Characterization and Partial Purification of Pectinase Produced by Aspergillus niger Using Banana Peel as Carbon Source

Abstract

Pectinases are group of enzymes which causes the degradation of pectin. Pectinases are of environmental and industrial importance due to their biotechnological and commercial potentials in waste water treatment, brewing industries, textile industries, food industries and paper industries among others. The present study was aimed at characterization and partial purification of pectinase produced by Aspergillus niger using banana peel as carbon source under submerged fermentation (SmF) system. Fungi were isolated from fruit wastes dump sites using standard microbiological technique. The isolates were characterized morphologically and microscopically before subjecting them to screening for pectinolytic ability using standard methods. Molecular identifications were carried out on the isolate with the best pectinolytic ability. Fermentation parameters optimized to increase pectinase activity include; incubation period, salt supplements, additional carbon source, inoculum sizes, pH, moisture contents and temperature using standard methods. The isolate with the best pectinolytic ability was identified as Aspergillus niger strain AH1 with GenBank accession number MK811422. The crude pectinase obtained were partially purified by ammonium sulphate precipitation, dialysis and gel filtration chromatography methods. Maximum pectinase activity of 575.37±0.67 U/mg/min/ml was obtained at day 3 of incubation, with addition of salt supplements, in the presence of sucrose as additional carbon source, 2 ml of 1 × 106 spores ml-1 of Aspergillus niger, pH 6, 100 ml moisture contents, and temperature of 50 0C. The specific activity increased with 1.38 fold while recovery yield was 8.94 %. The study confirmed that the isolated Aspergillus niger strain AH1 can produced maximum pectinase at optimized fermentation parameters and could be explored for pectinase production