Int. Jr. Bioinformatic and Biological Sci. : v.2 n.3 and 4, p. 179-188. Dec. 2014

DOI No. 10.5958/2321-7111.2014.00015.8

Production parameter optimization for laccases by

Aspergillus niger

Priyam Vandana 1 , Harison Masih 1 , Yashab Kumar 1 , Ajay Kumar Singh 1 and

Jyotsna Kiran Peter* 1

Department of Microbiology and Fermentation Technology, Jacob School of

Biotechnology and Bioengineering, Sam Higginbottom Institute of Agriculture

Technology and Sciences, Allahabad, India.

*Corresponding author: jyots.kp@gmail.com

ABSTRACT

Laccase belongs to the family of blue multi-copper oxidases (MCOS) that has

three domain structures and usually contains four copper atoms. Aspergillus

niger species are reported to produce laccase. An attempt was made to screening,

optimization, production and partial purification of laccase enzyme produced

from Aspergillus niger. Guaiacol and acetate buffer were used to assay laccase

production. Laccase activity was highest when operated at the following conditions,

120 h incubation, 30°C temperature, pH-5, 2% glucose as carbon source and 2%

peptoneas nitrogen source in the production medium. The enzyme was partially

purified by ammonium sulfate precipitation and dialysis method.

Keywords: Laccase, Aspergillus niger, enzyme activity, optimization.

Laccases is a multicopper blue oxidase capable of oxidizing ortho- and para-

diphenols and aromatic amines by removing an electron and a proton from a

hydroxyl group to form radicals. First isolated in 1883 from Rhus venicifera, the

Japanese lacquer tree, laccases are commonly found in fungi (Thurston, 1994).

Extracellular laccases purified and characterized from various fungal sources

but majority of the studies have been focused on relatively few species such as

Trametes versicolor, Ganoderma lucidium, Neurospora crassa, Agracius bisporus,

Aspergillus nidulans, Pleurotous ostreatus, Panus trigrinus Trametes villosa (Ko

et al., 2001).

Laccases are of particular interest with regard to potential industrial applications

because of their capability to oxidize a wide range of industrially relevant

substrates. Their substrate versatility makes laccases highly interesting for various

applications, including textile dye bleaching, pulp bleaching and bioremediation

where enzymatic catalysis could serve as a more environmentally bening

alternative than the currently used chemical processes. Its potential application