초록

III. 연구개발의 내용
(1) 다양한 자원으로부터 γ-PGA 생성 미생물 탐색
- 된장, 청국장, 고추장 등과, 다양한 토양, 퇴비, 볏짚, 갈대, 억새풀 등의 시료 수집 및 미생물 탐색
- 선발된 γ-PGA 생성 미생물 동정, 특성조사
(2) γ-PGA 생성 미생물 이용하여 고수율로 고분자 γ-PGA를 생산하는 공정
- γ-PGA 생성 미생물 최적 배양조건 탐색
- γ-PGA의 생산과 정제
- γ-PGA 최적 대량 생산 개발 공정 및 생산된 γ-PGA의 특성 조사

Abstract ▼

Poly-γ-glutamic acid (γ-PGA) is an anionic, naturally occurring, water-soluble homo polyamide consisting of D- and L-glutamic acid monomers connected by amide linkages between α-amino and γ-carboxyl groups. Over the 1500 colonies of bacteria isolated from soil samples. Among them, CS4, MJ80, HB31b3,

Poly-γ-glutamic acid (γ-PGA) is an anionic, naturally occurring, water-soluble homo polyamide consisting of D- and L-glutamic acid monomers connected by amide linkages between α-amino and γ-carboxyl groups. Over the 1500 colonies of bacteria isolated from soil samples. Among them, CS4, MJ80, HB31b3, HB31c1, H12c1 and J-11 that had the high yield of γ-PGA production were isolated and identified. The yield of γ-PGA was the highest level by 4.28% in Bacillus subtilis MJ80. To investigate the optimum production of γ-PGA, B.subtilis MJ80 was cultured in SB, SF, and GA medium under optimum culture condition. γ-PGA was produced 35-40g/L from Bacillus subtilis MJ80 in SB medium. γ-PGA was produced 55~60g/L in GA medium. And, γ-PGA was produced 16-20g/L in SF medium.
To investigate the purification and characterization of γ-PGA, B. subtilis MJ80 was cultured in SB, SF, and GA medium under the optimal culture condition. When the supernatant of culture broth was adjusted on pH 3.0, the purity and yield of γ-PGA was high.
When EtOH was added on 1:2.0 (v/v) ratio, yield of γ-PGA was over the 80%. γ-PGA was more clearly purified in 4-6 hours after treatment of proteinase K. To investigate the purity of γ-PGA, purified γ-PGA was treated by the trichloroacetic acid (TCA), this result γ-PGA produced from SB and SF medium was purified over 80%, and γ-PGA produced from Cheonggukjang was perfectly purified. And, to confirm the molecular weight of γ-PGA produced from Bacillus subtilis MJ80, when SDS-PAGE gel was treated on methylene blue as dye reagent, it had a high molecular weight (>200kDa). Purified γ-PGA from B. subtilis in SB, SF, and GA medium was proved on γ-PGA by FT-IR. Moisture adsorption of hydrogel from purified γ-PGA was 300 times. A simple and rapid method was tried and established to measure the content of γ-PGA in biological samples exploiting the complex formation between γ-PGA and cupric acetate. The adsorption capacity of γ-PGA to Cu2+ was calculated as 4.5 mole GA units to 1 mole Cu2+. Using this method, the content of γ-PGA in 4 samples (cultured from Bacillus subtilis MJ80 for each 1~ 4days) under fermentation process was determined as 2.87-6.2 mg per mL liquid samples. The content of γ-PGA in Cheonggukjang completely was determined as 14.8 g/kg dry weight, and more than half (8.4 g/kg DW) was distributed out of the bean surface. This property will give opportunities for easier control of contents and molecular weight of γ-PGA in fermentation processes in the factories.

목차 Contents

• 표지 ... 1
• 제출문 ... 2
• 요약문 ... 3
• SUMMARY(영문요약문) ... 6
• 목차 ... 8
• 제1장 서론 ... 9
• 제1절 연구개발의 필요성 ... 9
• 제2절 연구개발의 최종목표 ... 10
• 제2장 국내외 기술개발 현황 ... 11
• 제 1절 국내 연구 현황 ... 11
• 제 2절 국외 연구 현황 ... 11
• 제3장 연구개발수행 내용 및 결과 ... 13
• 제 1절 γ-PGA 생산 균주의 분리 및 동정 ... 13
• 제 2절 최적배양조건의 탐색 ... 24
• 제 3절 γ-PGA의 생산과 정제 ... 34
• 제 5절 γ-PGA의 특성조사 ... 41
• 제 6절 γ-PGA의 간이 정량법 ... 46
• 제4장 연구개발목표 달성도 ... 49
• 제1절 목표대비 달성도 ... 49
• 제2절 정량적 성과 ... 49
• 제5장 연구개발결과의 활용계획 ... 50
• 제6장 연구개발과정에서 수집한 해외과학기술정보 ... 51
• 제 1절 특허 정보 ... 51
• 제7장 기타 중요 변동사항 ... 54
• 제8장 국가과학기술종합정보시스템에 등록한 연구장비 현황 ... 55
• 제9장 참고문헌 ... 56