Immobilization of polyphenol oxidase on chitosan–SiO2 gel for removal of aqueous phenol

Shao, Jianda; Ge, Huan; Yang, Yumin

doi:10.1007/s10529-007-9329-2

Cited by 34 publications

(18 citation statements)

References 10 publications

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“…It should be noted that the bare chitosan beads cannot be magnetized under this condition. The application of an external magnetic field may generate an internal magnetic field in the beads which will add to or subtract from the external field, i.e., the local magnetic field generated by the electronic magnetic moment will add vectorially to the external magnetic field (H ext ) to give an effective field (H eff ) [32,36].…”

Section: Resultsmentioning

confidence: 99%

“…In addition, the magnetic support could be easily separated from the reaction medium and stabilized in a fluidized bed reactor by applying a magnetic field. The use of magnetic beads could also reduce capital and operation costs [27][28][29][30][31][32]. Moreover, techniques employing magnetism are more amenable to automation and miniaturization [31].…”

Section: Introductionmentioning

confidence: 99%

“…The most well-known technique is the magnetically stabilized fluidized bed reactor (MFB). MFB reactor uses an externally applied, axially or transversely aligned magnetic field to independently control the magnetic particles movement in a column [32]. Magnetically stabilized fluidized bed exhibits combination of the best characteristics of both packed and fluidized bed reactor design [33].…”

Section: Introductionmentioning

confidence: 99%

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Preparation and characterization of epoxy-functionalized magnetic chitosan beads: laccase immobilized for degradation of reactive dyes

Bayramoğlu

Yılmaz

Arıca

2009

Bioprocess Biosyst Eng

112

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Cross-linked magnetic chitosan beads were prepared by phase-inversion technique in the presence of epichlorohydrin under alkaline condition, and used for covalent immobilization of laccase. The activity of the immobilized laccase on the magnetic chitosan was about 260 U (g/dry beads) with an enzyme loading of about 16.33 +/- 0.39 mg [(g/dry beads) mg/g]. Kinetic parameters, V (max) and K (m) values were determined as 21.7 U/mg protein and 9.4 microM for free enzyme, and 15.6 U/mg protein and 19.7 microM for the immobilized laccase, respectively. The operational and thermal stabilities of the immobilized laccase were improved compared to free counterpart. The immobilized laccase was operated in a batch reactor for the decolorization of reactive dyes from aqueous solution. The laccase immobilized on magnetic chitosan beads was very effective for removal of textile dyes from aqueous solution which creates an important environmental problem in the discharged textile dying solutions.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Preparation and characterization of epoxy-functionalized magnetic chitosan beads: laccase immobilized for degradation of reactive dyes

Bayramoğlu

Yılmaz

Arıca

2009

Bioprocess Biosyst Eng

112

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“…As chitosan is remarkably hydrophilic, biocompatible, and easy to be linked with enzymes and to be modified owing to the presence of abundant hydroxyl and amino groups, it has been widely used as immobilization carrier not only for xylanase [2,7], but also for other enzymes [11][12][13][14]. Meanwhile, some new treatments to chitosan carrier were continuously carried out to improve its immobilization efficiency and also to enhance its acidic and alkali stability.…”

Section: Introductionmentioning

confidence: 99%

Immobilization of Aspergillus niger Xylanase on Chitosan Using Dialdehyde Starch as a Coupling Agent

Chen

Liu

et al. 2009

Appl Biochem Biotechnol

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Dialdehyde starch (DAS) was used as a novel coupling agent to prepare chitosan carrier to immobilize the xylanase from Aspergillus niger A-25. Compared with glutaraldehyde-cross-linked chitosan (CS-GA) and pure chitosan beads, the DAS-cross-linked chitosan (CS-DAS) beads exhibited the highest xylanase activity recovery. The DAS adding amount and cross-linking time in CS-DAS preparation process were optimized with respect to activity recovery to the values of 1.0 g (6.7% w/v concentration) and 16 h, respectively. The optimum temperature of both the CS-DAS- and CS-GA-immobilized xylanase was observed to be 5 degrees C higher than that of free enzyme (50 degrees C). The CS-DAS-immobilized xylanase had the highest thermal and storage stability as compared to the CS-GA-immobilized and free xylanase. The apparent K (m) and V (max) values of the CS-DAS-immobilized xylanase were estimated to be 1.29 mg/ml and 300.7 mumol/min/mg protein, respectively. The CS-DAS-immobilized xylanase could produce from birchwood xylan high-quality xylo-oligosaccharides, mainly composed of xylotriose, as free xylanase did. The proposed CS-DAS carrier was more advantageous over the CS-GA or pure chitosan carrier for xylanase immobilization application.

