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Hyperbranched polyamidoamine (PAMAM) has a high density of surface amino groups. This feature was exploited in the surface modification of κ-carrageenan gel beads for successful protease immobilization. The optimum PAMAM pH was at 2.1 and 9.3. However, treatment of κ-carrageenan gel beads at the higher pH showed re-usability for more than seven successive times. As a result of central composite design optimization, the maximum immobilization yield was obtained by soaking 8 U for 24 h. The comparative thermodynamics studies showed an enhancement in the thermal stability at high temperature for the immobilized protease as well as increased half-life time from 24.06 min to 79.95 min. Also, the D-values increased from 165.03 min to 548.23 min for free and immobilized enzyme, respectively. Moreover, the enzyme stability enhancement for the immobilized protease catalyst was accompanied with a remarkable increase in the enthalpy and in the free energy. Immobilized protease onto Carr-PAMAM gel beads can retain 89% of its initial activity and lost only 11% after 8 weeks of storage at 4 °C. Furthermore, an effective removal of silver from used X-ray film by the immobilized protease was achieved for six repeated cycles. Unlabelled Image [ABSTRACT FROM AUTHOR]

Twelve bacterial strains were isolated from beehives of Yemen, Nigerian and Libyan honey bee. All the isolates showed dextransucrase activity with degrees of variation. Esawy-1 recorded the highest activity (10.53) and was identified morphologically and based on 16S rRNA as Enterococcus faecalis . Some isolate safety was assessed such as hemolytic activity and resistance to antibiotic. The isolate showed sensitivity to most tested antibiotic such as levofloxacin, ofloxacin, ciprofloxacin and vancomycin. Also, the hemolytic activity was negative. A 2- level Plackett–Burman design was used to determine the bioprocess parameters that affected dextransucrase productivity. Central composite design was consequently showed 6.70-fold improvement in dextransucrase productivity in compared to the basal medium. Also, the results showed a 96% correlation between sucrose concentration and the amount of dextran yield. FTIR and 1HNMR spectrum confirmed that the formed polysaccharide was dextran comparing to a standard dextran. Enterococcus faecalis Esawy KR758759 dextran showed a fibrinolytic activity matching the standard Hemoclar preparation (40%) while the anticoagulation activity was negative. Also, it recorded a promising prebiotic against Lactobacillus casie (1.82). All previous results recommended the Enterococcus faecalis dextran to be used in food and pharmaceutical fields and paid attention to the honey as a source of potential bacterial dextransucrase. [ABSTRACT FROM AUTHOR]

Previously, Bacillus subtilis HMNig-2 and Bacillus subtilis MENO2 exhibited in vitro promising probiotic characteristics. They were tolerant to pH, bile salts, pancreatic enzymes, exhibited antimicrobial activity against pathogens and had ability to form biofilm. These strains also showed the highest levansucrase production and levan yield. In this study, the impact of the two Bacillus subtilis isolates and their levans were assessed in vivo in a mouse model. A novel correlation between the probiotic properties of the strains and their yielded levans was studied in terms of their effect on gut microbiota, immune system improvement and protection from Salmonella typhimurium infection that could cause liver inflammation and hepatic infiltration. Generally, the synbiotic strain (HMNig-2 and its levan) recorded the best results in lowering the coliform count by 1.5 log while increasing Lactobacillus bacteria count in gut by almost 0.8 log. Furthermore, it achieved the highest total IgA (22.4 µg/mL), IgG (115.2 µg/mL) and lysozymes concentrations (81.6 U/mL) compared to 14.1 (µg/mL), 98.8 (µg/mL) and 64.5 (U/mL) of control, respectively indicating its beneficial role in immune system improvement. Results suggested that interaction between the probiotic strains with their levan could be used as synbiotics providing optimal liver protection against pathogen complications as shown by normal hepatic lobules and portal tracts. Levans of isolate B. subtilis HMNig-2 and B. subtilis MENO2 showed free radical scavenging activity of 48% and 40%, respectively. Results suggest the worth of studying further the possible applications of honey isolates and their products in health protection. [ABSTRACT FROM AUTHOR]

