Journal of Environmental Biology

Biodegradation of perylene and benzo [ghi] perylene (5-6 rings) using yeast consortium : Kinetic study, enzyme analysis and degradation pathway

S.K. Mandal and N. Das*

Bioremediation Laboratory,?? School of Bio Sciences and Technology (SBST), VIT? University, Vellore - 632 014, India

*Corresponding Author E-mail: nilanjana00@lycos.com

Key words

Benzo[ghi]perylene

Perylene

Microbial remediation

Yeast consortium

Publication Data

Paper received : 23.05.2016

Revised received : 29.11.2016

Re-revised received : 16.03.2017 Accepted : 08.08.2017

Abstract

Aim: The present work aims to demonstrate the ability of yeast consortium for degradation of perylene and benzo[ghi]perylene which may contribute towards the development of an appropriate in-situ bioremediation techniques.

Methodology: Degradation of perylene (five ring) and benzo[ghi]perylene (six ring) was evaluated using yeast consortia under optimized conditions. Rate of biodegradation was tested with various kinetic models and intermediate metabolites were identified by GC-MS and FTIR analysis. Involvement of enzymes viz., 1,2-dioxygenase, 2,3-dioxygenase, catalase, laccase, lignin peroxidase and manganese peroxide were noted during PAHs degradation.

Results: The yeast consortium YC02 (Hanseniaspora opuntiae NS02, Debaryomyces hansenii NS03 and Hanseniaspora valbyensis NS04) degraded 67 % perylene at initial concentration 50 mg l-1, whereas YC04 (Rhodotorula sp. NS01, Debaryomyces hansenii NS03 and Hanseniaspora valbyensis NS04) degraded 60 % benzo[ghi]perylene at initial concentration 40 mg l-1 after 6 days. The consortium YC02 and YC04 exhibited best reaction by first order kinetics with half life period of 3.397 days and 4.218 days for degradation of perylene and benzo[ghi]perylene, respectively. ??

Interpretation: Based on the metabolites identified by GC-MS and FTIR analysis, possible pathways of perylene and benzo[ghi]perylene degradation were proposed. The results of present study revealed that application of yeast consortium can be a valuable approach towards remediation of high molecular weight PAHs having more benzene rings.

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