Screening of lysine-producing strains of brevibacterium with a rotating liquid culture system using a large number of micro-holes for individual cell cultivation

Summary With the technique of rotating liquid culture system in 7000 bottomless micro-holes, mutant strains having urease activity higher than that of the original strain were screened out in a medium with urea as a sole nitrogen source. A strain having a lysine yield of 12.5% and urease activity 20% higher than those of the original strain was isolated. The technique is suitable for screening strains where visual methods are available to estimate the amount of metabolite.