Streptococcus faecalis var. liquefaciens 전세포 고정화법을 이용한 Casein Phosphopeptides 생산

Production of casein phosphopeptides using Streptococcus faecalis var. liquefaciens cell immobilization

Streptococcus faecalis var. liquefaciens를 calcium alginate gel에 고정화 후 CPP생산 가능성을 실험하였다. 균체를 회수하여 담체에 고정화하는 방법보다는 배양액 전체를 고정화하는 방법이 보다 높은 생산성으로 CPP를 생산하였다. Streptococcus faecalis var. liquefaciens 전세포 고정화 방법에 의한 sodium casenate로부터의 CPP 생산의 최적조건은 bioreactor부피대비 bead사용량이 30%, 반응온도는 $50^{\circ}C$, 반응 pH는 7.0, 기질의 농도는 10% 이었다. 또한, 고정화 균체를 이용한 연속적인 생산은 회분식 반응에서 설정된 최적 조건하에서 20% 수준의 CPP를 최소한 1개월 이상 연속적으로 생산할 수 있었다.

Optimum conditions for production of casein phosphopeptides (CPP) from sodium casenate by immobilized cell culture of Streptococcus faecalis var. liquefaciens were investigated. Immobilized cells were made by mixing 60% sodium alginate solution with an equal volume of culture broth at the end of exponential phase and subsequently dropping the mixture into $CaCl_{2}$ solution. Optimum conditions for CPP production by the immobilized cells were the same as those ($50^{\circ}C$, pH 7.0, and 10% substrate concentration) by the crude enzyme solution from the supernatant of culture broth. Optimum loading volume of the immobilized cells into a batch reactor was 30% (w/v). Using a continuous reactor loaded by the immobilized cells under the identified optimal conditions, we were able to produce CPP continuously up to 30 days with a maximum CPP conversion efficiency of 20%.