Intraspecific Protoplast Fusion of Brevibacterium and Intergeneric Protoplast Fusion between Brevibacterium flavum and Corynebacterium glutamicum and the Metabolic Control of L-Lysine Biosynthesis in Improved Bacterial Strains

Brevibacterium flavum의 동종간 및 Corynebacterium glutamicum과의 이속간 원형질체 융합 및 개량균주의 L-Lysine 생합성의 대사제어

As a trial method of breeding L-lysine producing strains, the intraspecific protoplast fusion bet-ween Brevibacterium flavum ATCC 21528R and Brevibacterium flavum ATCC 21529S and the intergeneric protoplast fusion between Brevibacterium flavum ATCC 21528R and Corynebacterium glutamicum ATCC 13058S were performed. The optimum conditions for protoplast formation of these strains were examined and the effect of plasma expander on regeneration and/or fusion was also observed. Both fusants No. CH23 and No. CH4l showed higher productivity of L-lysine than those of parental cells under the optimum cultural conditions at a rate of 21％ and 8.9％, respectively. And, activity of several enzymes in L-lysine biosynthetic pathway including aspartokinase, a rate-limiting enzyme, was determined. Besides, metabolic control mechanism of L-lysine biosynthesis in fusant No. CH23 and in No. CH41 was investigated to compare with that of parental strains.

Lysine 생산균주를 개량하기 위한 시도로서 Brevibacterium flavum ATCC 21528R 과 Brevibacterium flvum ATCC 21529S의 동종간 및 Brevibacterium flavum ATCC 21528R 과 Corynebacterium glutamicum ATCC 13058S 와 의 이속간 원형질체 융합을 실시하였다. 이들 균주들에 대한 원형질체 형성의 최적조건을 조사하고 재생과 융합에서의 plasma expander의 효과를 검토하였다. 융합주 No. CH23과 No. CH41은 최적 배양조건 하에서 L-lysine 생산성이 모균에서보다 각각 21％와 8.9％ 향상된 것이었다. L-Lysine 생합성 회로상의 중심효소인 asparto-kinase를 포함한 주요효소의 활성을 측정하였고, 융합주 No. CH23과 No. CH41에서의 L-lysine 생합성 대사제어를 친주와 비교하였다.