Characterization and optimization of lipase activity produced by Pseudomonas monteilli 2403-KY120354 isolated from ground beef

A total of 56 Gram negative bacterial isolates were recovered from twenty ground beef samples and were screened for their potentiality to produce lipase. Forty four bacterial isolates were recorded as positive producers for lipase on tween as carbon source in solid medium. Also, the highly producer isolates were screened for lipase activity in submerged culture using olive oil as carbon and the most active isolate was 2043 which gave an activity of 20.0 ± 0.29 U/ml. The bacterial isolate 2403 was identified phenotypically according to Bergey’s Manual and genotypically using 16S rRNA genes analysis as Pseudomonas monteilli. Effect of some different factors on lipase activity were studied and the maximum lipase activity was achieved at reaction medium of pH 6 and incubated at 40°C for 60 min. Also, addition of Ba2+ in the reaction medium enhanced the lipase activity, while the other tested metals reduced the enzyme activity.Key words: Food contamination, lipase activity, olive oil, cultural conditions, Pseudomonas

Prevalence and Mycotoxigenic Potential of Fungi in Fish Feed Collected from Fish Farms in Egypt with a Particular Reference to Aflatoxins Contamination

  The current study is aimed to investigate the fungal contaminants in fish feed. Isolation of fungi was conducted on modified dichloran 18% glycerol agar (DG18) and potato dextrose agar (PDA). Feed samples were assayed for aflatoxins using HPLC. A total of 43 species belonging to 19 fungal genera recovered from 45 fish feed samples. Aspergillus and Penicillium were the most predominant genera with isolation frequency values indicated the retrieval capability of DG18 over PDA medium. For instance, Aspergillus spp. recorded 60%, 53.3% while Penicillium spp. were 33.3%, 17.8% on DG18 and PDA respectively via direct plating. 41.4% of the tested isolates were mycotoxin producers. Aflatoxins B1, B2, G1 and G2 were detected by 6 out of 10 screened Aspergillus isolates. Fumitremorgens, Gliotoxin, Ochratoxin A and B, and Zeralenone were also detected. The feed samples of high total count percentages (TC%) of A. flavus recorded the highest incidence of aflatoxins B2, G1 and G2 (2.3, 35.3 and 7.8 ng/g respectively). Meanwhile, the highest B1 concentration (3.7 ng/g) was recorded for the highest TC% interval studied (1:9 cfu/g). Thus, it is important to monitor the fungal load and mycotoxins in fish feed periodically using proper practical approaches

Prevalence and Mycotoxigenic Potential of Fungi in Fish Feed Collected from Fish Farms in Egypt with a Particular Reference to Aflatoxins Contamination

  The current study is aimed to investigate the fungal contaminants in fish feed. Isolation of fungi was conducted on modified dichloran 18% glycerol agar (DG18) and potato dextrose agar (PDA). Feed samples were assayed for aflatoxins using HPLC. A total of 43 species belonging to 19 fungal genera recovered from 45 fish feed samples. Aspergillus and Penicillium were the most predominant genera with isolation frequency values indicated the retrieval capability of DG18 over PDA medium. For instance, Aspergillus spp. recorded 60%, 53.3% while Penicillium spp. were 33.3%, 17.8% on DG18 and PDA respectively via direct plating. 41.4% of the tested isolates were mycotoxin producers. Aflatoxins B1, B2, G1 and G2 were detected by 6 out of 10 screened Aspergillus isolates. Fumitremorgens, Gliotoxin, Ochratoxin A and B, and Zeralenone were also detected. The feed samples of high total count percentages (TC%) of A. flavus recorded the highest incidence of aflatoxins B2, G1 and G2 (2.3, 35.3 and 7.8 ng/g respectively). Meanwhile, the highest B1 concentration (3.7 ng/g) was recorded for the highest TC% interval studied (1:9 cfu/g). Thus, it is important to monitor the fungal load and mycotoxins in fish feed periodically using proper practical approaches

Efficient Bioreduction of Sulfate from Industrial Wastewater Effluents Using Enterobacter cloacae emr69

This study aimed to isolate and characterize sulfur reducing bacteria from industrial wastewater and soil to remove sulfate. A total of 14 sulfate reducing bacterial (SRB) isolates were recovered from industrial wastewater and contaminated soil. Interestingly, bacterial isolate emr69 was selected as the highest sulfate reducer. Correspondingly, emr69 was characterized phenotypically and identified genotypically based on 16S rRNA gene sequencing as Enterobacter cloacae and deposited in Gen Bank database under accession number OR472728. The maximum sulfate reduction by E. cloacae emr69 against 2000 ppm (SO4-2) was 95% which obtained by adjusting the medium at pH 6 and growing the bacterium at 37°C under anaerobic conditions. The study suggests using of E. cloacae mr69 as a promising SRB for bioreduction of sulfate in industrial wastewater treatment

Optimization of lactic acid production by a novel strain, Enterococcus faecalis KY072975 isolated from infants stool in Egypt

Production of lactic acid using a novel strain of lactic acid bacteria isolated from infants stool was investigated in the present study. Out of ten isolates, a total of five bacterial isolates were found as positive in lactic acid production. The tested bacterial isolate W7 was observed as the potent strain in lactic acid production that exhibited a halo zone of 8 mm. The bacterial isolate W7 was identified phenotypically and genotypically as Enterococcus faecalis and was deposited in GenBank with accession number KY072975. The effect of different process parameters such as initial pH of the medium, incubation temperature, inoculum size and incubation time was also monitored to enhance lactic acid production and resulted in optimum lactic acid value of 0.72 mg/mL. The salted whey was the most applicable fermentation medium for production of lactic acid by Enterococcus faecalis KY072975 and recorded 2.07 ± 0.1 mg/mL