Raw starch digesting of amylase from Pichia guilliermondii i-1899

Pichia guilliermondii i-1899の生産する菌体外アミラーゼの粗酵素および精製酵素によるコメ、コムギ、トウモロコシ、カンショ、バレイショの5種の生デンプンへの作用性を検討した。その結果、粗酵素液は地上デンプンをよく分解し、トウモロコシデンプンでは100%グルコースに分解した。また、その生デンプンへの吸着性はコムギデンプン以外の供試デンプンに約30%の割合で吸着された。一方、精製酵素の生デンプン分解活性ではA1、A2の2種のα-アミラーゼには作用性は認められず、グルコアミラーゼ(GA)のみで認められた。しかし、最終分解率はコムギで20%、コメで5%にすぎなかった。また、粗酵素および精製酵素(GA)の走査型電子顕微鏡による生デンプン粒分解過程の観察では分解初期段階でデンプン粒に垂直に穴を空け、そこから徐々に作用していく分解様式が認められた。走査型電子顕微鏡観察にあたりご尽力くださいました日本電子(株)営業部武満氏ならびに同社応用研究センター第2応用研究室柳原利成氏、川島徹也氏に感謝いたします。Raw starch digesting and adsorbing abilities on crude and purified extracellular amylase of Pichia guilliermondii i-1899 were investigated by using with raw starch of rice, wheat, corn, potato and sweet potato as a substrate. The crude enzyme effectively digested raw corn starch, and produced glucose as the end product that digesting ratio showed 100% recovery. The adsorbable ratio of crude enzyme on raw starch was between 31-35% on corn, rice, sweet potato, and potato starches. Purified α-amylase A1 and A2 had not the digestive abilities for five kinds of raw starch. But purified glucoamylase GA had the digestive ability for raw starch. Final digestive ratios of GA were in 20% on wheat and 5% on rice. The digestive reactions against to raw starch granules with crude or purified glucoamylase GA on the digesting stage were observed by scanning electron microscope. The both reactions on early stage were observed many pineholelike holes on surface of starch granules, and then gradually digested.11KJ00004311154departmental bulletin pape