Abstract
The effect of penicillin G (k) was first investigated on L-homoserine production by Micrococcus glutamicus 534-Co 147 (a threonine requiring mutant). The addition of 4μ/ml of penicillin, 7 to 9 hours after inoculation, brought about the conversion of L-homoserine to L-glutamic acid production. Similar phenomena were observed in L-lysine and L-valine fermentations. In these cases, a homoserine requiring and a leucine requiring mutant of M. glutamicus were used respectively. A marked conversion from lysine and valine to glutamate accumulation occured by penicillin addition. However, in L-isoleucine fermentation with Brevibacterium ammoniagenes ATCC 6871, no glutamate accumulation took place and isoleucine yields were remarkably decreased.
