Fed-Batch Fermentation of High-Content RNA Yeast by Using Molasses Medium.

당밀 배지를 이용한 고함량 RNA효모의 유가배양

  • 김재범 (동의대학교 미생물학과) ;
  • 권미정 (동의대학교 미생물학과) ;
  • 남희섭 ((주) 농심 상품개발연구소) ;
  • 김재훈 ((주) 농심 상품개발연구소) ;
  • 남수완 (동의대학교 미생물학과)
  • Published : 2001.12.01

Abstract

In order to maximize the RNA accumulation and biomass production is Saccharomyces cerevisiae MTY62, a high-content RNA yeast strain, batch and fed-batch cultures were performed. Among the feeding modes of fed-batch cultures examined, the intermittent feeding mode R\`(IFB-lV), in which 50 ml of 40% molasses and 20% com steep liquor (CSL) solution was intermittently fed for 5 times, resulted in the cell concentration of 33.8 g- dry cell weight/1 and the RNA concentration of 5221 mg-/l, and RNA content of 153 mg-RNA/g-dry cell weight. The constant fed-batch with feeding mode III (CFB-III), in which the feeding rate of 40% molasses and 20% CSL solution was stepwisely decreased from 48 mph (9-13 h), to 24 mph (13-21 h), and to 18 ml/h (21∼ 48 h), gave the highest cell concentration of 42.7 g-dry ceil weigh71 and R7IA concentration of 5536 mg-RNA/1, which were about 2.4-fold and 1.9-fold increased levels, respectively, compared to the results of batch culture. However, the RNA con- tent of 130 mg-RNA/g-dry cell weight of the fed-batch was lower than that of the batch culture (171 mg-RNA/g-dry cell weight) and other fed-batch cultures. When the specific growth rates in the fed-batch cultures were increased, the RNA contents increased. This result indicates that the RNA content is adversely proportional to the cell concen- tration. However, at the same specific growth rate, the RNA content was maintained at higher level in the intermit- tent fed-batch than in the constant fed-batch culture.

천연풍미소재로 정미성 nucleotide 함량이 높은 효모추출물을 만들기 위해서 세포내 RNA 함량이 높은 효모균주 S , cerevisat MTY 62를 선별하여TRh, 당밀과 CSL배지로 발효조 회분배양과 유가배양을 수행하였다. 여러가지 단양한 간헐적 유가배양 중에서 40% 당밀과 20% CSL의농축기질액을 50ml 다섯번 공급하는 간헐적 유가배양 (IFB-IV) 에서 최대 세포농도는 33.8g-DCW/1 RNA 농도는 5221 mg/l RNA 함량은 153 mg-RNA/g DCW 값을 나타내었다. 일정속도의 유가배양에서는 기질 요액(40% molasses, 20% CSL)을 배양 9~13시간에서는 49 ml/h 13~21 이시간에서는 24 ml/h 그 이후로는 18 ml/h 로 기질공급속도를 단계적으로 감소시키는 유가배양 (CFB-III) 에서 42.7g-DCW-1 최대 세포농도를 5545 mg RNA/1의 RNA농도를 보여, 간헐적 및 일정 속도 유가배양 중에서 가장 높은 세포농도와 RNA 농도 값을 나타내었다. 그러나 RNA 함량 면에서는 가장 낮은 130 mg-RNA/g-DCW 값을 보여다. 즉 세포농도가 높을수록 RNA 함량은 감소하는 경향을 나타내었다. 이 상의 두 가지 유가배양에 대해 비증식속도 ($\mu$)에 따른 RNA 함량을 조사한 결과, $\mu$값이 증가할수록 RNA 함량도 증가하였다. 그러나 일정한 $\mu$에서는 일정속도의 기질공급 방식보다 간헐적 기질공급 방식이 더 높은 RNA 함량을 나타내었다.

Keywords

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