Desulfurization of Model Oil Containing Dibenzothiophene or 4,6-Dimethyl Dibenzothiophene by Alginate Immobilized Cells

2011 ◽  
Vol 233-235 ◽  
pp. 1171-1176
Author(s):  
Ming Fang Luo ◽  
Hui Zhou Liu
Keyword(s):  
Immobilized Cells ◽  
Resting Cells ◽  
Negative Bacterium ◽  
Simple Method ◽  
Alginate Gel ◽  
The Stability ◽  
Model Oil ◽  
Pseudomonas Delafieldii ◽  
Ca Alginate ◽  
Desulfurization Activity

Gram-negative bacterium, Pseudomonas delafieldii R-8 (CGMCC 0570) is capable of desulfurizing dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) to produce corresponding monohydroxydimethylbiphenyl. The immobilization of the resting cells of this strain in Ca-alginate gel effectively improved the stability of the cells and the desulfurization ability per amount of cells. 1 mmol/L of DBT and 4,6-DMDBT could be completely degraded in about 1 d. About 39 percent of the activity for 4,6-DMDBT was recovered after immobilization. The desulfurization activity was increased with the decrease of the diameter of the beads. The Ca-alginate immobilized cells could be used repeatedly for over 190 h with the addition of calcium ions to strengthen them. A thin layer of hydrophobic polyurea was coated on the surface of Ca-alginate gel using a simple method. The desulfurization activity was enhanced after the coating.

Flocculation of Pseudomonas delafieldii R-8 by γ-Polyglutamic Acid Combined with Celite for Biodesulfurization of Model Oil

2013 ◽  
Vol 726-731 ◽  
pp. 368-372
Author(s):  
Fei Yan Zhu ◽  
Zhong Bo Hu
Keyword(s):  
Immobilized Cells ◽  
Polyglutamic Acid ◽  
Desulfurization Rate ◽  
Model Oil ◽  
Pseudomonas Delafieldii ◽  
Desulfurization Activity

γ-polyglutamic acid (PGA) was firstly used for recovery and immobilization of Pseudomonas delafieldii R-8 cells in biodesulfurization process. The PGA mediated flocculation was combined with celite adsorption to immobilize R-8 cells and the as-prepared immobilized cells showed a high initial specific desulfurization rate at 0.243 mmol l-1 h-1 and a good desulfurization stability with 95% desulfurization activity remained after 6 batches of desulfurization processes.

Palatinose production by free and Ca-alginate gel immobilized cells of Erwinia sp.

2007 ◽  
Vol 36 (3) ◽  
pp. 202-208 ◽  
Author(s):  
Haroldo Yukio Kawaguti ◽  
Hélia Harumi Sato
Keyword(s):  
Immobilized Cells ◽  
Alginate Gel ◽  
Ca Alginate

Soil Strength Reduction Method Induced by Variation of Water Content

2012 ◽  
Vol 170-173 ◽  
pp. 847-852
Author(s):  
Peng Ming Jiang ◽  
Zhong Lei Yan ◽  
Peng Li
Keyword(s):  
Slope Stability ◽  
Unsaturated Soil ◽  
Unsaturated Soils ◽  
Characteristic Curve ◽  
Strength Reduction ◽  
Actual State ◽  
Soil Slope ◽  
Simple Method ◽  
The Common ◽  
The Stability

As the complexity of unsaturated soil theory, and it must have a long test period when we study the unsaturated soils, so the conventional design analysis software does not provide such analysis, so we can imagine that such a slope stability analysis does not accurately reflect the actual state of the slope. Based on the known soil moisture content，this paper use the soil water characteristic curve and strength theory of unsaturated soil to calculate the strength reduction parameters of soil which can calculate the stability of the soil slope when using the common calculation method. It is noticeable that this method can be extended and applied if we establish regional databases for this simple method, and these databases can improve the accuracy of the calculation of slope stability.

