生物加工与生物技术杂志

Thirteen Rhizobial isolates from root nodules of Faba beans (Vicia faba L.) were obtained from eleven governorates, representing different agro-ecological, agro-climatic and soil conditions in Egypt. A polyphasic approach, including phenotypic and genotypic techniques were used to study their diversity. Rhizobium isolates were examined for their ability to tolerate salt stress and antibiotic resistance. We used four NaCl concentrations ranging from 0.1%, 1%, 3% and 5% in liquid media and plates, moreover we used 24 different antibiotic disks to determine resistance or sensitive among the tested isolates on plates. The obtained results after salt tolerance and antibiotic response of the R. leguminosarium strains showed that the isolate No. RL9 was the superior strain for salt tolerance . The following strains for salt tolerance were the isolates (RL4) and (RL12), although the isolate No. RL11 was the superior strain for antibiotic resistant then isolates No. RL 13 and Rh3. Growth of all isolates were inhibited above 3% NaCl except five isolates RL4, RL9, RL10, RL12 and RL 13. Also the antibiotic resistance of the isolated strains showed a high level of resistance against Cefoxitin (FOX₃₀) and Cefuroxime (Cxm₃₀). The genetic diversity was studied using RAPD-PCR technique and we used specific primer (nodC) amplification. In this study we found that OPE₁₅ and OPG₀₄ primers showed the highest polymorphism level among the tested isolates, however OPJ₂₀ and OPC₀₆ primers showed the lowest polymorphism level.

Organic vapors are additional pervious than permanent gases within the composite membranes, with solvent and resolving permeability being concerning orders of magnitude beyond permanent gas permeableness. Gas and vapor transport properties were studied in mixed matrix membranes containing elastomeric ethylene-octene polymer (EOC or poly(ethylene-co-octene)) with 3 styles of carbon fillers: virgin or modify multi-walled carbon nanotubes (CNTs) for the open-chain organic compound (hexane), hydrocarbon (toluene), alcohol (ethanol), likewise as water for the representative samples. Gas permeableness of EOC lies between that of the additional pervious PDMS and also the less pervious semi-crystalline polythene and plastic. The results of the carbon-filled membranes supply views for application in gas/vapor separation with improved mechanical resistance.

Physico-chemical characteristics of four crude marine oils including farmed salmon, seal, cod liver and wild salmon are compared and interpreted with regard to their suitability as biodiesel feedstock. The physico-chemical properties including specific gravity, pH, ash content, acid value, iodine value, saponification value, p-anisidine value, peroxide value, TOTOX value, free fatty acid, flash point, kinematic viscosity, refractive index, lipid classes and fatty acid classification of all four marine oils were evaluated. The characterized marine oils were pale yellow to orange in color and stable in the liquid state at room temperature. The pH (6.5-6.8) values of all oils were neutral. The specific gravity (0.921-0.924 g/cm³), water content (179-325 ppm), ash content (0.0027-0.00455%), free fatty acids (0.03-1.23%), acid value (0.057-0.771 mg KOH/g), peroxide value (5.13-9.17 meq O₂/kg oil) and p-anisidine value (3.36-9.67) of all oils were within recommended limits except for higher water content in the seal oil (689 ppm), higher acid value in farmed salmon (2.441 mg KOH/g) and seal oil (0.958 mg KOH/g) and higher iodine value (116-139.15 g I2/100 g). A drying step needs to be implemented for the removal of water as it can lead to corrosion of internal combustion engine components. Due to higher iodine values, all the oils were drying oils except farmed salmon oil which was semidrying oil and susceptible to become rancid which causes reduction of pour point of biodiesel produced in the absence of antioxidant. All four marine oils were more likely to polymerize in the heat of the engine if used directly without trans-esterification. Flash point of all marine oils were above 200°C so, there is no risk of fire outbreaks in case of accidents. Due to higher triacylglycerol (81-93%) content, all the marine oils are suitable as a feedstock for biodiesel production via trans-esterification. Cod liver (14.72%) and wild salmon oil (9.92%) were rich in polar lipids while the farmed salmon (2.43%) and wild salmon (2.43%) were low in polar lipids. The phospholipids (1.21-1.67%) were higher than the recommended limit of ≤10 ppm so degumming process is required prior to biodiesel production. All the marine oils in this study have a high degree of unsaturation and polyunsaturated fatty acids and therefore the biodiesel produced from all oils will have less oxidation stability and result in the precipitation of the biodiesel components in a fuel feeding system or combustion chamber. Therefore, it is essential to stabilize the oil using an antioxidant immediately after extraction/production to obtain a high quality biofuel.

