Identification and Characterization of an Agarase- and Xylanse-producing Catenovulum jejuensis A28-5 from Coastal Seawater of Jeju Island, Korea

제주 연안해수로부터 한천 분해 효소 및 자일란 분해 효소를 생산하는 Catenovulum jejuensis A28-5의 동정 및 특성 규명

Strain A28-5, which can degrade xylan and agar in solid medium, was isolated from a coastal seawater sample collected from Jeju Island, South Korea. This strain was found to be a gram-negative, $Na^+$-requiring bacterial strain with a polar flagellum for motility. Additionally, the strain was tolerant to antibiotics such as ampicillin and thiostrepton. The G+C content of the genome was 43.96% and menaquinone-7 was found to be the predominant quinone. Major fatty acids constituting the cell wall of the strain were $C_{16:1}$ ${\omega}7c/iso-C_{15:0}$ 2-OH (23.32%), $C_{16:0}$ (21.83%), and $C_{18:1}$ ${\omega}7c$ (17.98%). The 16S rRNA gene sequence of the strain showed the highest similarity (98.94%) to that of Catenovulum agarivorans YM01, which was demonstrated by constructing a neighbor-joining phylogenetic tree. A28-5 was identified as a novel species of the genus Catenovulum via DNA-DNA hybridization with Catenovulum agarivorans YM01, and thus was named as Catenovulum jejuensis A28-5. The formation of tetramers and hexamers of xylooligosaccharides and (neo)agarooligosaccharides, respectively, were confirmed by thin-layer chromatography analysis using an enzyme reaction solution containing xylan or agarose with two crude enzymes prepared from the liquid culture of the strain.

Strain A28-5는대한민국 제주도 연안의 해수샘플로부터 고체배지내 xylan과 agar를 분해하는 균주로 분리되었다. Strain A28-5는그람 음성균으로 한 개의 polar flagella로 운동성을 갖는 $Na^+$ 이온 요구성 균주로 분석되었다. 또한 ampilcillin과 thiostreptone 등의 항생제에 내성을 보였다. Genome 내 G+C content는 43.96%이고, Menaquinone-7 (MK-7)을 predominant quinone으로 함유하고 있었다. Strain A28-5의 세포벽을 구성하는 주요 지방산은 $C_{16:1}$ ${\omega}7c/iso-C_{15:0}$ 2-OH (23.32%), $C_{16:0}$ (21.83%), $C_{18:1}$ ${\omega}7c$ (17.98%)였다. strain A28-5의 16S rRNA gene sequence는 Catenovulum agarivorans YM01와 가장 높은 상동성(98.94%)을 보였으며, Neighbor-Joining phylogenetic tree 제작을 통해서 Catenovulum agarivorans YM01와 가장 높은 근연관계를 보이는 것을 증명하였다. Catenovulum agarivorans YM01과의 DNA-DNA hybridization 분석을 통하여 A28-5을 Catenovulum 속의 신종으로 분류하여Catenovulum jejuensis A28-5로 명명하였다. 이 균주의 액체배양으로부터 준비된 두 종류의 조효소를 이용한 xylan 또는 agarose와의 효소반응액을 Thin layer chromatography로 분석하여 각각 tetramer와 hexamer의 xylooligosaccharides와 (neo)agarooligosacchardes가 생산되는 것을 확인하였다.