Abstract: Phytase production by Penicillium purpurogenum GE1 isolated from soil around bean root nodules was investigated by solid state fermentation (SSF) using mixed substrates consisted of corn cob and corn bran. The SSF conditions were optimized by using one-variable–at-a-time strategy. The optimum conditions for phytase production were at 27°C, pH 8 and 66% moisture content. The study of different carbon and nitrogen sources revealed that glucose and peptone registered the highest enzyme productivity (92±5.6U/g ds, 125±4.9U/g ds). Among different surfactants, maximum phytase productivity was observed with Tween 80 at 0.001 concentrations (170±4.2U/gds). A Box–Behnken design was employed to investigate the optimization of the most significant variables affecting the enzyme production. Maximal phytase production was detected after the addition of (g/5gds): 0.75 glucose, 0.375 peptone and 0, 01 tween 80. This result represented an improvement in phytase production of 2.6 folds when compared to that previously obtained using the basal medium under the same cultivation conditions. The generated model was found to be very adequate for phytase production (90% accuracy) as the experimental value was 444±3.5U/gds compared to 401U/gds for the predicted value. In brief, the production of phytase using corn cob and corn bran is a novel and cheap way for the production of this important enzyme and opens a new way for researchers to discover and explore this arena. [Copyright &y& Elsevier]

New pyranocoumarin and coumarin-sulfonamide derivatives were prepared and evaluated for their antioxidant, antimicrobial, and/or anti-inflammatory activities. Coumarin-sulfonamide compounds 8a–d demonstrated significant antioxidant activity, while 7c,d, 8c,d, and 9c,d exhibited antimicrobial activity equal to or higher than the standard antimicrobials against at least one tested microorganism. Regarding the anti-inflammatory testing, pyranocoumarins 2b, 3a,b and 5c and coumarin-sulfonamide compound 9a showed more potent antiproteinase activity than aspirin in vitro; however, five compounds were as potent as aspirin. The anti-inflammatory activity of the promising compounds was further assessed pharmacologically on formaldehyde-induced rat paw oedema and showed significant inhibition of oedema. For in vitro COX-inhibitory activity of coumarin derivatives, pyranocoumarin derivative 5a was the most selective (SI = 152) and coumarin-sulfonamide derivative 8d was most active toward COX-2 isozyme. The most active derivatives met the in silico criteria for orally active drugs; thus, they may serve as promising candidates to develop more potent and highly efficient antioxidant, antimicrobial, and/or anti-inflammatory agents. [ABSTRACT FROM AUTHOR]

Alginate- polyethyleneimine gel beads modified by using 0.3 M Na+ were used for covalent immobilization of Aspergillus flavus xylanase. SEM images showed distorted structure with addition of Na+ that impaired the egg-box structure formation offered much covalent binding with xylanase. Immobilization onto (Alg+PEI/Na+) showed an enhancement in the operational stability, immobilization efficiency as well as immobilization yield. Covalent immobilization of xylanase onto (Alg+PEI/Na+) enhanced xylanase activity over a wide range of pHs (4–5.5) comparable to its free formula. As well as an increase in reaction temperature up to 60°C. However, immobilized formula of enzyme showed abroad thermal stability that it retained 79.0% of its initial activity at 70°C up to 30 min whereas, free formula completely lost its activity at this temperature. Thermodynamics studies showed an enhancement in thermal stability at high temperature for the immobilized xylanase. i.e. At 70°C the t 1/2 and D-value for free formula of enzyme increased from 24 to165 min and from 79.95to 548.23 min, respectively. Moreover, the enzyme stability enhancement for immobilized formula of xylanase was proved with a remarkable increase in enthalpy and free energy. 93% of the immobilized xylanase activity was retained over 6 weeks of storage at -4°C. [ABSTRACT FROM AUTHOR]

Pectinase produced by a honey derived from the fungus Aspergillus awamori KX943614 was covalently immobilized onto gel beads made of alginate and agar. Polyethyleneimine, glutaraldehyde, loading time and enzyme's units were optimized by 2 4 full factorial central composite design (CCD). The immobilization process increased the optimal working pH for the free pectinase from 5 to a broader range of pH 4.5–5.5 and the optimum operational temperature from 55 °C to a higher temperature, of 60 °C, which is favored to reduce the enzyme's microbial contamination. The thermodynamics studies showed a thermal stability enhancement against high temperature for the immobilized formula. Moreover, an increase in half-lives and D-values was achieved. The thermodynamic studies proved that immobilization of pectinase made a remarkable increase in enthalpy and free energy because of enzyme stability enhancement. The reusability test revealed that 60% of pectinase's original activity was retained after 8 successive cycles. This gel formula may be convenient for immobilization of other industrial enzymes. [ABSTRACT FROM AUTHOR]