미생물(微生物)에 의한 5'-GMP의 생산(生産)에 관한 연구(硏究) - 제2보(第2報). 5'-XMP aminase 생산균주인 Brevibacterium ammoniagenes BA 17-2의 생육도 -

Studies on the Fermentative Production of Guanosine-5'-Monophosphate by Microorganism - Part II. Growth responses of 5'-XMP aminase producing Brevibacterium ammoniagenes BA 12-7 -

전보(前報)에서 변이처리에 의해서 얻은 Brevibacterium ammoniagenes BA 17-2로부터 5'-XMP aminase를 생산(生産)하기 위하여 인산염, 마그네슘이온, 망간이온, thinamine의 예비적정농도를 정(定)하고자 생육도(生育度)를 조사했다. 본실험(本實驗)에서 배지중(培地中)의 인산염의 농도(濃度)가 균(菌)의 생육(生育)에 중요한 영향을 미치는 것을 보여주었다. $MgSO_4{\cdot}7H_2O$, 0.2% $MnSO_4{\cdot}H_2O$ 3mg/l, $thiamine{\cdot}HCl$를 포함한 배지(培地)를 사용하면 최대 균체량은 $KH_2PO_4$, $K_2HPO_4$ 각각 0.4%의 농도에서 얻어졌다. 이러한 인산염 농도 이상에서 균생육(菌生育)은 인산염 농도가 1%까지 증가함에 따라 저해되었지만 저해작용은 1%의 $MgSO_4{\cdot}7H_2O$와 3mg/l의 $thiamine{\cdot}HCl$을 첨가하여 해소되었다. 5'-XMP aminase 역가도 역시 인산염, 마그네슘이온, 망간이온, thiamine의 농도에 영향을 받았다. 그밖에 효소역가에 대한 배양 최적 pH와 온도는 각각 6.8과 $32^{\circ}C$로 밝혀졌다.

Growth responses of Brevibadterium ammoniagenes BA 17-2, which had been obtained by the treatment of several mutagens in our previous report, were investigated to select the preliminary optimal concentrations of phosphate, $Mg^{++}$, $Mn^{++}$ and thiamine for the production of 5'-XMP aminase. In this experiment it was shown that the concentration of phosphate in the medium has an important effect on the growth of microorganism. Using the medium containing 0.2% of $MgSO_4{\cdot}7H_2O$, 3mg/l of $MnSO_4{\cdot}H_2O$and $1\;mg/l$ of thiamine-HCl, the maximum cell mass was obtained at the concentration of 0.4% of $KH_2PO_4$ and $K_2HPO_4$, respectively. Above the concentration of these phosphates, cell growth was inhibited as the phosphate concentration increased to 1%, but the inhibition was overcome by the addition of 1% of $MgSO_4{\cdot}7H_2O$ and 3mg/l of thiamine-HCl. The 5'-XMP aminase activity was also influenced by the concentration of phosphate, $Mg^{++}$, $Mn^{++}$, and thiamine. In addition, the optimal culture pH and temperature for the enzyme activity were found to be 6.8 and $32^{\circ}C$, respectively.