Optimization of Laccase Production Parameters by Aspergillus niger from Different Eco-Logical Sites of Lahore
Optimization of Laccase Production Parameters by Aspergillus niger from Different Eco-Logical Sites of Lahore
Syeda Rubab Zaidi* and Safdar Ali Mirza
ABSTRACT
The present study comprises of isolation and screening of fungal isolates for laccase enzyme production from different environmental samples of soil, water and air obtained from selected areas of Lahore. A total 248 strains of microscopic fungi were cultured by using serial dilution method and plate assay method. Pure cultures of these strains were further inoculated on PDA (Potato Dextrose Agar) plates supplemented with indicator compounds guaiacol or tannic acid to check the laccase producing ability. Among 08 isolated strains belonging to Aspergillus species of microscopic fungi, only 04 strains were screened for laccase production. In order to select most potential laccase enzyme producing strain among different isolated strains, quantitative analysis was carried out. Results clearly indicated that Aspergillus niger isolated from soil sample collected from agricultural area produced remarkable zone diameter and culture colony diameter. The remaining strains showed variable results for enzyme production. Laccase enzyme production was carried out by screened strain of Aspergillus niger under submerged fermentation technique. Optimization of different cultural parameters that influence laccase enzyme biosynthesis by A.niger strain was done. To measure enzyme activity indicator compound guaiacol and acetate buffer were used. It has been found that laccase activity was maximum on day 9 of incubation when operated under following cultural conditions, 2 pH, 35ºC, 3.0 % wheat straw as carbon source among other synthetic (glucose and maltose), and agricultural sources (sugarcane bagasse, rice bran), 1.5% urea as nitrogen source among other sources that include peptone, yeast extract, ammonium sulpate and ammonium chloride. Abench top fermenter was used in order to carry out scaled up studies). All the optimized cultural conditions were adjusted to culture Aspergillus niger for enhanced production of laccase enzyme. Concentrated crude laccase enzyme extract was obtained by filtration and centrifugation. Partial purification was carried out by ammonium sulphate precipitation method and further purification was done by column chromatography and gel filteration method. It has been concluded that locally isolated strain A. niger was one of the potential and promising fungal isolate, screened for laccase enzyme activity, from soil sample collected from agricultural area near Harbans Pura, Lahore.
Novelty Statement | A novel strain of filamentous fungus Aspergillus niger i.e., SAN5 was isolated from soil sample collected from agricultural area Harbans Pura of District, Lahore Pakistan and screened for laccase enzyme production with promising potential.
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