Inhibiting Smooth Muscle Cell Proliferation via Immobilization of Heparin/Fibronectin Complexes on Titanium Surfaces

The aim of this study was to investigate the inhibitory effect of heparin/fibronectin （Hep/Fn） complexes on neointimal hyperplasia following endovascular intervention. Hep/Fn complexes were immobilized onto titanium （Ti） surfaces, with subsequent X-ray photoelectron spectroscopy （XPS）, Toluidine Blue 0 （TBO） and immunohistochemistry methods were used to characterize surface properties. Smooth muscle cell （SMC） cultures were used to evaluate the effect of Hep/Fn complexes on SMC proliferation. Results showed that Hep/Fn complexes successfully immobilized onto Ti surfaces and resulted in an inhibition of SMC proliferation. This study suggests that Hep/Fn surface-immobilized biomaterials develop as a new generation of biomaterials to prevent neointimal hyperplasia, particularly for use in cardiovascular implants.

Comparison of Di-n-methyl Phthalate Biodegradation by Free and Immobilized Microbial Cells

To compare the biodegradation of di-n-methyl pathalate by free and immobilized microbial cells. Methods The enrichment and isolation technique was used to isolate the microorganism. The PAV-entrapment method was utilized to immobilize the microorganisms. The scanning electron microscophy (SEM) was used to observe the growth and distribution of microbial cells immobilized inside the PVA bead gels. The GC/MS method was used to identify the main intermediates of DMP degradation. Results The microbial cells could grow quite well in PVA gel. The metabolic pathway did not change before and after immobilization of the microbial cells. The degradation rate of immobilized cells was higher than that of free cells. Conclusion The immobilized microbial cells possess advantages than free cells when applied to the biodegradation of toxic organic pollutants.

Decolourization of Reactive Brilliant Blue KN-R by immobilized cells of Aspergillus ficuum

Aspergillus ficuum was immobilized with sodium alginate, and decolourization of Reactive Brilliant Blue KN-R was studied on immobilized and free Aspergillus ficuum. The optimal preparation condition of the strain immobilization was obtained by the orthogonal test, it is sodium alginate 3%, CaCl_2 5%, wet mycelia 30 g/L, calcific time 8 h. It was found that the immobilized cells could effectively decolourize Reactive Brilliant Blue KN-R, the optimum temperature and pH were 33℃ and 5.0, respectively. The kinetics study of decolourization of immobilized cells showed that the decolourization of Aspergillus ficuum immobilized conformed to zero-order reaction model. The decolourization efficiency of immobilized cell compared with that of free cell in different physical conditions. Results showed that the decolourization of immobilized cells with mycelia had the best efficiency. The immobilized cells could be reused after the first decolourization.

Enzymatic Synthesis of Agmatine by Immobilized Escherichia coli Cells with Arginine Decarboxylase Activity

A new method for the enzymatic synthesis of agmatine by immobilized Escherichia coli cells with arginine decarboxylase（ADC） activity was established and a series of optimal reaction conditions was set down. The arginine decarboxylase showed the maximum activity when the pyridoxal phosphate（PLP） concentration was 50 mmol/L, pH=7 and 45 °C. The arginine decarboxylase exhibited the maximum production efficiency when the substrate concentration was 100 mmol/L and the reaction time was 15 h. It was also observed that the appropriate concentration of Mg2＋, especially at 0.5 mmol/L promoted the arginine decarboxylase activity; Mn2＋ had little effect on the arginine decarboxylase activity. The inhibition of Cu2＋ and Zn2＋ to the arginine decarboxylase activity was significant. The immobilized cells were continuously used 6 times and the average conversion rate during the six-time usage was 55.6%. The immobilized cells exhibited favourable operational stability. After optimization, the maximally cumulative amount of agmatine could be up to 20 g/L. In addition, this method can also catalyze D,L-arginine to agmatine, leaving the pure optically D-arginine simultaneously. The method has a very important guiding significance to the enzymatic preparation of agmatine.

Rational design of Aspergillus flavus A5p1-immobilized cell system to enhance the decolorization of reactive blue 4(RB4)

Anthraquinone dyes are a class of typical carcinogenic and hard-biodegradable organic pollutants.This study aimed to enhance the decolorization of anthraquinone dye by rationally designing an expected immobilized system.Reactive blue 4(RB4) was used as a substrate model and a previous isolated dyedegrading strain Aspergillus flavus A5pl was purposefully immobilized.Considering the effects of cell attachment and mass transfer,the polyurethane foam(PUF) with open pore structure was selected as the immobilization carrier.Results showed that the RB4 decolorization efficiency was significant enhanced after immobilization.Compared to the free mycelium system,the decolorization time of200 mg·L^(-1)RB4 was shortened from 48 h to 28 h by the PUF-immobilized cell system.Moreover,the PUF-immobilized system could tolerate RB4 up to 2000 mg-L^(-1).In the packed bed bioreactor(PBBR),an average decolorization efficiency of 93.3% could be maintained by the PUF-immobilized system for26 days.The decolorization process of RB4 was well described by the logistic equation and the degradation pathway was discussed.It was found that the higher specific growth rate of the PUF-immobilized cells was one of reasons for the enhanced decolorization.The good performance of the PUFimmobilized cell system would make it have potential application value for RB4 bioremediation.

