Though both strains (A3CK and A7CK) were abletoproduce IAA
from all the isomers of tryptophan, they preferred L-tryptophan 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 the tryptophan
was also precursor in IAA biosynthesis(Ryu andPatten,2008).