Thirty-one bacterial isolates out of 133 isolates, were obtained from rhizosphere of Egyptian clover plants, and had variant capability for starch degradation on starch agar medium. The isolate E109 was the most potent being 72.5 U ml À1 and 2.5 for amylase activity and starch hydrolysis ratio (SHR), respectively, at 50°C. The potent isolate E109 was identified based on phenotypic characteristics, phylogenetic positions based on 16S rRNA gene analysis and base sequences (submitted to NCBI Gen Bank). 16S rRNA gene analysis confirmed that this isolate belonged to the genus Bacillus and it was most closely related to B. amyloliquefaciens (95% similarity). For the production of amylases, nine agro-industrial residues were added as carbon sources to the basal medium. The medium supplemented with potato starchy waste as the sole carbon source enhanced the enzyme activity more than soluble starch as control for a, b and c amylases activity, as it increased by B. amyloliquefaciens about 1.26 & 4 and 8-fold, respectively after 48 h at 50°C using rotary shaker at 150 rpm. B. amyloliquefaciens gave the maximum values of a, b and c amylases activity on medium supplemented with 2% potato starchy waste after 30, 30 & 36 h of fermentation periods at 50°C using shake flasks technique as a batch culture. These values were 155.2 U ml À1 (R 2 = 0.93), 1.0 U ml À1 (R 2 = 0.94) and 2.4 U ml À1 (R 2 = 0.95), respectively. It could be stated that productive medium supplemented with 2% potato starchy waste as a low price substrate could be more favorable than basal medium containing 1% starch for amylases production in submerged fermentation, as it increased a, b and c amylase activity by 1.98, 7.69 and 12-fold than that produced in basal medium (control), respectively. ª 2015 Production and hosting by Elsevier B.V. on behalf of Faculty of Agriculture, Ain Shams University.

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Background: Food-borne diseases pose serious health problems, affecting public health and economic development worldwide.Methods: Salmonella was isolated from samples of chicken parts, skin samples of whole chicken carcasses, raw egg yolks, eggshells and chicken faeces. Resulting isolates were characterised by serogrouping, serotyping, antimicrobial susceptibility testing and detection of extended-spectrum β-lactamase (ESBL) production. Antibiotic resistance genes and integrons were identified by polymerase chain reaction (PCR).Results: The detection rates of Salmonella were 60%, 64% and 62% in chicken parts, skin, and faeces, respectively, whereas the egg yolks and eggshells were uniformly negative. Salmonella Kentucky and S. Enteritidis serotypes comprised 43.6% and 2.6% of the isolates, respectively, whilst S. Typhimurium was absent. Variable resistance rates were observed against 16 antibiotics; 97% were resistant to sulfamethoxazole, 96% to nalidixic acid and tetracycline and 76% to ampicillin. Multidrug resistance was detected in 82% (64/78) of the isolates and ESBL production was detected in 8% (6/78). The β-lactamase blaTEM-1 gene was detected in 57.6% and blaSHV-1 in 6.8% of the isolates, whilst the blaOXA gene was absent. The sul1gene was detected in 97.3% and the sul2 gene in 5.3% of the isolates. Sixty-four of the 78 isolates (82%) were positive for the integrase gene (int I) from class 1 integrons, whilst int II was absent.Conclusion: This study reveals the presence of an alarming number of multidrug-resistant Salmonella isolates in the local poultry markets in Cairo. The high levels of drug resistance suggest an emerging problem that could impact negatively on efforts to prevent and treat poultry and poultry-transmitted human diseases in Egypt.

The present study aimed at developing a strategy to improve the volumetric production of PHAs by Pseudomonas fluorescens S48 using waste frying oil (WFO) as the sole carbon source. For this purpose, 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 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 PHA 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-hydrobutyric acid (98.7%). A bioplastic film was prepared from the obtained PHB. The isolate studied shares the same identical sequence, which is nearly the complete 16S rRNA gene. The identity of this sequence to the closest pseudomonads strains is about 98–99%. It was probably closely related to support another meaningful parsiomony analysis and construction of a phylogenetic tree. The isolate is so close to Egyptian strain named EG 639838.

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