碳源對Sordaria fimicola α-澱粉酶釋出之誘導

Abstract

Sordaria fimicola a-澱粉酶之釋出誘導，和碳源供應之相關性為研究主題。對a-澱粉酶的誘導而言，以澱粉及麥芽糖為碳源對酶誘導的效果最佳，乳糖及蔗糖也有部分誘導作用，但單糖類的葡萄糖、果糖或缺少碳源之培養基則無誘導作用。接種在澱粉培養基之茵絲，在生長期中只有少量的澱粉酶釋出，直到碳源耗盡、菌絲鮮重下降後才大量產生澱粉酶。顯示Sordaria fimicola必須生長在含澱粉培養基，且碳源全部耗盡後才會合成、釋出澱粉酶。3%澱粉培養基對澱粉酶之誘導效果最好，再增高培養基的澱粉含量並不能提高誘導作用。葡萄糖對澱粉酶之誘導有抑制作用。葡萄糖之濃度愈高，抑制效果也愈明顯。Sordaria fimicola受誘導而釋出的澱粉酶，並非單純一種a-澱粉酶。從初步的分析結果可以推論，被誘導而釋出的澱粉酶至少應有四種。

Correlation of excretory alpha-amylase induction of Sordaria fimicola with carbon nutrients was investigated. j10th of starch and maltose were the best carbon nutrients for the enzyme induction. While monosaccharides, such '; glucose and fmctose, or carbon source deficiency was ineffective. Low amylase activity was detected during the Jog-phase grO\vth of mycelia and a large amount of enzym<-: was excreted in the conseqnence or carboll starvatIon. Tlierefore, both of the inducer presentation and the carbon starvation were required for the amylase inducton of Son/aria fimicola. The medium containing 3% starch exhibited an optimal efIcct on the amylase induction and higher starch content then 3% did not show further enhancement. Addition of glucose to starch medium could decrease the level of amylase induction, and this effect was in proportion to the concentration of glucose. Excretory amylases induced from Sordaria jimicola showed highly heterogenous, and at least four kinds of amylases were mkrTcd from our preliminary analysis.