Use of Immobilized Candida Cells on Xylitol Production from Sugarcane Bagasse

2000 ◽  
Vol 55 (3-4) ◽  
pp. 213-217 ◽  
Author(s):  
Walter de Carvalho ◽  
Silvio Silvério da Silva ◽  
Michele Vitolo ◽  
Ismael Maciel de Mancilha
Keyword(s):  
Sugarcane Bagasse ◽  
Immobilized Cells ◽  
Alginate Beads ◽  
Candida Guilliermondii ◽  
Volumetric Productivity ◽  
Xylitol Production ◽  
Experimental Conditions ◽  
Work Volume ◽  
Yield Factor ◽  
Ca Alginate

Abstract In this study we used the yeast Candida guilliermondii FTI 20037 immobilized by entrapment in Ca-alginate beads (2 .5 -3 mm diameter) for xylitol production from concentrated sugarcane bagasse hemicellulosic hydrolysate in a repeated batch system. The fermentation runs were carried out in 125- and 250-ml Erlenmeyer flasks placed in an orbital shaker at 30 °C and 200 rpm during 72 h, keeping constant the proportion between work volume and flask total volume. According to the results, cell viability was substantially high (98%) in all fermentative cycles. The values of parameters xylitol yield and volumetric productivity increased significantly with the reutilization of the immobilized biocatalysts. The highest values of xylitol final concentration (11.05 g/1), yield factor (0.47 gig) and volumetric productivity (0.22 g/lh) were obtained in 250-ml Erlenmeyer flasks containing 80 ml of medium plus 20 mi of immobilized biocatalysts. The support used in this study (Ca-alginate) presented stability in the experimental conditions used. The results show that the use of immobilized cells is a promising approach for increasing the xylitol production rates.

scholarly journals Degradation of chlorobenzene and 2-chlorotoluene by immobilized bacteria strains Comamonas testosterone kt5 and Bacillus subtilis dkt

2019 ◽  
Vol 41 (4) ◽  
Author(s):  
Ha Danh Duc ◽  
Nguyen Thi Oanh
Keyword(s):  
Bacillus Subtilis ◽  
Bacterial Strain ◽  
Immobilized Cells ◽  
Resting Cells ◽  
Long Term Storage ◽  
Degradation Rates ◽  
Contributory Negligence ◽  
Biofilm Bacteria ◽  
Term Storage

Chlorobenzenes and chlorotoluenes have been used to produce a number of industrial products. They are toxic and widely detected in environments due to human contributory negligence. In this article, the mixed culture of a toluenes-degrading bacterial strain, Comamonas testosterone KT5 (a Gram-positive, catalase-positive bacterium) and a chlorobenzenes-degrading bacterial strain, Bacillus subtilis DKT (a Gram-negative soil bacterium) effectively degraded both chemical compounds co-contaminating in liquid media. In addition, the degradations of mixed compounds by biofilm, bacteria immobilized in polyurethane foam (PUF) and alginate were determined. The results showed that the degradation of both compounds by cells in alginate was significantly higher than that by suspended cells. Moreover, cells immobilized in these materials showed lower adverse effects than those of non-immobilized cells for long-term storage. For examples, the degradation rates for chlorobenzine and 2-chlorotoluene by resting cells reduced by 39.5% and 37.3% after storage for 4 months at 4°C, while the degradation rates by immobilized cells decreased by from 16.3% to 19.8% respectively. 

Semicontinuous and Continuous Production of Citric Acid with Immobilized Cells of Aspergillus niger

1987 ◽  
Vol 42 (4) ◽  
pp. 408-413 ◽  
Author(s):  
H. Eikmeier ◽  
H. J. Rehm
Keyword(s):  
Citric Acid ◽  
Aspergillus Niger ◽  
Immobilized Cells ◽  
Continuous Production ◽  
Continuous Process ◽  
Batch Experiments ◽  
Medium Exchange ◽  
Free Cells ◽  
Semicontinuous Cultivation ◽  
Ca Alginate

Abstract The citric acid excretion of Ca-alginate-immobilized cells of Aspergillus niger in batch culture decreased with a half-time of approximately 19 days. Reactivation of the biocatalysts by regeneration in growth medium was possible, but it was followed by a submerged sporulation of the fungus, and medium was highly contaminated with free cells. Citric acid production could better be prolonged by semicontinuous cultivation with medium exchange every 7 or 14 days, respectively. After 32 days the remaining activity in semicontinuous culture was 1.4-fold higher than in comparable batch experiments. Similar improvements were obtained with a continuous process at a dilution rate of 0.125 v/v · d, whereby medium efflux completely free of detaching mycelia.

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