A non-reducing saccharide-forming enzyme and a trehalose-releasing enzyme, which have an optimum temperature in a medium temperature range, i.e., a temperature of over 40 or 45.degree. C. but below 60.degree. C.; and an optimum pH in an acid pH range, i.e., a pH of less than 7. The two-types of enzymes can be obtained in a desired amount, for example, by culturing in a nutrient culture medium microorganisms capable of producing the enzymes or by recombinant DNA technology.