세포외 단백질분해효소를 생산하는 신종세균 Chryseobacterium sp. JK1은 토양으로부터 분리되었다. JK1 균주는 $30-35^{circ}C$에서 skim milk를 첨가한 고체배지상에서 가장 큰 투명환을 보여주었다. 액체배지에서 JK1 균주의 세포생육은 24시간에 최대이었고, 세포외 단백질분해효소의 최대활성은 정지기인 22시간에 560 unit/ml에 도달하였다. Nutrient 배지에 maltose 혹은 glucose, mannitol을 첨가하면 생육이 향상되었지만, 단백질 분해효소 생산은 64-77%로 저조하였다. Skim milk 혹은 beef extract, yeast extract, malt extract, tryptone의 첨가는 향상된 생육과 줄어든 효소생산을 보인 반면, $(NH_4)_2HPO_4$ 또는 $(NH_4)_2SO_4$의 첨가는 저조한 생육과 121-146%의 향상된 효소생산을 보여 주었다.
A novel Chryseobacterium sp. JK1 strain producing extracellular protease had been isolated from soil. The largest clear zones were observed on nutrient agar plates supplemented with 1% skim milk at $30-35^{circ}C$ along with the growth of Chryseobacterium sp. JK1. The cell growth of JK1 strain was maximal at 24 h and maximum protease activity was reached up to 560 unit/ml at the stationary phase in liquid culture. In the presence of maltose, glucose or mannitol in Nutrient broth, cells grew well, but protease were produced poorly with lower production yields of 64-77% than in NB broth only. Similarly, the addition of skim milk, beef extract, yeast extract, malt extract or tryptone showed good growth and poor enzyme production. On the contrary, the addition of $(NH_4)_2HPO_4$ or $(NH_4)_2SO_4$ gave poor growth and good enzyme production of 121-146%.
