Alcaligenes sp. GB-77에 의한 Polyhydroxyalkanoic Acid의 생산 = Polyhydroxyalkanoic Acid Production by Alcaligenes sp. GB-77

국문 초록 (Abstract)

Polyhydroxyalkanoic acid(PHA)를 생산하는 세균들을 하수처리장의 활성오니로부터 존화배양에 의하여 분리하였다. 이들 중 단일기질로부터 PHA를 생산하는 균주의 생리학적 성질을 검토한 결과 Alcaligenes 속으로 동정되었다. 균체 생육에 최적인 배양온도, pH는 각각 36℃, pH6.8로 나타났으며, 탄소원으로 과당 10g/l, 질소원으로 polypeptone 5g/l, Na_2HPO_4 1×10^-2 M, KH_2PO_4 1.3×10^2 M이었다. PHA 합성을 위한 최적조건을 조사하기 위하여 2단계 배양법을 이용한 결과, 배양온도 36℃, pH6.8, C/N 비 50이 PHA 합성에 최적인 것으로 나타났다. 탄소원을 간헐적으로 첨가하는 유가배양에 의하여 배양 60시간만에 건조균체량 17.4g/l, PHA 9.1g/l를 얻을 수 있었다. 추출, 정제된 PHA는 NMR에 의하여 분석한 결과 PHA/HV copolymer 임을 확인할 수 있었다.

다국어 초록 (Multilingual Abstract)

For polyhydroxyalkanoci acid (PHA) production, several microorganisms were isolated from sewage sludge. One of them, GB-77 strain, was chosen from its PHA/HV copolymer production on only fructose without cosubstrate. The isolated strain GB-77 was identified as the genus Alcaligenes. Optimal temperature and pH for cell growth were 36℃ and 6.8. Optimal medium composition was 10 g/l of fructose and 5 g/l of polypeptone, 1×10^-2 M Na_2HPO_4, 1.3×10^-2 M KH_2PO_4. To investigate the optimal condition for polyhydroxyalkanoic acid production two-stage culture technique was used; first stage for cell grown and second stage for PHA production on unbalanced growth conditions. Optimal conditions for high PHA production were C/N ratio 50, temperature 36℃ and pH 6.8. To overcome frutose inhibition on cell growth, intermittent feeding fed-batch culture technique was used. Total cell concentration was 17.4 g/l with 9.1 g/l of PHA. The purified PHA was identified PHA/HV copolymer by NMR analysis.