Isolation, identification, and optimization of laccase from Alternaria alternata

ABSTRACT

Laccase, lignin peroxidase, and manganese peroxidase have a synergistic effect on a wide range of recalcitrantcompounds. Among them, laccase is polyphenol oxidase widely available in fungi, plant species, and insects.Laccase has an important role in effluent decoloration, detoxification of pulp bleaching, and bioremediationprocess. Screening was carried out to find new fungal isolate for the presence of laccase activity with guaiacolas indicator compound. Sixteen fungal isolates were obtained from biodeteriorated agro waste and the woodsamples were collected from North Gujarat region of India. Among these isolates, one of the fungal isolateswas observed with good laccase activity and identified as Alternaria alternata. Laccase activity was determinedusing 2,2’-azinobis-(3-ethylbenzethiazoline-6-sulfonate) as substrate. Various production parameters such aspH, temperature, various carbon sources, nitrogen source, inducers, and cations were used to select the optimumcondition for further increase in the production of this enzyme. Maximum laccase activity was obtained withglucose and sucrose as carbon source, 0.2% ammonium sulfate as nitrogen source, and 0.06% Cu+2 with 1.5 mMveratryl alcohol as inducer under optimized condition.