根霉和米曲霉的淀粉酶系对生木薯粉酒精发酵的影响

Effect of amylase system from Rhizopus and Aspergillus oryzae on ethanol fermentation with raw cassava starch

从20株霉菌中筛选到两株淀粉酶高产菌Rhizopussp.2和Aspergillus oryzae3811,它们的生淀粉分解酶活性分别为122.42、130.89U/g湿曲,熟淀粉酶活性分别为5180.06、5818.31U/g湿曲。Rhizopussp.2与Candida tropicalisXY-3共同发酵25%生木薯粉的酒精产率和发酵率分别为8.10%(v/v)和65.51%,与安琪酒精酵母共同发酵的酒精产率和发酵率分别9.20%(v/v)和74.40%;Asp.oryzae3811与C.tropicalisXY-3共同发酵的酒精产率和发酵率分别为5.80%(v/v)和46.91%,与安琪酒精酵母共同发酵的酒精产率和发酵率分别为7.30%(v/v)和59.04%。两个菌株的发酵性能差异主要是由二者的淀粉酶组成和比例不同造成的,Rhizopussp.2的淀粉酶系有5个组分,其主要活性组分分子量为99kDa;Asp.oryzae3811有8个组分,其主要活性组分分子量为50kDa。

Rhizopus sp.2 and Aspergillus oryzae 3811 Maximum raw-starch- digesting glucoamylase yield produced high level of raw-starch-digesting glucoamylase of Rhizopus sp.2 and Aspergiflus oryzae 3811 were 122.42 130.89U/g wet mouldy bran, respectively. Maximum amylase yield of them were 5180.06,5818.31U/g wet mouldy bran, respectively. Rhizopus sp. 2 and Aspergillus oryzae 3811 significantly hydrolysed 25 % （w/v） raw cassava starch slurry in synergism with Candida tropicalis XY-3 or Angle yeast to produce ethanol.When Rhizopus sp.2 was used,ethanol yield were 8.10% and 9.20%, respectively.While those were 5.80% and 7.30%, respectively when Aspergillus oryzae 3811 was used.The fermentation difference of Rhizopus sp.2 and Aspergillus oryzae 3811 were due to the difference of amylase of Rhizopus sp.2 and Aspergillus oryzae3811.The amylase of Rhizopus sp.2 had 5 proteins and the 99kDa protein had the highest activity.The amylase of Aspergillus oryzae 3811 had 8 proteins and the 50kDa protein had the highest activity.