The extracts of Scots pine, Norway spruce, silver and white birches stem, bark, roots, leaves and needles contain several useful bioactive compounds that exhibit antibacterial activity against pathogens. Both phenolic extracts and essential oils are bacteriostatic against several bacteria. The main individual antibacterial phenolic compounds in Scots pine are pinosylvins that effectively inhibit growth of pathogens such as Bacillus cereus, Staphylococcus aureus and Listeria monocytogenes. From other phenolic compounds lignans appeared to be the least bacteriostatic and flavonoids tend to occur as glycosylated forms which have lower antibacterial activity than their aglycones. Gram-positive bacteria are generally more susceptible to plants bioactive compounds than gram-negative bacteria.

Three types of symbiotic mayonnaise sauces, with free, encapsulated bacteria with calcium alginate (in 4% concentration) and encapsulated with calcium alginate and resistant starch by two strains of L. acidophilus and L. casei were manufactured in triplicate under the same conditions. The numbers of viable cells, pH, acidity and rheological properties’ of symbiotic mayonnaise samples during 91 days of storage in refrigerated (4°C) conditions was evaluated. It was observed that the number of viable cells of Lactobacillus acidophilus and L. casei was reduced significantly (p<0.05) from day 1 to day 91 of storage period in Free State comparing encapsulated bacteria in both type of them. Reduction of viable cells encapsulated with Hi maize-alginate had a slower rate than probiotic cells encapsulated with calcium alginate (4%) in both L. acidophilus and L. casei mayonnaise samples container types. About changing in pH and increasing acidity of symbiotic mayonnaise sauces, the samples containing free probiotic cells had the highest changing and samples inoculated encapsulated cells with Hi maize-alginate mixture had lowest changing in these factors between all sample types. Also there weren’t any significant changes in rheological properties of encapsulated symbiotic mayonnaise sample compared with control samples but in samples containing free cells a significant differences compared with control samples were seen. Finally, proved microencapsulation could help survival probiotic cells enough in therapeutic effects on consumers at the end of storage and modification encapsulation with adding Hi maize starch to calcium alginate improved preserving chemical qualities of symbiotic mayonnaise sauce.cells enough in therapeutic effects on consumers at the end of storage and modification encapsulation with adding Hi maize starch to calcium alginate improved preserving chemical qualities of symbiotic mayonnaise sauce.

In conventional fed batch process development approaches, batch operating parameters (such as pH, temperature, seeding density, dissolved oxygen concentration) are kept constant and only feeding parameters such as feeding time, post-feed concentration are manipulated. The batch and fed batch operating parameters are assumed to be independent of each other. This approach to process development ignores any interactions that might exist between the batch and fed-batch operating parameters are therefore not evaluated. However in a complex bioprocess, none of the factors affecting the process can be assumed to be independent of each other and mutually exclusive. Therefore in this study an attempt was made to study the interaction between fed-batch operating parameter-post feed glucose concentration (A) and batch operating parameters- seeding density (B), temperature (C), and dissolved oxygen concentration (D) by their simultaneous manipulation, as well as the effect of these interactions on cell growth and monoclonal antibody (mAb) production. NS0 cell line producing the mAb’s against carcino-embryogenic antigen (Anti-CEA) was used. The final mAb concentration, viable cell density and integral of viable cell concentration (IVCC) were the responses evaluated. Statistical analysis experimental data showed that parameter (A) and its interaction with parameter (B) were the main factors affecting both the response variables. In comparison to the batch run which yielded 5.21 mg/L mAb, the developed fed batch process increased the mAb titer by 10 fold (59.40 mg/mL), and the IVCC was increased by 7 fold. The maximum VCD value (3.46×106 cells/mL) of the developed fed batch process was 1.25 over fold the value for batch.

Role of Mitochondrial Carriers in Metabolic Engineering