leila Ardestani; Morteza Hosseini; Mohsen Jahanshahi; Alireza Amiri
Abstract
The bioactive compounds in extracts are prone to degradation by oxidation, heat, or light. Nanoencapsulation is one of the best techniques to keep the properties of these chemical compounds. The aim of this study was the extraction of Melissa officinalis (MO) and nanoencapsulation of the extract via ...
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The bioactive compounds in extracts are prone to degradation by oxidation, heat, or light. Nanoencapsulation is one of the best techniques to keep the properties of these chemical compounds. The aim of this study was the extraction of Melissa officinalis (MO) and nanoencapsulation of the extract via chitosan as a biodegradable polymer. In this research, extraction of MO was investigated using various extraction methods and nanoencapsulation with MO extract was carried out via ionic gelation technique. The effectiveness of the extracts was evaluated by measuring the total phenolic content (TPC), antioxidant activity, and extraction efficiency of the solid contents. The highest efficiency was achieved for microwave-assisted extraction with the utmost values in each parameter. (TSC) was 22.81% and amounts of the TPC and antioxidant activity were 311.94 mg Gallic acid and 36 mg diphenyl picryl hydrazyl (DPPH) per 1g of the plant, respectively. Morphology study by field emission scanning electron microscopy (FE-SEM) indicated spherical shape nanoparticles with a diameter of 25nm. The size of the nanoparticles was evaluated by the Dynamic Light Scattering (DLS) technique for various concentrations of the used extracts in the encapsulation process. For 1.0, 3.0, and 5.0 mg /mL concentration, mean diameters were 24, 118, and 145 nm, respectively. Results indicated that microwave-assisted extraction was the best extraction method for MO and the encapsulation of MO extract could be created successfully with different particle sizes for the protection of bioactive compounds. Since MO is a beneficial herbal plant, the development of this research is recommended.
Rouhollah Hedayati; Morteza Hosseini; Ghasem Najafpour; Hosein Attar
Abstract
Cobalamins are one of the most complicated cofactors produced by the microorganisms. Propionibacterium freudenreichii has to follow the anaerobic and aerobic conditions respectively during a course of batch fermentation, for the production of the biologically active form of cobalamins. Magnetite (Fe3O4) ...
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Cobalamins are one of the most complicated cofactors produced by the microorganisms. Propionibacterium freudenreichii has to follow the anaerobic and aerobic conditions respectively during a course of batch fermentation, for the production of the biologically active form of cobalamins. Magnetite (Fe3O4) nanoparticles can modify gas-liquid volumetric mass transfer coefficient in the fermentation system to create more efficient aeration step. Initially, the modified production of Fe3O4 nanoparticle through coprecipitation method was investigated, and the smallest size of nanoparticles optimized to 13.86 nm via Box-Behnken design of response to surface methodology (RSM). The optimum condition was at the synthesis temperature of 60 °C, reaction duration of 10 minutes, and the medium agitation speed of 700 rpm. Synthesized nanoparticles characterized by SEM images, PXRD and EDS analysis while EDS spectrum reflects 39.33% of Fe and 51.8% of oxygen atomic distribution, which confirms Fe3O4 nanoparticles synthesis. Magnetite nanoparticle suspension added to the fermentation medium to compare the effect of nanoparticles incorporation and dimethylbenzimidazole addition on the cobalamin production via Propionibacterium freudenreichii. NPs incorporation in the fermentation broth was able to increase cyanocobalamin production by 20%, while there was no incorporation of external DMBI in the medium. Finally, by the central composite design analysis, cyanocobalamin production from Propionibacterium freudenreichii fermentation was optimized to 1.548 mg.L-1. Oily sludge (as a new carbon source) of 4 %w/v, magnetite nanoparticles suspension of 7.5 %v/v, and the fermentation temperature of 37 °C caused to CCD optimum condition.