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“…Other materials have been blended with chitosan to form composites for immobilizing reactive microbes or enzymes (Table 5). For example, fungal tyrosinase enzyme (TYR) has been immobilized using chitosan (Yamada et al 2005) and chitosan-SiO 2 gel (Shao et al 2007) to remediate phenol compounds in wastewater. TYR catalyzes the oxidation of phenol to o-quinones, which are then adsorbed by chitosan (Ikehata and Nicell 2008).…”

Section: Remediation Of Organic Contaminantsmentioning

confidence: 99%

Environmental Applications of Chitosan and Its Derivatives

Yong

Shrivastava

Srivastava

et al. 2014

Reviews of Environmental Contamination and Toxicology

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Chitosan originates from the seafood processing industry and is one of the most abundant of bio-waste materials. Chitosan is a by-product of the alkaline deacetylation process of chitin. Chemically, chitosan is a polysaccharide that is soluble in acidic solution and precipitates at higher pHs. It has great potential for certain environmental applications, such as remediation of organic and inorganic contaminants, including toxic metals and dyes in soil, sediment and water, and development of contaminant sensors. Traditionally, seafood waste has been the primary source of chitin. More recently, alternative sources have emerged such as fungal mycelium, mushroom and krill wastes, and these new sources of chitin and chitosan may overcome seasonal supply limitations that have existed. The production of chitosan from the above-mentioned waste streams not only reduces waste volume, but alleviates pressure on landfills to which the waste would otherwise go. Chitosan production involves four major steps, viz., deproteination, demineralization, bleaching and deacetylation. These four processes require excessive usage of strong alkali at different stages, and drives chitosan's production cost up, potentially making the application of high-grade chitosan for commercial remediation untenable. Alternate chitosan processing techniques, such as microbial or enzymatic processes, may become more cost-effective due to lower energy consumption and waste generation. Chitosan has proved to be versatile for so many environmental applications, because it possesses certain key functional groups, including - OH and -NH2 . However, the efficacy of chitosan is diminished at low pH because of its increased solubility and instability. These deficiencies can be overcome by modifying chitosan's structure via crosslinking. Such modification not only enhances the structural stability of chitosan under low pH conditions, but also improves its physicochemical characteristics, such as porosity, hydraulic conductivity, permeability, surface area and sorption capacity. Crosslinked chitosan is an excellent sorbent for trace metals especially because of the high flexibility of its structural stability. Sorption of trace metals by chitosan is selective and independent of the size and hardness of metal ions, or the physical form of chitosan (e.g., film, powder and solution). Both -OH and -NH2 groups in chitosan provide vital binding sites for complexing metal cations. At low pH, -NH3 + groups attract and coagulate negatively charged contaminants such as metal oxyanions, humic acids and dye molecules. Grafting certain functional molecules into the chitin structure improves sorption capacity and selectivity for remediating specific metal ions. For example, introducing sulfur and nitrogen donor ligands to chitosan alters the sorption preference for metals. Low molecular weight chitosan derivatives have been used to remediate metal contaminated soil and sediments. They have also been applied in permeable reactive barriers to remediate metals in soil and groun...

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Immobilization of polyphenol oxidase on chitosan–SiO2 gel for removal of aqueous phenol

Cited by 34 publications

References 10 publications

Preparation and characterization of epoxy-functionalized magnetic chitosan beads: laccase immobilized for degradation of reactive dyes

Preparation and characterization of epoxy-functionalized magnetic chitosan beads: laccase immobilized for degradation of reactive dyes

Immobilization of Aspergillus niger Xylanase on Chitosan Using Dialdehyde Starch as a Coupling Agent

Environmental Applications of Chitosan and Its Derivatives

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