Influence of alcohol treatments on the activity of lipases immobilized on methyl-modified silica aerogels.

The effects of alcohol treatment on the activity and loading amount of Candida rugosa lipase (CRL), Candida Antarctica lipase B (CALB) and Porcine Pancreas lipase (PPL) immobilized on methyl-modified silica aerogels were investigated, and the fluorescent analysis was used to explore the change of lipase hydrophobicity in aqueous solution caused by alcohols. It is found that alcohol types and the stages at which alcohol was added significantly influenced the performance of immobilized lipases through changing the hydrophobicity of the molecules. For CRL and PPL, five kinds of alcohol were added in the adsorption process, and n-butanol and isopropanol improved the apparent activity of CRL and PPL up to 2.

Effect of pore diameter and cross-linking method on the immobilization efficiency of Candida rugosa lipase in SBA-15.

The influences of pore diameter and cross-linking method on the immobilization efficiency of Candida rugosa lipase (CRL) in a mesoporous material have been investigated. Five kinds of SBA-15 with different pore-sizes (6.8nm, 9.

Effect of solvents and precipitant on the properties of chitosan nanoparticles in a water-in-oil microemulsion and its lipase immobilization performance.

When chitosan nanoparticles were prepared in a water-in-oil (W/O) microemulsion by using 2% (wt) acetic acid (HAc) and 30% (wt) tri-n-octylamine (TOA) as solvent and precipitant, respectively, particle diameters of 7 nm were observed and the particles formed ovoid shaped aggregates. Using 0.05% HCl and 5.

In situ preparation of magnetic Fe3O4-chitosan nanoparticles for lipase immobilization by cross-linking and oxidation in aqueous solution.

A new and simple method has been proposed to prepare magnetic Fe(3)O(4)-chitosan (CS) nanoparticles by cross-linking with sodium tripolyphosphate (TPP), precipitation with NaOH and oxidation with O(2) in hydrochloric acid aqueous phase containing CS and Fe(OH)(2), and these magnetic CS nanoparticles were used to immobilize lipase. The effects on the sequence of adding NaOH and TPP, the reaction temperature, and the ratio of CS/Fe(OH)(2) were studied. TEM showed that the diameter of composite nanoparticles was about 80 nm, and that the magnetic Fe(3)O(4) nanoparticles with a diameter of 20 nm were evenly dispersed in the CS materials.

Immobilization of lipase on methyl-modified silica aerogels by physical adsorption.

In this work, methyl-modified silica aerogels, a new kind of macro-porous material with high porosity, were used as carriers to immobilize lipase by adsorption. SEM, TEM, nitrogen adsorption device, and thermogravimetric analysis were used to characterize the properties of modified aerogels. The surface area was 395.

Adsorption of bovin serum albumin (BSA) onto the magnetic chitosan nanoparticles prepared by a microemulsion system.

The adsorption characteristics of BSA onto the magnetic chitosan nanoparticles have been investigated in this paper. The magnetic chitosan nanoparticles were prepared by adding the basic precipitant of NaOH solution into a W/O microemulsion system. The morphology of magnetic chitosan nanoparticles was observed by transmission electron microscope (TEM).

Immobilization of lipase by ultrafiltration and cross-linking onto the polysulfone membrane surface.

In this study, a biphasic enzymatic membrane reactor was made by immobilizing Candida Rugosa lipase onto the dense surface of polysulfone ultrafiltration membrane by filtration and then cross-linking with glutaraldehyde solution. The reactor was further applied for the hydrolysis of olive oil, the performance of which was evaluated in respect of apparent reaction rate based on the amount of fatty acids extracted into the aqueous phase per minute and per membrane surface. It was found that the ultrafiltration and cross-linking process greatly improved the reaction rate per unit membrane area and the enzyme lifetime.

[Pretreatment and resource utilization of industrial effluent with benzoic acid].

Extraction equilibrium of benzoic acid were studied using 20%, 30% and 50% tributyl phosphate (TBP) in kerosene, 1-octanol and toluene as the extractants, to investigate the efficient method of recovering benzoic and acetic acid in the industrial effluent and meeting the requirement of the terminal wastewater treatment. The CODCr value in residual phase and the recovery of benzoic acid in various extractants were measured. The results showed that the recovery of benzoic acid was closed to 100% with 50% TBP/kerosene system, and depended on the polarity of extractant for pure solvent system.

[Mass transfer model of membrane extraction for recovery of cadmium ion and zinc ion].

By measuring the residence time distribution (RTD) curve of shell side and tube side of hollow fiber modules, it was found that the flow status in hollow fiber module with moderate or low packing density was complicated. For tube side, there were deviation between the experimental RTD curves and the theoretical laminar flow ones, which indicated that the flow status in tube side was between laminar flow and turbulent flow. For shell side, the experimental RTD curves agreed well with the laminar flow ones.