Immobilization Of Microbial Cells Research Articles

Influence of phenol on the biodegradation of pyridine by freely suspended and immobilized Pseudomonas putida MK1

To study the effect of co-contaminants (phenol) on the biodegradation of pyridine by freely suspended and calcium alginate immobilized bacteria. Varying concentrations of phenol were added to free and calcium alginate immobilized Pseudomonas putida MK1 (KCTC 12283) to examine the effect of this pollutant on pyridine degradation. When the concentration of phenol reached 0.38 g l(-1), pyridine degradation by freely suspended bacteria was inhibited. The increased inhibition with the higher phenol levels was apparent in increased lag times. Pyridine degradation was essentially completely inhibited at 0.5 g l(-1) phenol. However, immobilized cells showed tolerance against 0.5 g l(-1) phenol and pyridine degradation by immobilized cell could be achieved. This works shows that calcium alginate immobilization of microbial cells can effectively increase the tolerance of P. putida MK1 to phenol and results in increased degradation of pyridine. Treatment of wastewater stream can be negatively affected by the presence of co-pollutants. This work demonstrates the potential of calcium alginate immobilization of microbes to protect cells against compound toxicity resulting in an increase in pollutant degradation.

Biodegradation and Decolorization of Pulp and Paper Mill Effluent by Anaerobic and Aerobic Microorganisms in a Sequential Bioreactor

Paecilomyces sp. and Pseudomonas syringae pv myricae (CSA105) were isolated from sediment core of drainage of the pulp and paper mill industry. Fungi and bacteria were applied for treatment of pulp and paper mill effluent in a two-step and three-step fixed film sequential bioreactor containing sand and gravel at the bottom of the reactor for immobilization of microbial cells. Degradation of chlorinated phenols and formation of their metabolites were determined by high performance liquid chromatography. The microbes exhibited significant reduction in colour (88.5%), lignin (79.5%), chemical oxygen demand (87.2%) and phenol (87.7%) in two-step aerobic sequential bioreactor, and colour (87.7%), lignin (76.5%), chemical oxygen demand (83.9%) and phenol (87.2%) in three-step anaerobic-aerobic sequential bioreactor.

A porous microcapsule membrane with straight pores for the immobilization of microbial cells

A novel type of polyethersulfone porous microcapsule membranes with straight pores across the whole thickness was successfully prepared with a gel–sol phase inversion method for the immobilization of microbial cells. The mean diameter of the microcapsules was about 2 mm, and the microcapsule membranes were full of straight finger pores. The pore size distribution was from 3.5 to 53.6 μm and the median pore diameter was 13.6 μm. The prepared microcapsules had large total pore volume, and total pore area and porosity (as large as 91.7%). The prepared porous microcapsules were used as carriers for the immobilization of microbial cells in the anaerobic wastewater biotreatment process. Immobilized anaerobic microbial cells were found both inside the membrane pores and in the inner spaces of microcapsules. The prepared porous microcapsules were proven to be efficient for the microbial immobilization under anaerobic conditions.

Biodegradation of 2,4-dichlorophenol in an air-lift honeycomb-like ceramic reactor

A novel air-lift bioreactor, with a honeycomb-like ceramic column packed in the inner draft tube as the carrier for immobilization of microbial cells, was developed in this laboratory. A microorganism, identified as Achromobacter sp. and capable of degrading 2,4-dichlorophenol (2,4-DCP), was immobilized in the ceramic carrier and used for biodegradation of 2,4-DCP. Semi-continuous biodegradation of 2,4-DCP as a single substrate and in the presence of phenol as co-substrate was investigated. The results showed that when 2,4-DCP occurs alone, its biodegradation rate increased gradually from Run 1 to Run 6 and the degradation process could be described with zero-order kinetics model. When phenol was used as co-substrate, the existence of phenol could inhibit the biodegradation of 2,4-DCP and the biodegradation rate of 2,4-DCP decreased gradually. However, the biodegradation of phenol increased with the increase of run number of the batch experiments. In addition, continuous degradation of 2,4-DCP was also investigated. The results indicated that 2,4-DCP at the concentration ranged from 6.86 to 102.38 mg l −1 could be degraded at a dilution rate of 0.16 h −1 and the removal percentage ranged between 84 and 100%. The effect of interruption of 2,4-DCP supply to the bioreactor on the degradation ability of microbial cells was investigated by replacing 2,4-DCP with sodium acetate as the sole carbon source for 12 days. Intermission of 2,4-DCP supply did not cause the loss of chlorophenol-degrading ability.

