eng
National Information and Documentation Center (NIDOC), Academy of Scientific Research and Technology
Egyptian Journal of Microbiology
0022-2704
2357-0881
2009-12-31
44
1
1
14
10.21608/ejm.2009.282
282
Original Article
Inhibitory Effect of Egyptian Garlic Extract on Penicillic Acid Production
THE INHIBITORY effects of aqueous Egyptian garlic extract on growth and penicillic acid production of Penicillium hirsutum were established. Minimal inhibitory concentration (MIC) of the aqueous garlic extract was determined by the agar diffusion assay, which was 30 mg/ml. Growth of the fungus in broth containing higher concentrations of garlic extract (18 and 24 mg/ml) showed that sporulation was completely inhibited after 7 days of incubation or became very slight after 10 days at these mentioned concentrations. The increase in garlic concentration caused a gradual increase in the average values of mycelial dry weights reaching a maximum at 24 mg/ml. In the contrary, the increase in garlic extract concentration induced a reduction in the levels of penicillic acid production. The amount of penicillic acid in presence of 24 mg/ml of garlic was approximately 44% that of control culture filtrate after 10 days of incubation, however penicillic acid was not detected completely at the same garlic extract concentration after 7 days of incubation. This study was also extended to analyze and evaluate the percentage of the main components in garlic extract that may be responsible for these inhibitory effects, applying GC-MS chromatographic analysis. This is the first report on the inhibition of penicillic acid production by a natural substance as garlic extract.
https://ejm.journals.ekb.eg/article_282_1691bf815cb6abe0a6c2d7b207859883.pdf
Garlic
Mycotoxins
Penicillic acid
antifungal activity
Penicillium hirsutum
eng
National Information and Documentation Center (NIDOC), Academy of Scientific Research and Technology
Egyptian Journal of Microbiology
0022-2704
2357-0881
2009-12-31
44
1
15
28
10.21608/ejm.2009.283
283
Original Article
Selection of Microencapsulation Method to Improve Antimicrobial Agents Production by Some Lactobacillus Species and Propionbacterium thoenii in Dairy Products
The Aim of this Research is to select the agreeable encapsulation method to improve antimicrobial production from Lactobacillus acidophilus, Lactobacillus reuteri, Lactobacillus rhamnosus and Propionibacterium thoenii, The effect of different organic acid concentrations (1 and 2w/v), different pH values (3,4,5,6,7 and 8), different temperature degrees (0,7,25,37 and 45⁰C) and storage temperature on viability of encapsulated bacteria were investigated. Also, the efficiency of microencapsulated methods (alginate + NaCl, alginate + oil and K-carrageenan) on enhancement of antimicrobial production were studied. Microencapsulation with alginate + NaCl offered greater production in extreme conditions (low pH, low temperature and in the presence of organic acids). In addition, this method was more effective against pathogenic bacteria by enhancement of antimicrobial production, thus it may be effectively used to increase the safety and the shelf-life of dairy products.
https://ejm.journals.ekb.eg/article_283_d41d8cd98f00b204e9800998ecf8427e.pdf
Microencapsulation
Antimicrobial
Lactobacillus spp
Propionibacterium thoenii
eng
National Information and Documentation Center (NIDOC), Academy of Scientific Research and Technology
Egyptian Journal of Microbiology
0022-2704
2357-0881
2009-12-31
44
1
29
46
10.21608/ejm.2009.284
284
Original Article
Biotechnological Application of Bacterial Alkaline Thermostable Enzymes in Bio-Detergent Industry
THIS is an investigation concerned with the production of alkaline thermostable microbial enzymes for application in biodetergent technology. Bacillus licheniformis- B42 and Geobacillus stearothermophilus – B78 were selected and identified among one hundred and fifty-three thermophilic bacterial isolates with respect to their ability to produce α-amylases, cellulases, proteases and lipases grown on some agro-industrial wastes at 55°C and at pH 9 for application in biodetergent technology. Productivity of four alkaline thermostable enzymes by both selected strains using slaughterhouse wastes (SHW) as best substrate for proteases and lipases and potato peel(PP) as best substrate for α-amylases and cellulases. The enzymatic level more affected by incubation temperature, pH, SHW and PP concentrations, inoculum size, incubation period, carbon, nitrogen, metal inducer and vitamins sources, under shaking conditions. Four alkaline thermostable enzymes were produced under all optimal nutritional and environmental conditions and purification by column chromatography on Sephadex G200 and G100 respectively were performed. Purification of four produced alkaline thermostable enzymes steps resulted in raising the purification fold to 17.04,15.24,411.9 and 27.33 times incomparable with crude enzymes for α-amylase, cellulase, protease, and lipase, respectively. The wash performing analysis of the four enzymes revealed that, it could effectively remove a variety of stains such as blood, apple, chocolate, mango, strawberry, salad and pomegranate by treatment at 55ºC for 15 min when alkaliphilic-thermostable crude/purified enzymes were added separately or in combination with or without detergent (Rabso) as an Egyptian local detergent product. The crude enzymes of these two bacterial strains proved to be potential candidates for the application of the detergent technology.
