Summary
Through the course of five rounds of mutagenesis of a genetically-engineered strain ofAspergillus awamori, the yield of a heterologous protein (the acid protease, calf chymosin) increased four-fold. This was accomplished through the use of an agar plate screen incorporating the colony restrictor 2,6-dichloro-4-nitroaniline (dichloran) and the acid protease inhibitor diazoacetyl-norleucine methyl ester (DAN) to reduce high background concentrations of the native acid protease. A miniaturized liquid culture growth method using 24-well culture plates was an intermediate screen between agar plate and shake flask cultures. Analysis of broth samples for active calf chymosin was accomplished with a highly specific, 96-well microtiter plate turbidimetric assay.
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Lamsa, M., Bloebaum, P. Mutation and screening to increase chymosin yield in a genetically-engineered strain ofAspergillus awamori . Journal of Industrial Microbiology 5, 229–237 (1990). https://doi.org/10.1007/BF01569680
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DOI: https://doi.org/10.1007/BF01569680