혼효림으로부터 셀룰로오스분해 박테리아 분리 및 효소학적 특성규명 (Isolation and characterization of cellulolytic bacteria, Bacillus sp. EFL1, EFL2, and EFP3 from the mixed forest)

서지정보

· 발행기관 : 한국응용생명화학회
· 수록지 정보 : Journal of Applied Biological Chemistry / 61권 / 1호 / 59 ~ 67페이지
· 저자명 : 박화랑, 오기철, 김봉규

초록

본 연구는 경상남도 산청군 소재 경남과학기술대학교 학술림에서 채취한 토양으로부터 CMCase와 xylanase를 생산하는 3개의Bacillus종을 분리하였다. API kit 분석과 16S rRNA 유전자 염기서열 분석을 통해 3개의 균 모두 Bacillus종에 속하였으며, Bacillus sp. EFL1, EFL2, EFP3로 명명하였다. Bacillus sp.
EFL1, EFL2, EFP3의 최적 생장온도는 37 oC였으며, CMCase 와 xylanase의 활성은 배양 후 12시간에 최고에 달하였다.
Bacillus sp. EFL1의 CMCase 효소활성의 최적온도는 50 oC, pH는 5.0이었고, xylanase 효소활성의 최적온도는 50 oC, pH 6.0이었다. Bacillus sp. EFL2의 CMCase활성의 최적온도는60 oC, pH는 5.0이었고, xylanase 효소활성의 최적온도는 60 oC 였고, pH 3.0-9.0까지 비교적 높은 활성을 보였다. Bacillus sp.
EFP3의 CMCase의 최적온도는 50 oC, pH는 5.0이었고, xylanase의 최적온도는 50 oC, pH 4.0이었다. Bacillus sp.
EFL1, EFL2, EFP3의 CMCase는 모두 온도안정성이 낮았다.
또한 Bacillus sp. EFL1과 EFP3의 xylanase 역시 온도안정성이낮았지만, Bacillus sp. EFL2의 xylanase는 온도안정성이 높았다.

영어초록

This study was conducted to isolate the cellulolytic bacteria able to grow on LB- Carboxymethyl cellulose (CMC) agar trypan blue medium from the mixed forest and Larix leptolepis stands. Three bacterial strains with high activity against both CMC and xylan were isolated. Both API kit test and 16S rRNA gene sequence analysis revealed that the three different isolates belong to the gene Bacillus. Therefore, the isolates named as Bacillus sp. EFL1, Bacillus sp. EFL2, and Bacillus sp. EFP3.
The optimum growth temperature of Bacillus sp. EFL1, EFL2, and EFP3 were 37 oC. The optimum temperature for CMCase and xylanase from Bacillus sp. EFL1 were 50 oC. The optimum pH of Bacillus sp. EFL1 xylanase was pH 5.0 but the optimum pH of CMCase from Bacillus sp. EFL1 was pH 6.0. The optimum temperature of CMCase and xylanase from Bacillus sp. EFL2 was 60 oC, respectively. The optimum pH of CMCase of Bacillus sp.
EFL2 was 5.0, whereas xylanase showed high activity at pH 3.0- 9.0. The optimum temperature for CMCase and xylanase of Bacillus sp. EFP3 was 50 oC. The optimum pH for CMCase and xylanse was 5.0 and 4.0, respectively. CMCases from Bacillus sp.
EFL1, EFL2, and EFP3 were thermally unstable. Although xylanase from Bacillus sp. EFL1 and EFP3 showed to be thermally unstable, xylanase from Bacillus sp. EFL2 showed to be thermally stable. Therefore, Bacillus sp. EFL2 has great potential for animal feed, biofuels, and food industry applications.

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