Aspergillus niger와 Penicillium notatum간의 lipase 우수 생성 종간 형질전환체를 획득하고, 유전분석과 정제를 통하여 다음과 같은 결과를 얻었다. P. notatum의 영양요구물을 확인하여 본 결과 Tyrosine 요구성임을 알 수 있었다. 핵전이를 위한 원형질체 형성 및 재생 조건에서는 Novozym 234의 농도 1%, 삼투안정제는 0.6M KCl, 효소의 처리시간은 180분 그리고 최적 pH는 5.8로 나타났다. 핵전이에 의한 형질전환의 빈도는 $1.3{ imes}10^{-4}{sim}3.8{ imes}10^{-4}$으로 비교적 낮은 편이었다. 유전적 안정성, conidia의 크기, DNA 함량의 측정 그리고 핵염색의 결과 형질전환체의 핵형은 aneuploid로 추정되었다. 형질전환체의 lipase 활성은 모균주와 비교하여 $1.2{sim}1.7$배 증가하였다.
Interspecific hybrids between Aspergillus niger and Penicillium notatum (Tyr-), hyperlipolytic enzyme-producing fungi, were obtained by nuclear transfer technique. Optimal conditions for formation of intergeneric hybrids were investigated. Maximum production of protoplasts was obtained by 1% Novozyme 234 at $30^{circ}C$ for 3 hrs and the most effective osmotic stabilizers for the isolation of protoplasts were 0.6 M KCl. Frequencies of hybrid formation by nuclear transfer were $3.8{ imes}10^{-3}{sim}1.3{ imes}10^{-3}$. From the observation of genetic stability, conidial size, DNA content, and nuclear stain, it was suggested that their karyotypes are aneuploid. The hybrids showed $1.2{sim}1.7$ fold higher lipase activities than parental strains. It was strongly supported by results of this study that nuclear transfer technique is much more efficient in the formation of intergeneric hybrids than protoplast fusion and is very useful for the improvement of strains.