Optimization of an Immobilized-Cell Biocatalyst for Production of 4-Cyanopentanoic Acid

Optimization of microbial cell immobilization, catalyst specific activity, and volumetric productivity were required for scale-up of the nitrilase-catalyzed hydrolysis of 2-methylglutaronitrile to 4-cyanopentanoic acid, an intermediate in the preparation of 1,5-dimethyl-2-piperidone. As an alternative to the immobilization of Acidovorax facilis 72W cells in carrageenan, immobilization in alginate, followed by cross-linking with glutaraldehyde and polyethylenimine, produced a catalyst which was stable in reaction mixtures containing high concentrations of 4-cyanopentanoic acid ammonium salt. Immobilization in alginate produced catalysts with a higher nitrilase specific activity than was achieved in carrageenan, and volumetric productivity of 4-cyanopentanoic acid was increased from 19 to 49 g/L/h. Substituting alginate for carrageenan also eliminated one process step in the immobilization. A further increase in volumetric productivity to 79 g/L/h was achieved by using an immobilized Escherichia coli transformant which expresses A. facilis 72W nitrilase.

An internal airlift loop bioreactor with Burkholderia pickttii immobilized onto ceramic honeycomb support for degradation of quinoline

A novel kind of bioreactor with a ceramic honeycomb support installed in a draught tube was developed and the ceramic honeycomb support could be used for immobilization of microbial cells. A strain of bacterium was isolated from activated sludge and identified as Burkholderia pickttii for degradation of quinoline and could grow on quinoline which served as a sole source of carbon, nitrogen and energy. Quinoline was degraded by the bioreactor in both batch and continuous flow operations when they were immobilized onto the ceramic honeycomb support. Experimental results indicated that quinoline could be degraded effectively by B. pickttii immobilized onto the ceramic support. Immobilized B. pickttii exhibited better stability in its metabolism and proliferation and degradation of quinoline in continuous flow operation conditions. More than 95% of quinoline could be removed for 4 h of hydraulic retention time (HRT). Quinoline was degraded through 2-hydroxy quinoline according to the analysis of gas chromatography–mass spectrum (GC–MS).

Mesoporous molecular sieve (MCM-41) as support material for microbial cell immobilization and transformation of 2,4,6-trinitrotoluene (TNT): a novel system for whole cell immobilization

The physical immobilization of whole microbial cells of Arthrobacter sp., Bacillus subtilis and Micrococcus luteus on the mesoporous molecular sieve of MCM-41 was studied. Cells of Arthrobacter sp. immobilized on the matrix of MCM-41 could be successfully employed in the treatment of 2,4,6-trinitrotoluene (TNT) and its subsequent transformation to amino products. Some significant advantages observed in this novel method of immobilization were the proliferation of whole cells while on the matrix of MCM-41, increase in tolerance (from 60 to 400 mg l −1) to TNT, repeated use of the immobilized cells for 20–23 cycles and total regeneration of support material.

Chitosan‐treated polypropylene matrix as immobilization support for lactic acid production using Lactobacillus plantarum NCIM 2084

AbstractAdsorption coupled with electrostatic interaction as an immobilization technique is an important microbial cell immobilization technique. Treatment of the polymer matrix with the cationic surface treating agent chitosan for lactic acid production has been studied. Cells of Lactobacillus plantarum NCIM 2084 were immobilized on a polypropylene (PP) matrix treated with different concentrations of chitosan. The biocatalyst adsorbed on the 1.0 g dm−3 chitosan‐treated PP matrix proved to be most effective. Repeated batch fermentation experiments showed that the immobilized biocatalyst could be recycled effectively 11 times. Studies were also carried out in a packed bed reactor with media recirculation. A high productivity of 7.66 g dm−3 h−1 could be obtained with a conversion of 94% and a yield of 97% at an average residence time of 30 h.© 2001 Society of Chemical Industry

A new method for immobilization of microbial cells by cross-linking

A method for immobilization of microbial cells was designed. The method uses generation of reactive aldehyde groups on the cell wall surface under conditions of periodate oxidation. The linking of aldehyde groups by various bifuctional aromatic diamines and then by glutaraldehyde produced immobilized cells, which are promising for use in biocatalysis with high-molecular-weight substrates.

