Repeated-batch production of kojic acid in a cell-retention fermenter using Aspergillus oryzae M3B9

Abstract

A cell-retention fermenter was used for the pilot-scale production of kojic acid using an improved strain of Aspergillus oryzae in repeated-batch fermentations. Among the various carbon and nitrogen sources used, sucrose and yeast extract promoted pellet morphology of fungi and higher kojic acid production. Repeated-batch culture using a medium replacement ratio of 75% gave a productivity of 5.3 gL-1 day-1 after 11.5 days of cultivation. While batch culture in shake-flasks resulted in a productivity of 5.1gL-1 day-1, a productivity of 5gL-1 day -1 was obtained in a pilot-scale fermenter. By converting the batch culture into repeated batches, the non-productive downtime of cleaning, filling and sterilizing the fermenter between each batch were eliminated, thereby increasing the kojic acid productivity. © Society for Industrial Microbiology 2005.