https://ejm.journals.ekb.eg/article_284_ddfcb4ce55b392bc1e8c3a78a93abe5e.pdf
Microbial enzymes
Alkaline thermostable enzymes
Geobacillus
Biotechnological application
Biodetergent
eng
National Information and Documentation Center (NIDOC), Academy of Scientific Research and Technology
Egyptian Journal of Microbiology
0022-2704
2357-0881
2009-12-31
44
1
47
59
10.21608/ejm.2009.285
285
Original Article
Patulin Production by Penicillium glabrumIsolated from Coffea arabica
COFFEE bean seeds in developing countries are of the crops, which found to be contaminated with toxigenic fungi. Accordingly, reduction of mycotoxins in coffee bean seeds has been a major mission of many studies in such countries. Five of thirty coffee bean seed samples collected from Jeddah were contaminated with patulin (30-48 μgkg-1). A toxigenic isolate of Penicillium glabrum was recovered from the contaminated samples. Factors affecting P. glabrum growth and patulin production included temperature and types of substrates were studied. The highest concentrations of patulin were produced at 20°C and in Coffee Dextrose (CD) medium. There was a significant correlation between ground coffee concentration in the liquid medium, P. glabrum growth and mycotoxin production. Increasing ground coffee concentrations in the CD medium increased fungal growth but decreased patulin production. Caffeine also decreased or inhibited mycotoxin production by P. glabrum when grown in liquid CD medium. Coffee in Saudi Arabia often is mixed with other plant materials or products. Addition of saffron or ginger to CD medium at 1g l-1 enhanced Penicillium growth and patulin production, addition of cardamom prevented mycotoxins production and allowed some fungal growth. On contrast, addition of cinnamon or cloves (1g l-1) inhibited both fungal growth and mycotoxins production. In conclusion, coffee beans are exposed to contamination with toxigenic fungal isolates. Ground coffee, caffeine, cardamom, cinnamon and cloves may prevent mycotoxin production.
https://ejm.journals.ekb.eg/article_285_4666e1b71e659bcb9c09abd045c01568.pdf
Saudi coffee
Coffea arabica
patulin
Penicillium glabrum
additives
Mycotoxins
Caffeine
Cinnamon
Cloves
cardamom
Natural antifungal
Antimycotoxin
eng
National Information and Documentation Center (NIDOC), Academy of Scientific Research and Technology
Egyptian Journal of Microbiology
0022-2704
2357-0881
2009-12-31
44
1
61
86
10.21608/ejm.2009.286
286
Original Article
Selection and Characterization of Bacteria Isolated from Petroleum Refining Effluents with Polycyclic Aromatic Hydrocarbons (PAHs) Removal Capacities and its Conditions
IN THIS STUDY, we evaluated the effect of different nutritional and environmental conditions on the percentages removal of PAHs present in petroleum refining effluent samples from the corrugated plate interceptor (API) of Cairo Oil Refining Co. (CORC), Egypt. Two hundred twelve and two hundred forty two bacterial strains were isolated from six petroleum refinery oil polluted effluents samples collected from CORC in summer and winter seasons, respectively which were selected due to their growing capacity in the presence of oil as sole carbon source. From these strains, four bacterial strains were further selected on the basis of their relatively good growing on hydrocarbon utilizing media, culture characteristics, and capacity to biodegrade PAHs. These bacterial isolates were identified on the basis of cell shape, cell arrangement, relation to oxygen and nutritional and biochemical characteristics. The four bacterial strains were found to belong to Pseudomonas oleovorans-W7DAFO22, Enterobacter cloacae-S7DAFI22, Pseudomonas stutzeri-S8API12 and Enterobacter aerogenes-W5OA31.They were capable of growing on the mineral salts media amended with crude oil as sole carbon source. Our results show that these strains can remove the PAHs by different percentages (%) at different pH values (4-9), NaCl concentrations (1-10%) and different nitrogenous and phosphorous sources. In conclusion, current sequence information provides the basis for a robust tool to estimate the PAHs degradation potential of different petroleum hydrocarbon contaminated sites undergoing in situ bioremediation.
https://ejm.journals.ekb.eg/article_286_775100c2e686484e0a236d9297cd2303.pdf
eng
National Information and Documentation Center (NIDOC), Academy of Scientific Research and Technology
Egyptian Journal of Microbiology
0022-2704
2357-0881
2009-12-31
44
1
87
99
10.21608/ejm.2009.287
287
Original Article
Production, Purification and Biochemical Characterization of Cyclodextrin Glucanotrans-ferase from Bacillus cereus N1
CYCLODEXTRIN glucanotransferase- (CGTase), (EC.2.4.1.19) producing bacteria were isolated from different sources of soils and identified as Bacillus cereus N1 and the best source was the soil of the National Research Centre. The maximum production of the crude CGTase enzyme was observed after 48hr of incubation at 37oC producing CGTase activity of 3.5 U/ml.
The effect of nutritional requirements on the CGTase production was carried out. Soluble starch and yeast extracts were found to be the best carbon and nitrogen sources, respectively.
The enzyme was successively purified by ammonium sulphate precipitation, DEAE-cellulose and Sephadex G-100 column chromatography and the final specific activity of CGTase enzyme was increased by 24 fold. The SDS-PAGE showed that the purified CGTase enzyme was homogenous and the molecular weight of the purified enzyme was about 75 kDa.
The characterization of the enzyme exhibited optimum pH and temperature at 6.0 and 40°C, respectively. The enzyme was stable at pH 6.5 to 8.0 and retained its high activity up to 45°C.
https://ejm.journals.ekb.eg/article_287_7dbfccae9f529c517c6402471524cd1c.pdf
Cyclodextin
Glucanotransferase
cyclodextrins
Bacillus cereus
-CD