The immobilization of microbial cells, subcellular organelles, and enzymes in calcium alginate gels. Reprinted from Biotechnology and Bioengineering, Vol. XIX, No. 3, Pages 387-397 (1977).

Saccharomyces cerevisiae cells, Kluyveromyces marxianus cells, inulase, glucose oxidase, chloroplasts, and mitochondria were immobilized in calcium alginate gels. Ethanol production from glucose solutions by an immobilized preparation of S. cerevisiae was demonstrated over a total of twenty-three days, and the half-life of such a preparation was shown to be about ten days. Immobilized K. marxianus, inulase, and glucose oxidase preparations were used to demonstrate the porosity and retraining properties of calcium alginate gels. Calcium alginate-immobilized chloroplasts were shown to perform the Hill reaction. Some experiments with immobilized mitochondria are reported.

Immobilization of cells by entrapping in aubasidan

A new technique of immobilization of microbial cells by entrapping in aubasidan, a microbial polysaccharide, was developed. This technique was applied to three cultures: Erwinia aroidea, Pseudomonas sp., and Alcaligenes faecalis, the producers of aspartase and L-aspartate beta-decarboxylase. The new method is effective. After immobilization, microbial cells retained 79-91% of their initial enzymatic activity.

A three-phase fluidized bed reactor in the combined anaerobic/aerobic treatment of wastewater

Aerobic degradation or polishing is an essential step in the combined anaerobic/aerobic treatment of wastewater. In this study, a type of porous glass beads was used for immobilization of microbial cells in a three-phase aerobic fluidized bed reactor (AFBR) with an external liquid circulation. The effects of superficial gas and liquid velocities on bed expansion, solid and gas hold-ups and specific oxygen mass transfer rate, kLa, were investigated. A tracer study showed that the mixing and flow pattern in the 8 dm3 reactor could be simulated by a non-ideal model of two continuous stirred tank reactors (CSTRs) in series. By treating an effluent from an upflow anaerobic sludge blanket (UASB) digester, the distribution of suspended and immobilized biomass in the reactor as well as the kinetics of COD removal were determined. The specific oxygen mass transfer rate, kLa, at a superficial gas velocity of 0.7 cm s−1 dropped by about 30% from 32 h−1 in tap water to 22 h−1 after a carrier load of 15% (v/v) was added. The measured kLa further dropped by about 20% to 18 h−1 in the wastewater, a typical value of the bubbling fermenters with no stirring. Compared with the aerobic heterotrophs under optimum growth conditions, the microbes in this reactor which was fed with anaerobic effluent plus biomass behaved like oligotrophs and showed slow specific COD removal rates. This might be attributed to the presence of a significant amount of obligate anaerobes and facultative organisms in the aerobic reactor. This was confirmed by a relatively low intrinsic oxygen uptake rate of the microbial population in the reactor, 94 mg O2 dm−3 h−1 or 19 mg O2g VS−1 h−1. © 1999 Society of Chemical Industry

The interphase technique: a simple method of cell immobilization in gel-beads

A variation of the emulsion techniques for microbial cell immobilization by encapsulation in gel beads is described. The utilized gels are silica gel or natural polymers like agar, agarose, phytagel or carrageenan. This technique utilizes the interfacial tension that is formed between two liquids of different polarity. The gel-beads are easily obtained and homogeneous in size.

Cadmium removal from dilute aqueous solution by beads of polysaccharide gels usable for microbial cell immobilization

Cadmium removal from dilute aqueous solution by beads of polysaccharide gels usable for microbial cell immobilization

Thermodynamics of sorption immobilization of microbial cells on solid surfaces

Thermodynamics of sorption immobilization of microbial cells on solid surfaces

Nitrate removal using a mixed-culture entrapped microbial cell immobilization process under high salt conditions

