Journal of Pure and Applied MicrobiologyVol. 9 No. 2

Kinetics and Thermodynamics of Crude Laccase Mediated Decolorization of Acid Red 131 Obtained by Growing A.niger over Limonia acidissima Shell as Solid Support

S. Miruthula and S. Sridhar*

1Department of Biotechnology, Jeppiaar Engineering College, Chennai, India.

Received on 13 March 2015 and accepted on 18 April 2015

 

ABSTRACT

Synthetic Dyes from leather industries contain recalcitrant substances/complex pollutants which are difficult to degrade and may impact human health is a major health concern. Enzymes from microbes offer an attractive option for removal of synthetic dyes at low cost, better technology transfer and are eco-friendly. Solid-state fermentation uses inexpensive and widely available agricultural residues as substrates for enzyme production. Among various solid substrates, Limonia acidissima (Wood Apple) shell has been found to be a suitable substrate for producing enzyme by solid-state fermentation. The present study was undertaken to produce crude laccase on wood apple shell powder by using Aspergillus niger in solid-state fermentation. Decolorization of Acid Red 131 was studied using crude laccase. Various Physico-chemical parameters such as pH, temperature, Metal Ion and salts were studied. Maximum laccase production reached 108.4U/?g at 40% moisture. The decolorization studies reported that maximum decolorization was observed at dye concentration of 50mg/L after an incubation time of 60 minutes. The thermodynamic studies on decolorization follow first order kinetics and the reaction is exoergonic, ?G of the reaction is negative which supports the fast reactivity at the transition state.

Keywords : Laccase, Limonia acidissima, Physico-chemical parameters, Decolorization, Thermodynamic studies.