Studies on the Utilization of Cassava Starch by a Strain of Rhizopus and Aspergillus niger

Cassava 전분을 이용하는 Rhizopus 및 Aspergillus niger 에 관한 연구

Several species of the fungi were isolated from cassava(Manihot esculenta Gruntz) starch which had formed into pellet, those had been stored for a while in southern part of Thailand. The species of Rhizopus, Aspergillus niger, and Aspergillus fumigatus were identified. The experimental results are as follows; Dry weight increases were checked during the static liquid culture with modified Czapek Dox medium to which cassava starch was partly replaced to sugar, Aspergillus niger and Aspergillus fumigatus had grown more than Rizopus species when 6% cassava starch was replaced to sugar and had been cultured for 72 hours. Amounts of mycelial protein of Aspergillus niger were checked, the highest amount was shown in 6% cassava starch involved medium. When nitrogen sources were varied such as ammonium sulfate or urea against sodium nitrate, there was no significant difference in mycelial production. Alpha amylase activity of each fungus isolated here was checked, those of Aspergillus niger have shown the highest peak at 72 hours.

1. Cassava 전분(澱粉)을 이용(利用)하여 곰팡이를 $28^{\circ}C$에서 96시간(時間) 액체정치(液體定置) 배양(培養)한 바 배지중(培地中)의 Cassava 전분함량(澱粉含量)이 6%, 72시간(時間)일 때에 균체량(菌體量)이 가장 많았다. 2. Cassava 전분(澱粉)이 6% 함유(含有)된 배지(培地)에서 곰팡이를 배양(培養)하여 얻은 균체단백질량(菌體蛋白質量)은 Rhizopus는 48시간(時間) 배양(培養)하였을때 가장 많았고, Aspergillus niger 및 Aspergillus fumigatus에서는 72시간(時間) 배양(培養)했을 때 균체단백질량(菌體蛋白質量)이 많았다. 3. Cassava 전분량(澱粉量)을 4%, 6% 및 8%되게 변화(變化)시킨 배지(培地)에서 분리균(分離菌)을 접종(接種)하여 96시간(時間) 배양(培養)하면서 24시간(時間)마다 배양여액(培養濾液) 중(中)의 m-amylase의 활성(活性)을 측정(測定)한 바 8% 농도(濃度)에서 Aspergillus niger 및 Aspergillus fumigatus는 72시간(時間)일 때 높은 D.P 값을 얻었고. Rhizopus 는 144시간(時間)일 때 D.P 값이 높았다.