Transfer of sucrose fermenting ability, nisin resistance and nisin production intoStreptococcus lactis712

A gene block controlling sucrose-fermenting ability, nisin resistance and nisin production was found to be transmissible by a conjugation-like process.The 'pSN' (sucrose nisin) plasmid was transferred from 8 different nisin-producing donor strains into MG1614, a plasmid-free derivative of Streptococcus lactis 712.In the new host low yields of a plasmid of approx.30 MDa were isolated but its authenticity as a pSN plasrnld has not yet been established.Possibilities for increased nisin yield by genetic manipulation in S. lactis 712 must exist.