Title Enzyme activity of Aspergillus section Nigri strains isolated from the Korean fermentation starter, nuruk
Author Eunji Jeong and Jeong-Ah Seo*
Address School of Systems Biomedical Science, Soongsil University, Seoul 06979, Republic of Korea
Bibliography Journal of Microbiology, 60(10),998-1006, 2022,
DOI 10.1007/s12275-022-2071-6
Key Words Aspergillus section Nigri, Aspergillus niger, phylogenetic analysis, β-glucosidase activity, protease activity, amylase activity
Abstract Aspergillus section Nigri is a fungus used industrially because of its ability to produce enzymes such as cellulolytic, amylolytic and proteolytic enzymes. In this study, we obtained twentyeight strains of Aspergillus section Nigri from the traditional Korean fermentation starter, nuruk, which is known as a mixed culture of enzymatic filamentous fungi and yeasts. All strains were identified as Aspergillus section Nigri through combined phylogenetic analysis using partial β-tubulin and calmodulin gene sequences. The cellulase, amylase and protease activities of Korean strains were measured and compared with ten reference strains of Aspergillus niger. Most Korean strains showed higher cellulolytic activity than reference strains, and Aspergillus neoniger KCN5 showed the highest β-glucosidase activity. Two-thirds of the Korean strains showed similar levels of α- and glucoamylase activity as the reference strains. The protease activity of Aspergillus section Nigri strains was the highest at pH 3.0, and A. niger KSJ2 showed the highest acidic protease activity. By comparing ten reference strains and twenty-eight Korean strains, our results suggested useful Aspergillus section Nigri strains from nuruk with high enzyme activity, such as KCN5 and KSJ2, and their potential for industrial applications as enzyme producers.