357-0881}, doi = {10.21608/ejm.2012.259}, abstract = {ESCHERICHIA COLI O157 strains have emerged as important human enteric pathogens. E. coli O157 strains may be transmitted in a variety of ways, including drinking water, recreational water, and wastewater. One hundred and seventy five water samples were collected from different water sources from June 2010 to July 2011 and examined for classical bacterial indicators (total bacterial counts at 37oC and 22oC, total coliforms, fecal coliforms and fecal streptococci) and E. coli O157. Total coliforms (TC), fecal coliforms (FC) and fecal streptococci (FS) among the collected water samples were 83, 76 and 76 out of 175 (MPN- index/100 mL) with the incidence ratio of 47%, 43%, and 43%, respectively. Escherichia coli O157 was detected in water samples using HiCrome EC O157:H7 agar and multiplex PCR targeting six virulence genes {stx1 (Shiga toxin 1 gene), stx2 (Shiga toxin 2 gene), eae (intimin gene), hlyA (hemolysin gene), rfbE (O157 antigen gene), and fliC (flagellar antigen gene)}. The sensitivity test showed that the multiplex PCR amplified genes with a minimum of 100 CFU of E. coli O157. Conventional method using HiCrome media indicated that 57 out of 175 examined water samples (32%) contained E. coli O157. The multiplex PCR indicated that 60 water samples were positive for at least one of the six targeted virulence genes. The most prevalent virulence genes in E. coli O157 isolates were Shiga toxin 2 gene (stx2) (98%), intimin gene (eae) (98%) and O157 antigen gene (rfbE) (98%) followed by Shiga toxin 1 gene (stx1) (84%) then flagellar antigen gene (flic) (66%) while Hemolysin gene (hlyA) (0%) was not detected in any E. coli O157 isolates.}, keywords = {E. coli O157,virulence gene,Multiplex PCR,water}, url = {https://ejm.journals.ekb.eg/article_259.html}, eprint = {https://ejm.journals.ekb.eg/article_259_deb6a43822c542d57c879bf5317b659b.pdf} }