Norihisa Kato
Hiroshima University, Japan
Title: Aspergillus derived protease as a novel bifidogenic factor
Biography
Biography: Norihisa Kato
Abstract
Traditionally, Aspergillus species have been widely used for the production of a variety of fermented Japanese foods including, miso, soy sauce, sake, and sake lees. However, there is limited study on the application of Aspergillus species for the production of functional foods beneficial for health. In a recent animal study, we observed a marked elevation in the colon Bifidobacterium and organic acids in rats fed Aspergillus-fermented burdock compared to burdock powder (Okazaki et al. Biosci Biotechnol Biochem 77: 53, 2013). Similar observations were made in rats fed with water-soluble fraction from the fermented burdock and other Aspergillus-fermented foods such as malted rice and multi-grain malt. Since the water-soluble fraction from the fermented burdock contained substantial amount of extracellular proteases derived from Aspergillus, we postulated that bifidogenic effects might be associated with Aspergillus-derived proteases. To test hypothesis, rats were fed a diet containing 0.1% protease A ‘Amano’ SD (Aspergillus oryza，Amano Enzyme Inc.) (Amano protease) and number of Bifidobacterium in colon was measured. The results showed a marked elevation in colon Bifidobacterium population (Yang et al. Biomed Rep 3: 715, 2015). Since the Amano protease preparation is a mixture of several proteases, we set out to identify the active protease responsible for the bifidogenic effect. Our results show an acid protease derived from Aspergillus oryzae to exhibit a potent bifidogenic effect that was lost when protease was inactivated. A dietary addition of 0.0384% acid protease was comparable to 5 to 10% of prebiotics (e.g., oligosaccharides and dietary fibers) in raising colon Bifidobacterium population. In conclusion, our findings provide an insight into novel applications of an acid protease derived from Aspergillus as a functional food supplement for colon health.