Batch CGTase Production with Free and Immobilized <i>Bacillus firmus</i>Strain 37 in Bovine Bone Charcoal

The present study aimed to study the batch production of CGTase (cyclomaltodextrin-glucanotransferase) with Bacillus firmus strain 37 free and immobilized in bovine bone charcoal in batch mode and in a fluidized bed batch reactor, respectively. The bovine bone charcoal is an innovative support material for the immobilization of microorganisms’ producers of enzymes and the use of this microbial support allows its reuse to a significant cost reduction of the process. The batch fermentation with free cells was investigated for 96 h and reached a CGTase activity equal to 0.77 U/mL. When the microorganism was immobilized on bovine bone charcoal (7 g) and cultivated in fluidized bed batch reactor with air supplementation (1 volume of air/volume of medium * minute), the same activity could be achieved in 24 h. The results of enzymatic activity achieved show the potential of CGTase production in a short time with Bacillus firmus strain 37 immobilized in bovine bone charcoal matrix and using air supplementation in the production medium.

Improved Method for Lacosamide Synthesis with Chemoenzymatic Method

Lacosamide was prepared by chemical method coupled with enzymatic method. N-Acetyl-D, L-3-methoxy-alanine, derived from D,L-3-methoxy-alanine, was used in the resolution process catalyzed by immobilized Escherichia coli cells with aminoacylase（EC3.5.1.14） activity. N-Acetyl-D-3-methoxy-alanine and L-3- methoxy-alanine were obtained from the resolution system. Lacosamide was synthesized by the amidation of N-acetyl-D-3-methoxy-alanine with benzylamine.

Asymmetric Reduction of 3,5-Bistrifluoromethyl Acetophenone with NADH Regeneration by Immobilized Cells of Saccharomyces rhodotorula in Aqueous-Organic Solvent Biphasic System

Asymmetric reduction of 3,5-bistrifluoromethyl acetophenone to produce(S)-3,5-bistrifluoromethylphenyl ethanol was successfully carried out with sodium alginate immobilized Saccharomyces rhodotorula cells in an aqueous-organic solvent biphasic system.The possible influential factors were examined thoroughly according to their effects on conversion rate and e.e of the product.Organic solvents were rated by their biocompatibility and conversion potential.The immobilized cells [125 mg/mL in 20 mmol/L Tris-HCl buffer and 5%(j) octane at pH 8] showed the best conversion with a substrate concentration of 1.42 g/L at 30℃ with glucose as co-substrate for cofactor regeneration.Sequential 8-batch process was carried out with immobilized cells with a slow decrease in conversion and e.e.The immobilized cells showed stable catalytic activity with 50% reserved activity and are superior especially in reusability in comparison with resting cells.

An innovative approach to minimize excess sludge production in sewage treatment using integrated bioreactors

The present investigation deals with an application of integrated sequential oxic and anoxic bioreactor（SOABR） and fluidized immobilized cell carbon oxidation（FICCO） reactor for the treatment of domestic wastewater with minimum sludge generation. The performance of integrated SOABR-FICCO system was evaluated on treating the domestic wastewater at hydraulic retention time（HRT） of 3 hr and 6 hr for 120 days at organic loading rate（OLR）of 191 ± 31 mg/（L·hr）. The influent wastewater was characterized by chemical oxygen demand（COD） 573 ± 93 mg/L; biochemical oxygen demand（BOD5） 197 ± 35 mg/L and total suspended solids（TSS） 450 ± 136 mg/L. The integrated SOABR-FICCO reactors have established a significant removal of COD by 94% ± 1%, BOD5 by 95% ± 0.6% and TSS by 95% ± 4% with treated domestic wastewater characteristics COD 33 ± 5 mg/L; BOD59 ± 0.8 mg/L and TSS 17 ± 9 mg/L under continuous mode of operation for 120 days. The mass of dry sludge generated from SOABR-FICCO system was 22.9 g/m3. The sludge volume index of sludge formed in the SOABR reactor was 32 mL/g and in FICCO reactor it was 46 mL/g. The sludge formed in SOABR and FICCO reactor was characterized by TGA, DSC and SEM analysis. Overall, the results demonstrated that the integrated SOABR-FICCO reactors substantially removed the pollution parameters from domestic wastewater with minimum sludge production.

Preliminary study of groundwater denitrification using a composite membrane bioreactor

A composite membrane bioreactor(CMBR)integrating the immobilized cell technique and the membrane separation technology was developed for groundwater denitrification.The CMBR had two well mixed compartments with one filled with the nitratecontaining influent and the other with a dilute ethanol solution;the compartments were separated by the composite membrane consisting of a microporous membrane facing the influent and an immobilized cell membrane facing the ethanol solution.Nitrate and ethanol molecules diffused from the respective compartments into the immobilized cell membrane where nitrate was reduced to gaseous nitrogen by the denitrifying bacteria present there with ethanol as the carbon source.The microporous membrane was attached to one side of the immobilized cell membrane for retention of the disaggregated bacteria.Relative to the single dose of external ethanol,the twodose supplementation produced better treatment results as evidenced by the lower concentrations of NO_(3)^(-)-N and ethanol(as measured by total organic carbon)of the effluent.The batch treatment in CMBR removed most of the nitrate in the influent and attained a stable denitrification rate of 0.1 g·m^(-2)·h^(-1)for most of the 96-h cycles during the 30-cycle study.The effluent was essentially free of ethanol and nitrite nitrogen.