白曲霉产中温酸性α-淀粉酶固体发酵条件及粗酶酶学性质的研究

Study on solid-state fermentation condition and properties of a novel acid-stable alpha amylase from Aspergillus candidus strain Asp-amy1

对白曲霉菌株（Asp-amy1）的固态发酵条件进行研究,采用单因素实验和正交实验,获得该菌株产酶优化培养基为：麸皮42%、玉米粉7.5%、蛋白胨0.5%、发酵曲含水量50%、接种量30%（以干基计）、发酵时间60~72h、pH自然,平均酶活力达到1592U/g。通过对其酶学性质的研究发现,白曲霉菌株Asp-amy1所产生的酶为中温耐酸性α-淀粉酶,其最适作用温度为60℃,最适作用pH范围为4.5~7.0。在此最适作用pH范围内,常温酶液静置60min,残余酶活还有70%以上,这为解决淀粉酶和糖化酶联用提供重要的依据。

The solid-state-fermentation conditions for novel acid-stable α-amylase-producing strain Aspamy1 were studied.Through single factor and orthogonal test,the results showed the optimal conditions were wheat bran 42%,cornmeal 7.5%,peptone 0.5%,inoculation volume 30%（solid material）,initial containing water 50%,natural pH.According to above,we stop the fermentation time during 60~72 h.The activity of α-amylase reached 1592 U/g.The properties of novel acid-stable α-amylase showed that the optimal activity temperature was 60 ℃ and the optimal activity pH was at the range of 4.5~7.0.In this range of optimal pH,enzyme liquid laying 60 min at normal temperature.Its residual activity is more than 70%.It will provide an important basis for conjunction between amylase and glucoamylase.