L-Tryptophan microbial prodn. - by cultivating Escherichia coli mutant under aerobic conditions, sepg. cell mass, suspending mass in buffer and reacting

摘要

The microbial prepn. of L-trytophan comprises (a) cultivating a L-tryptophan, tryptophanase negative mutant of Escherichia coil W 3110 in a nutrient salt soln. contg. assimilable C and N sources, inorganic salts and L-tryptophan, under aerobic conditions at 28-40 degrees C and at a constant pH in the region 6-8, and sepg. the cell mass formed from the suspension, when growth is complete; (b) suspending the damp cell mass obtd. in an inorganic buffer soln. of pH 7.5-8.5, adding indol, L-serine, pyridoxal phosphate and a non-ionic surfactant or a lipophilic adsorbent to the suspension, reacting this at 28-42 degrees C and finally isolating L-tryptophan from the reaction mixt. L-Tryptophan is an essential amino acid which is used as a nutrient and feedstuff additive and is also used for medical purposes. The reaction of indol and L-serine in the presence of the lipophilic adsorbents or non-ionic surfactants gives high yields and improved productivity, while avoiding the disadvantages of previous processes which used expensive C and energy sources and an excess of D, L-serine.