Production of 6-hydroxynicotinic acid by nicotinic acid-assimilating Pseudomonas sp.

Pseudomonas sp.에 의한 nicotinic acid로부터 6-hydroxynicotinic acid의 생산

For the production of 6-hydroxynicotinic acid from nicotinic acid, bacteria capable of assimilating nicotinic acid as a sole carbon, nitrogen and energy source were isolated from soils. Among them, SH-007, newly isolated strain having the best acitivity of nicotinic acid hydroxylase was selected and identified as Pseudomonas sp. The specific acitivity of nicotinic acid hydroxylase of Pseudomonas sp. was highest when the strain was cultured at $30^{\circ}C$ for 24 hrs in the medium (pH 7.5) containing 2 g nicotinic acid, 1 g $(NH_4)_2SO_4$, and 0.5 g peptone per liter. The addition of 1.5 g/l of nicotinic acid into the 24 hrs incubated culture medium resulted in the 12% higher specific acitivity of nicotinic acid hydroxylase than that of the non-added control after further 18 hrs incubation. In the 6-hydroxynicotinic acid production through the reaction with resting cells, 2.22 g/l of 6-hydroxynicotinic acid was produced from 2 g/l of nicotinic acid after incubation of 3 hrs under optimum conditions, which correpsonds to 98.2% of theoretical 6-hydroxynicotinic acid yield.

미생물을 이용하여 nicotinic acid로부터 6-hydroxynicotinic acid를 생산하기 위하여 토양으로부터 nicotinic acid를 탄소원, 질소원 및 에너지원으로 이용하는 균주를 70종 분리 하였으며, 이들 균주로부터 nicotinic acid hydroxylase의 비활성이 가장 높은 균주인 SH-007를 선별하였고, Pseudomonas sp.로 동정되었다. Pseudomonas sp.의 SH-007의 nicotinic acid hydroxylase의 비활성은 배지 중 2 g/l nicotinic acid, 1 g/l($(NH_4){_2}SO_4$ 및 0.5 g/l peptone을 사용하여 초기 pH 7.5로 조정한 후 $30^{\circ}C$에서 24시간 배양할 때 가장 높았으며, Pseudomonas sp. SH-007를 24시간 배양한 후 1.5 g/l nicotinic acid를 첨가하고 18시간 배양을 계속하면 24시간 배양 때보다 nicotinic acid hydroxylase의 비활성이 12% 증가하였다. 한편, 휴지세포를 이용한 6-hydroxynicotinic acid 생산을 위하여 2 g/l nicotinic acid이 함유된 최적 반응조건하에서 3시간 반응시킨 결과 생성된 6-hydroxynicotinic acid는 2.22 g/l이었으며, 이때의 전환율은 98.2 %이었다.