Pseudomonas sp. LG2의 Ferulic acid esterase 및 Xylanase 유도와 부분적 특성

Abstract

리그닌 분해 세균인 Pseudomonas sp. LG2는 lignocellulose 기질을 분해하여 APPL 화합물을 생성하는 균주이다. 이 균주를 BSG(brewer's spent grain)가 함유된 배지에서 배양한 배양액에서 APPL 화합물을 확인하였다. 세포외 조효소들의 유도에 관한 여러 가지 탄소원의 영향을 조사한 결과 glucose 배지에서는 xylanase의 효소활성만 확인 되었고 xylose, arabinose에서 배양한 조효소에서는 FAE 및 xylanase의 효소활성이 없었다. Oat spelt xylan, HBSG I(hydrolyzed brewer's spent grain I), HBSG II(hydrolyzed brewer's spent grain II) 및 AFBSG(autoclaved fraction from brewer's spent grain)를 탄소원으로 배양한 조효소에서는 FAE 및 xylanase의 효소활성이 확인됐다. Pseudomonas sp. LG2를 oat spelt xylan, HBSG I, HBSG II 및 AFBSG를 탄소원으로 사용하여 14일 동안 배양하면서 배양기간에 따른 세포외 효소들의 FAE와 xylanase 활성을 조사하였다. Xylanase의 최고 활성은 xylan을 탄소원으로 6일간 배양 했을때 5.3 U/mg으로 가장 높았으며, FAE의 최고 활성은 AFBSG를 탄소원으로 배양했을 때 배양 8일째 15.4 mU/mg으로 가장 높았다. Oat spelt xylan, HBSG I, HBSG II 및 AFBSG를 탄소원으로 사용하여 배양한 배지에 분리된 ferulic acid가 확인되었다. 세포외 효소의 FAE 활성은 methyl ferulic acid, methyl caffeic acid, methyl p-coumaric acid에 대해 esterase의 활성을 보였으나, methyl sinapinic acid, methyl vanillic acid 및 methyl gallic acid에 대해서는 esterase의 활성이 없었다. Lignin degrading bacterium Pseudomonas sp. LG2 was able to degrade lignin substrate to a lot of APPL compound. APPL compound was detected in culture supernatants from Pseudomonas sp. LG2 grown with BSC(brewer's spent grain). FAE(ferulic acid esterase) and xylanase are induced from Pseudomonas sp. LG2 in the presence of carbon sources such as oat spelt xylan, HBSG I, II(hydrolyzed brewer's spent grain I, II) and AFBSG(autoclaved fraction from brewer's spent grain). However, xylanase and FAE are not induced by growth of Pseudomonas sp. LG2 on xylose and arabinose. Pseudomonas sp. LG2 is grown on medium containing oat spelt xylan, HBSG I, II and AFBSG and the induction of FAE and xylanase activities of extracellular proteins determined during 14 days. Maximum level of xylanase activity(5.3 U/mg) found at 6 days in culture contained oat spelt xylan as carbon source, whereas maximum level of FAE activity(15.4 mU/mg) was found at 8 days in culture contained AFBSG as carbon source. Most ferulic acid was released in culture supernatants when Pseudomonas sp. LG2 grown on oat spelt xylan, HBSG I, II and AFBSG. FAE of extracellular enzymes was also specific activity on methyl ferulic acid, methyl caffeic acid and methyl p-coumaric acid respectively, but not methyl sinapinic acid, methyl vanillic acid and methyl gallic acid.