Though both strains (A3CK and A7CK) were able to produce IAA
from all the isomers oftryptophan, they preferred Ltryptophan for
growth and IAA production (data not shown). The highest IAA
production in culture was recorded at 2mg/ml tryptophan level
for both the strains(Fig. 2B).Tryptophan is a known precursor of
IAA biosynthetic pathways (Spaepen etal.,2007). The indole-3-
pyruvate pathway was found in E. cloacae where thetryptophan
was also precursor in IAA biosynthesis (RyuandPatten,2008).