Studies on the Citric Acid Fermentation (Part 1) Strain Screening and Medium Improvement

구연산 발효에 관한 연구 (제 1 보) 균주선정 및 배지 개량

Out of 11 organic acid producing strains isolated from fruits, soil, and air, one strain was selected for the study of the citric acid fermentation using Sakaguchi's medium. The organism was identified as Aspergillus niger. When Asp.niger was shaked at 3$0^{\circ}C$ in a cotton plugged 500 mι Erlenmeyer flask with 100 ml of Sakagnchi's medium containing 10% of glucose (Difco), 0.6% of peptone, and mineral, citric acid were produced at the level of 17 gram per liter in 14 days. The citric acid was also produced at the level of 35 gram per liter after the improvements of Sakaguchi's medium-the adaptation, peptone addition, aeration, methanol addition, and glucose addition.

자연계에서 유기산을 생성하는 균주 11 군주를 분리하여 그 중에 구연산 생성균 1종을 선정하여, 동정한 결과 Aspergillus niger로 나타났다. 분리된 균주로 500ml 삼각 flask에 Sakaguchi 배지 100ml를 넣고 3$0^{\circ}C$에서 발효한 결과 구연산이 17g/ι가 생성되었다. 또한 Sakagnchi 배지를 개량한 결과 즉 배지적응, peptone첨가, 통기 효과, methanol첨가 및 포도당 첨가 결과 구연산이 35g/ι가 생성되었다