ABSTRACT
In recent years, functional foods with lipophilic nutraceutical ingredients are gaining more and more attention because of its potential healthy and commercial value, and developing of various bioderived food-grade particles for use in fabrication of Pickering emulsion has attracted great attentions. Herein, the bio-originated sodium caseinate-lysozyme (Cas-Lyz) complex particles were firstly designed to be used as a novel interfacial emulsifier for Pickering emulsions. Pickering emulsions of various food oils were all successfully stabilized by the Cas-Lyz particles without addition of any synthetic surfactants, while the fluorescence microscopy and SEM characterizations clearly evidenced Cas-Lyz particles were attached on the surface of emulsion droplets. Additionally, the Cas-Lyz particles stabilized emulsion can also be used to encapsulate the ß-carotene-loaded soybean oil, suggestion a potential method to carry lipophilic bioactive ingredients in an aqueous formulation for food, cosmetic and medical industry. At last, we present a Pickering emulsion strategy that utilizes biocompatible, edible and body temperature-responsive lard oil as the core material in microcapsules, which can achieve hermetic sealing and physiological temperature-triggered release of model nutraceutical ingredient (ß-carotene).
Subject(s)
Capsules , Emulsions , Temperature , beta Carotene , beta Carotene/chemistry , Emulsions/chemistry , Drug Liberation , Caseins/chemistryABSTRACT
With the rapid science and technology advancement, the oil-water separation in oily wastewater has become an urgent problem, especially the emulsified oil-water mixtures. Hollow carbon spheres (HCSs) have tremendous potential in separating oil-water emulsions due to their rich porous channels and high surface-to-volume ratio. In this work, as-prepared chitosan/poly(γ-glutamic acid) nanoparticles crosslinked by Ni2+ (Ni2+/CS/γ-PGA NPs) were used as carbon precursor to fabricate HCSs. This strategy separated the formation process of the biomolecular microspheres and the carbonization process. Especially, the Ni2+/CS/γ-PGA NPs were fabricated from the self-assembly of chitosan and γ-PGA in aqueous solution and the crosslinking of Ni2+ via the electrostatic interactions, facilitating the formation of biomolecular microspheres and making the usable of biomolecule-based carbon precursors diversity. After lyophilization, Ni2+/CS/γ-PGA NPs powder was obtained, which was then carbonized in a tube furnace under N2 atmosphere. During the carbonization process, the nickel species aggregated together to form the core of nickel@carbon nanoparticles, and carbon formed the shell. At last, nickel nanoparticles were removed from the carbon framework by hydrochloric acid, obtaining HCSs with super-hydrophobicity and lipophilicity. The as-prepared HCSs exhibited excellent separation performance in oil-in-water emulsions.
Subject(s)
Chitosan , Nanoparticles , Emulsions , Carbon , Nickel , WaterABSTRACT
Dextran (Dex) and poly(ethylene glycol) (PEG)-based aqueous emulsions were stabilized using the self-assembled chitosan colloidal particles (CS CPs). Besides, the effects of pH, CS CPs concentration, polymer concentration, volume ratio of PEG solution to Dex solution, temperature, homogenizing speed and homogenizing time on the property of the W/W emulsions were investigated, respectively. In order to enhance the stability of the PEG-Dex emulsion, sodium tripolyphosphate was used to cross-link the CS CPs at the interface of emulsion droplets, which resulted in the stability duration for >1 year. Finally, the CS CPs were used as a support to immobilize urease and bovine serum albumin and a stabilizer to prepare W/W emulsion, which were then adopted as a catalysis system and as a spinning solution to fabricate drug-loaded nanofiber. This strategy potentially provides a new opportunity to encapsulate the active molecules at the water-water interface, and enrich the types of usable active molecules in the encapsulation in the W/W emulsions.
ABSTRACT
As a native CoQ10 producer, Rhodobacter sphaeroides has been extensively engineered to enhance CoQ10 production. However, the genetic manipulations using plasmids suffer from risk of plasmid loss during propagation process, biomass impairment due to cellular burden and bio-safety concerns. In this paper, genomic manipulations via Tn7 transposition was conducted to boost the CoQ10 biosynthesis in R. sphaeroides. The titer production and content of CoQ10 were improved by 18.44% and 18.87%, respectively compared to the wild type, when an additional copy of dxs and dxr were integrated into the genome. Further overexpression of idi and ispD by genomic integration created strain RSPCDDII with CoQ10 production and content of 81.23 mg/L and 5.93 mg/g, which were 54.28 and 55.97% higher than those of the wild type. The gene segments were successfully inserted into the attTn7 site of the R. sphaeroides genome. Meanwhile, the biomass was not affected. Compared to overexpression of genes on plasmids, this strategy could enhance protein expression to a proper level without affecting cell growth, and in a more stable manner.
Subject(s)
Rhodobacter sphaeroides , Biomass , Genomics , Rhodobacter sphaeroides/genetics , Ubiquinone/analogs & derivativesABSTRACT
A molecularly imprinted biosensor for lysozyme based on the polymer nanoparticles self-assembled from water-soluble and electroactive poly (γ-glutamic acid) modified with 3-aminothiophene copolymer were prepared. The water-soluble copolymer made imprinting of lysozyme in aqueous solution possible and thus facilitated improvement of the activity of LYS. Subsequent electro-polymerization not only locked the recognition site between copolymer and lysozyme but also created a conductive polymer network, which can enhance the electron transfer rate and increase the conductivity of the film. The prepared molecularly imprinted biosensor exhibited a wide linear range from 1 × 10-10 to 1 × 10-5 mg mL-1, and satisfactory selectivity, stability, repeatability for lysozyme detection.
