Methods of Random Mutagenesis of Aspergillus Strain for Increasing Kojic Acid Production

Kojic acid is an organic acid that is commonly used in the pharmaceutical and cosmetic industries. This acid compound is a secondary metabolite produced by various microorganisms, one of which is Aspergillus oryzae. Typically, improving the strain can enhance kojic acid production. A mutation is one of the tools to perform strain improvement because the change in kojic acidproducing genes effectively increases kojic acid yield. A random mutagenesis is a classic approach for inducing and producing mutants with random mutations. The mutagenesis can be generated by the individual physical and chemical mutagen, combined physical and chemical mutagens, or initiate by protoplast preparation. Aspergillus strains that are exposed to physical mutagens (e.g., UV) or chemical mutagens (e.g., N-methyl-N-nitro-N-nitrosoguanidine (NTG)) showed their abilities in increasing kojic acid production. Several new mutation methods, such as Ion Beam Implantation and Atmospheric and room temperature plasma (ARTP), also showed good responses in enhancing the production of biological products such as kojic acid. This review compared different random mutagenesis methods of Aspergillus strain with various mutagen types to provide better insight for researchers in choosing the most suitable method to increase kojic acid production.