Isomaltooligosaccharides Production Using α-Glucosidase Activity from Zalaria sp. Him3, a Fructooligosaccharides-Producing Yeast.

In this study, we aimed to develop isomaltooligosaccharides (IMO) production as a novel industrial application of Zalaria sp. Him3, fructooligosaccharides (FOS)-producing yeast. A utilization test of carbon sources by Zalaria sp. Him3 was performed using API 50CH. Subsequently, the strain was cultivated in maltose medium, and the culture supernatant was used as α-glucosidase (AGase). AGase activity was evaluated by determining the amount of p-nitrophenol (PNP) derived from PNP-α-1,4-glucoside. IMO production was measured at 30 °C in the reaction mixture containing 280 g/L maltose and 0.25 U/mL AGase. Zalaria sp. Him3 highly utilized glucose, mannose, maltose, sucrose, and trehalose. When the strain was incubated with 150 g/L maltose for 48 h, IMO (isomaltose, panose, and isomaltotriose) were confirmed in the culture supernatant and AGase activity was 0.0165 U/mL. During IMO production using AGase in the culture supernatant, approximately 98% of initial maltose (279 g/L) was degraded for 72 h. The maximum IMO concentration was 138 g/L after 12 h of reaction. Thus, the yield of IMO production by AGase was 49.5% of the initial maltose. Zalaria sp. Him3, which is the FOS-producing yeast, can also produce IMO and serves as an industrially promising enzyme resource for the production of multiple types of oligosaccharides.