Chitosan beads immobilized manganese peroxidase catalytic potential for detoxification and decolorization of textile effluent
Introduction
Ever-growing chemical pollutants, especially dyes from textile sector are polluting the water reservoirs and in view of toxic nature of dyes, there is need to explore suitable remediation strategies [1]. Annually, 7 × 107 tons dyes are manufactured worldwide and a significant amount is lost during processing and dying, which ultimately mixed with water bodies. The dyes are extremely stable, and some typical dyes are highly resistant to primary treatment methods, including physical or chemical procedures, which are often expensive, and accumulation of concentrated sludge also causes secondary pollution issue [2], [3], [4]. Being less expensive, more efficient and environmentally-friendly, the biodegradation has been recognized as an effective tool for treatment of wastewater. Oxido-reductases enzymes (fungi, bacteria) have been performed outstandingly in treating wastes [5], [6], especially fungal peroxidases and laccases have shown a great potential for the remediation of dyes [7], [8], [9], [10], [11], [12], [13]. Nevertheless, the biological treatment utilizing native enzymes is often unsatisfactory in degrading and detoxifying pollutants because free enzymes encountered operational difficulties (pH, temperature variation and generation of toxic by-products) and complete mineralization of pollutant is not possible due to instability and deactivation of enzymes [13], [14]. Enzymes immobilization on suitable matrices is the ultimate solution, which enables enzymes recovery (an essential condition for enzyme re-uses). Besides, it provides stability to enzyme against variable conditions in reaction media since enzymes are sensitive to change in reaction conditions and resultantly, denatured under unfavorable conditions [6], [15], [16], [17]. Therefore, the immobilization offers various advantages over free enzymes under similar reaction conditions which enhanced catalytic efficiency as well as recycling of enzyme [12], [18].
Chitosan is an amine polysaccharide, product of deacetylation of chitin and is composed of randomly distributed-(1,4)-linked-glucosamine and N-acetyl-d-glucosamine units [19]. At present, chitosan and its derivatives are the focal points as an ideal support in enzyme immobilization [20], [21], [22], [23] since it is non-toxic and able to protect enzyme (i.e., toxic by-products, variation in reaction conditions and metal ions etc) for efficient activity in view of suitable mechanical stability, biocompatibility and biodegradability. It also enables the enzyme to be reutilized in several successive cycles [23], [24], [25], [26].
The MnP-mediated degradation is reported by various researchers using single pollutant as model. However, there is lack of comprehensive studies reporting real textile wastewater decolorization (containing mixture of dyes) by CI-MnP. Therefore, the principal objectives of the present study were to immobilize MnP enzyme on chitosan microspheres, characterize and application for the degradation of textile wastewater. The CI-MnP catalytic potential was evaluated by measuring decolorization, water quality and toxicity (cytotoxicity and mutagenicity). For toxicity measurement, standard bioassays were used and finally, several decolorization cycles were run in order to check the stability and reusability of CI-MnP.
Section snippets
Reagents and chemicals
Chitosan (CTS) (MW 20,000, degree of deacylation = 89.2%), glutaraldehyde (50%, v/v, aqueous solution), calcium chloride dihydrate (≥99%), acetic acid (≥99%), cyclophosphamide monohydrate (≥98%), methyl methanesulfonate (∼99%), potassium dichromate (≥99.0%), and sodium malonate dibasic monohydrate (98%) were purchased from Sigma-Aldrich Chemical Co. (St. Louis, MO, USA). Hydrogen peroxide (30% H2O2), boric acid (≥99.5%), mono-and dibasic sodium phosphate, and potassium hydroxide (KOH) were
Statistical analysis
All the experiments were carried out in triplicates, data points were averaged and reported as mean ± SD. Analysis of variance (ANOVA) was performed using statistical analysis system software (SPSS Statistics 21) and difference among treatments were considered significant at 95% confidence of mean (P < 0.05).
Immobilization of MnP on chitosan beads
MnP was immobilized on to chitosan beads that provided an excellent biocompatible surface since immobilization efficiency (EI) of 84.8 ± 2.34% for MnP was achieved. In order to develop mechanically stable and firm quality chitosan beads, varying concentrations of chitosan were tested for immobilization. As is seen from Fig. 1(A), elevated chitosan concentration has improved enzyme loading efficiency (ELE) progressively, whereas the best EI was obtained at 2.5% (w/v) chitosan. There are two
Conclusions
Chitosan beads immobilized MnP catalytic potential for detoxification and decolorization of textile effluent was evaluated and up to 90% degradation of pollutant in textile wastewater was achieved using CI-MnP within 5 h. Along with water quality improvement, the toxicity was also reduced significantly. Chitosan beads showed excellent enzyme immobilization efficiency and provides good stability since immobilized MnP exhibited considerable activity up to 10 consecutive decolorization cycles.
Acknowledgements
The authors are grateful to State Key Laboratory of Microbial Metabolism, and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China for providing experimental facilities. The technical and analytical help extended by Instrumental Analysis Center of SJTU is also thankfully acknowledged.
References (67)
- et al.
J. Haz. Mat.
(2015) - et al.
J. Environ. Chem. Eng.
(2015) - et al.
Chemosphere
(2005) - et al.
J. Hazar. Mat.
(2009) - et al.
J. Mol. Catal. B Enzym.
(2011) - et al.
J. Mol. Catal. B: Enzym.
(2014) - et al.
Int. Biodeter. Biodegr.
(2014) - et al.
Biochem. Eng. J.
(2016) - et al.
Int. J. Biol. Macromol.
(2015) - et al.
Bioresour. Technol.
(2015)
J. Mol. Catal. A Chem.
Adv. Environ. Res.
Carbohydr. Polym.
J. Environ. Manage.
Int. J. Biol. Macromol.
J. Mol. Catal. B: Enzym.
Int. J. Biol. Macromol.
J. Mol. Catal. B: Enzym.
Process Biochem.
J. Biol. Chem.
Bioresour. Technol.
Mutat. Res.
Carbohydr. Polym.
Process Biochem.
J. Mol. Catal. B: Enzym.
Food Chem.
J. Mol. Catal. B: Enzym.
Anal. Chim. Acta
J. Mol. Catal. B: Enzym.
J. Power Sour.
Appl. Surf. Sci.
Enzym. Microb. Technol.
Process Biochem.
Cited by (131)
Immobilization of laccase on magnetic PEGDA–CS inverse opal hydrogel for enhancement of bisphenol A degradation in aqueous solution
2025, Journal of Environmental Sciences (China)Manganese peroxidases as robust biocatalytic tool — An overview of sources, immobilization, and biotechnological applications
2023, International Journal of Biological MacromoleculesImmobilization of microbes and enzymes for textile wastewater treatment
2023, Current Developments in Bioengineering and Biotechnology: Advances in Eco-friendly and Sustainable Technologies for the Treatment of Textile WastewaterImmobilized enzyme systems for wastewater treatment
2023, Advances in Chemical Pollution, Environmental Management and Protection