Screening of production of industrial cellulase by Aspergillus niger sp. isolated from salt ecosystem

Abstract

Aspergillus is the most important cellulase enzyme producer. Isolation of native species of Aspergillus in order to investigate the potential of cellulase production is the aim of this research. 50 air and soil samples were taken from Howz-e Soltan Lake, Aran- Bidgol Salt Lakes and were cultured on a specific culture medium (such as Rose Bengal plate) and the colonies were identified by macroscopic, microscopic, biochemical, and molecular PCR methods. Cellulase enzyme activity was done quantitatively and qualitatively. Plackett-Burman method was used to optimize screen for significant factors in enzyme production. The phylogeny tree of the best cellulase enzyme producing strains was drawn with Mega7 software. Among the 10 Aspergillus niger species isolated, No. 7 had the highest amount of cellulase production. Screening results showed that a mixture of wheat straw and rice bran (in the ratio of 70:30), humidity of 37.5%, a range of CaCo3, inoculation of 106 spores per gram, and the presence of carboxymethyl cellulose
90%, and incubation at a temperature of 25 ◦C resulted in the maximum production of cellulase enzyme. Aspergillus niger is a halophilic fungus that has a high capacity to produce enzymes in industry.