Microbial production of lysine and threonine from whey permeate.

Extracellular accumulation of lysine and threonine was investigated in modified whey permeate by using Brevibacterium lactofermentum ATCC 21086 and Escherichia coli ATCC 21151. Whey permeate was prepared from whey by membrane ultrafiltration, and lactose was hydrolyzed by treating permeate with HCl or beta-galactosidase. The highest amount of lysine (3.3 g/liter) was produced from a mixture of acid-hydrolyzed whey permeate and yeast extract (0.2%). The highest amount of threonine (3.6 g/liter) was produced from a mixture of whey permeate, (NH(4))(2)SO(4) (1.4%), yeast extract (0.1%), and Na(2)CO(3) (0.3%).