Studies on Mechanisms for Lysine Production by Pyruvate Kinase-Deficient Mutants of Brevibacterium flavum

概要

論文の詳細を見る
Methionine-insensitive revertants with normal homoserine dehydrogenase (HD) derived from Brevibacterium flayum mutant No. 1-231, a lysine producer with S-(2-aminoethyl)-L-cysteine (AEC) resistance, methionine sensitivity, a low HDlevel and a pyruvate kinase (PK) defect, were still AEC-resistant and PK-deficient similar to No. 1-231. But they did not produce more lysine than the original strain, No. 15-8, from which strain No. 1-231 was derived. A high lysine producing mutant, No. 22, which was derived from strain No. 1-231, selected by sensitivity to β-fluoropyruvate (FP), and was defective in HD, produced more lysine than HD-defective mutants which were derived by two-step mutation from strain No. 1-231, selected by homoserine auxotrophy. Strain No. 22 did not showFP sensitivity under the conditions tested. Amongvarious lysine-biosynthetic enzymes examined, it had a higher level of aspartate-β-semialdehyde dehydrogenase than did its parent and the latter HD-defective mutants. Strain No. 22 produced 50 g/liter of lysine as the HC1 salt when cultured for 72 hr in a mediumcontaining soybean-meal hydrolysate, methionine and 100g/liter of glucose.
社団法人日本農芸化学会の論文