Patent ID: 8481293

Claim:
A mutant microorganism isolated having the ability to produce putrescine wherein at least one gene selected from the group consisting of a speE gene encoding spermidine synthase, a speG gene encoding spermidine N-acetyltransferase, an argl gene encoding ornithine carbamoyltransferase chain I-monomer and a puuP gene encoding putrescine importer, which are involved in the putrescine degradation or utilization pathway, is inactivated or deleted and wherein a promoter of at least one gene selected from the group consisting of an argECBH gene encoding an operon for arginine biosynthesis, an argD gene encoding acetylornithine aminotransferase, and a speFpotE gene encoding inducible ornithine decarboxylase and putrescinelornithine antiporter is replaced with a strong promoter ; and wherein at least one gene selected from the group consisting of a puuA gene encoding y-glutamylputrescine synthase, a ygjG gene encoding putrescine transaminase and an argF gene encoding ornithine carbamoyltransferase chain F-monomer is further inactivated or deleted; and a speC gene encoding ornithine decarboxylase is further introduced or amplified.