Brine wastes resulting from the regeneration of exhausted ion exchange resins require further treatment for final disposal. In this study, a mixed-culture entrapped microbial cell immobilization (EMCI) process for nitrate removal from brine wastes was examined. Because of the presence of elevated concentrations of sodium chloride or sodium bicarbonate in the brine waste, the effects of high salt concentrations on the mixed-culture EMCI process and sludge production were investigated. Denitrification capacity of the mixed-culture EMCI process was found to be slightly affected at sodium chloride or sodium bicarbonate concentrations up to 20 g/l. The process generally performs better than other biodenitrification processes in the presence of salt concentration typically required for the regeneration of ion exchange resins. The cell yields were estimated to be 0.11 gSS produced/g COD removal or 0.36 g SS produced/g nitrate-N removed. The mixed-culture EMCI process was found to be an economical alternative for treatment of brine wastes and exhibits a great potential to be coupled with an ion exchange process for complete nitrate removal. The proposed coupling represents a closed-loop treatment in which the brine waste from ion exchange processing is denitrified by the mixed-culture EMCI process and the denitrified effluent is recycled to regenerate exhausted resins, resulting in the reduction of salt requirements for regeneration.

Immobilized Cells in Meat Fermentation

The immobilization of microbial cells can contribute to fermented meat technology at two basic levels. First, the solid/semisolid nature (low available water) of the substrate restricts the mobility of cells and results in spatial organizations based on "natural immobilization" within the fermentation matrix. The microniches formed influence the fermentation biochemistry through mass transfer limitations and the subsequent development and activity of the microflora. This form of immobilization controls the nature of competition between subpopulations within the microflora and ultimately exerts an effect on the ecological competence (ability to survive and compete) of the various cultures present. Second, immobilized cell technology (ICT) can be used to enhance the ecological competence of starter cultures added to initiate the fermentation. Immobilization matrices such as alginate can provide microniches or microenvironments that protect the culture during freezing or lyophilization, during subsequent rehydration, and when in competition with indigenous microflora. The regulated release of cells from the microenvironments can also contribute to competitive ability. The regulation of both immobilization processes can result in enhanced fermentation activity.

Loofa (Luffa cylindrica) sponge as a carrier for microbial cell immobilization

Abstract The feasibility of using loofa (Luffa cylindrica) sponge as a carrier for cell immobilization was investigated. In comparison with other carriers used for immobilization by cell adhesion, the density of loofa sponge is very low while the porosity and specific pore volume are very high. Furthermore, loofa sponge is stable over the whole range of pH and can be autoclaved many times without any visible change in the shape, structure and texture. By simply inserting loofa sponge in a flocculating yeast cell suspension, the flocs were entrapped within the lattice structure and the immobilization was completed in less than 20 min. The immobilized cells grew within the void volume, reaching a high cell concentration of over 4.4 g-cells/g-sponge. As an example, the immobilized cells were used for ethanol production from both sucrose and molasses media. More than 35 repeated batches on sucrose medium were performed without any loss in the activity of the immobilized cells. Also with both sucrose and molasses media, more than 500 h of stable continuous processing were possible. During the continuous processing, the cells remained firmly immobilized to the sponge and the free cell concentration in the effluent was less than 0.1 g/l throughout the fermentation period. The above results demonstrate that loofa sponge is an excellent carrier for immobilization of flocculating cells.

Development of a gel and foam matrix as immobilization system for cells for microbial denitrification of water

Abstract An anaerobic denitrifying bacterium, Paracoccus denitrificans DSM 65, was used as the model organism for the immobilization of microbial cells in a gel and foam matrix (GFM) system. Polyurethane foam cubes were soaked with a suspension of P. denitrificans in a 3% alginic acid solution and then hardened in 0.1 M CaCl2 solution. The rate of nitrate reduction by P. denitrificans DSM 65 was determined by anaerobic incubation of the cells immobilized in GFM using water containing potassium nitrate as substrate and sodium acetate as carbon source. Screening for optimum immobilization conditions was performed in shake flask cultures at 38°C under anaerobic conditions. A pore density of 20 pores per inch (PPI) and a cube size of 1×1×1 cm was identified as optimum for nitrate and nitrite reduction. Crushing of the gel matrix by uniaxial compression was an effective means for enhancement of denitrification.

Poly-N-vinylcaprolactam gel: A novel matrix for entrapment of microorganisms

A new gel-type support poly-N-vinylcaprolactam for microbial cell immobilization is presented. The method allows one to obtain beads of biocatalyst in a single step. The properties of beads obtained using different types of gel stabilizers were compared; the best stabilizer was found to be tannin. The method developed was used for entrapment of viable bacterial cells and fungal spores. The biocatalysts obtained were used for transformations of both hydrophilic (sorbitol, indolyl-3-acetic acid) and lipophilic (cortexolone, hydrocortisone) substrates.