Korean Chemical Engineering Research, Vol.49, No.1, 101-104, February, 2011
Phanerochaete chrysosporium 변이주에서의 Cellobiose Dehydrogenase(CDH)와 β-Glucosidase 활성 향상
Improvement of Cellobiose Dehydrogenase(CDH) and β-Glucosidase Activity by Phanerochaete chrysosporium Mutant
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초록
Hemoflavoenzyme으로서 cellobiose dehydrogenase(CDH)는 셀룰로오스를 분해하는 과정에서 세포 외부로 분비되는 효소로서 amorphous cellulose와 강하게 결합하여 셀룰라아제(cellulase)에 의해 microcrystalline cellulose의 가수분해를 증가시킨다. 따라서 CDH는 바이오 에탄올 생산의 당화공정에서 중요한 역할을 할 것으로 예상된다. 여러 백색부후균으로부터 CDH 생산이 높은 Phanerochaete chrysosporium ATCC 32629 균주를 선정하였으며, 균주로부터 생산된 CDH 효소활성의 최적 온도와 pH는 각각 55 ℃와 4이었다. CDH 활성을 증가시키기 위하여 P. chrysosporium ATCC 32629 균주를 돌연변이시켰다. 돌연변이는 새로운 시도로써 국부적으로 큰 에너지를 줄 수 있는 특징을 가진 양성자 빔을 이용하였다. 양성자 빔 조사 후 사멸율이 약 99.9%인 1.2 kGy에서 CDH 활성이 증가된 변이주를 얻었다. 선별된 변이주와 모균주를 액체배양했을 때 변이주가 모균주보다 CDH와 β-glucosidase 활성이 각각 약 1.4배와 20배 증가하였다. 따라서, CDH 뿐만 아니라 β-glucosidase 활성이 높은 P. chrysosporium 변이주를 확보하였다.
Cellobiose dehydrogenase(CDH) as a hemoflavoenzyme is secreted out of cell in the cellulose degradation. As CDH strongly bound to amorphous cellulose, it helps cellulose hydrolysis by cellulase. CDH may have an important role of saccharification process for bioethanol production. In this study, Phanerochaete chrysosporium ATCC 32629 was selected for the production of CDH among other strains tested. The optimal temperature and pH of CDH produced by P. chrysosporium ATCC 32629 were 55 ℃ and 4, respectively. To improve the activity of CDH, the mutation of P. chrysosporium was performed using proton beam that has high energy level partially. As a result, P. chrysosporium mutant with the high activity was selected at 1.2 kGy in a range of 99.9% lethal rate. The CDH and β-glucosidase activities of mutant were 1.4 fold and 20 fold higher than those of wild strain. Therefore, P. chrysosporium mutant with the high activities of CDH and β-glucosidase was obtained from mutation by proton beam irradiation.
Keywords:Cellobiose Dehydrogenase;β-Glucosidase;Phanerochaete chrysosporium;Proton Beam Irradiation;White-rot Fungi
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