Evaluation of p-cresol degradation with polyphenol oxidase (PPO) immobilized in various matrices.
p-Cresol is an environmental pollutant due to its vast use, toxicity and persistence, nevertheless, its degradation in an enzyme is unclear. In this study, we used Pleurotus sp. isolate VLECK02 polyphenol oxidase (PPO) for the determination of p-cresol degradation. On the basis of UV, FT-IR and chromatographic (HPLC and GC-MS) analysis, 4-methylcatechol was identified as the main metabolite of p-cresol catabolism. In addition, batch and semi-continuous degradation of p-cresol (10 and 20 mM) were studied and compared by free and immobilized PPO in different matrices like sodium alginate (SA), sodium alginate-polyvinyl alcohol (SA-PVA) and sodium alginate-polyvinyl alcohol-silver nanoparticles (SA-PVA-AgNPs). The experimental data showed that an enzyme (PPO) immobilized in SA-PVA-AgNPs was completely degraded p-cresol at initial concentrations of 10 and 20 mM within 30 h. These results suggest that the enzyme immobilized in SA-PVA-AgNPs has achieved higher degradation rates at a given time than free PPO and PPO immobilized in SA-PVA and SA. The SA-PVA-AgNPs and SA-PVA immobilized enzyme could be reused for more than 12 and 8 cycles, respectively, without losing any degradation capacity. Moreover, the immobilized PPO showed higher tolerance to various temperatures and pH than free PPO. Hence, immobilized PPO could be useful for the bioremediation of environment contaminated with phenolic compounds like p-cresol.
Department of Biochemistry, Karnatak University, Dharwad, Karnataka, 580 003, India. vijuedalli@gmail.com.
Vijayalakshmi A
VA
Edalli
Department of Biochemistry, Karnatak University, Dharwad, Karnataka, 580 003, India.
Sikandar I
SI
Mulla
Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China.
Syed Ali Musstjab Akber Shah
SA
Eqani
Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China.
Gurumurthy D
GD
Mahadevan
National Center for Cell Science, University of Pune, Ganeshkhind, Pune, 411007, India.
Rohit
R
Sharma
National Center for Cell Science, University of Pune, Ganeshkhind, Pune, 411007, India.
Yogesh
Y
Shouche
Department of Biochemistry, Karnatak University, Dharwad, Karnataka, 580 003, India. cmkamanavalli@gmail.com.
Chandrappa M
CM
Kamanavalli
Biodegradation; Pleurotus sp. isolate VLECK02; Polyphenol oxidase (PPO); Silver nanoparticles (AgNPs); p-Cresol