Abstract
Aim : This study aims to investigate the ability of laccase producing fungal strains Cladosporium uredinicola GRDBF21 and Bipolaris maydis GRDBF23 isolated from decaying wood bark in decolouration and detoxification of tannery effluent.
Methodology : Fungal strains from decaying wood bark samples were isolated by serial dilution technique followed by single spore isolation method. The selected fungal isolates were investigated for their laccase enzyme production. Their effect on physio-chemical properties of tannery effluent collected from final effluent drainage of a leather-tanning factory in Chrompet, Chennai, Tamil Nadu, India was analysed. Toxicity of treated and untreated tannery effluent was analysed by seed germination test.
Results : The lignolytic and constitutive producers of laccase enzyme, C. uredinicola GRDBF21 and B. maydis GRDBF23 exhibited a tolerance index of 1.2 and 1.5, respectively, at 60% effluent concentration. The isolates were able to increase pH and reduce colour, turbidity, total suspended solids and electrical conductivity of the effluent. Besides observing a decrease in the BOD and COD levels, there was also a reduction in the sodium and hexavalent chromium content. C. uredinicola GRDBF21 and B. maydis GRDBF23 treated effluent showed a seed germination percentage of 66.6% and 76.6%, respectively. The untreated effluent completely inhibited the seed germination.
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Interpretation : The study confirms that the fungal species C. uredinicola GRDBF21 and B. maydis GRDBF23 could be effectively used in decolouration and detoxification of tannery effluent.