Crop production is challenged in our world by
increasing food demands, decrease natural resource
bases and climatic change. Nowadays plant growth
regulators works like fertilizers in increasing plant
growth production efficiency and needed to produce
in large industrial scale. Fermentation condition and
medium constituents can significantly affect on the
product production and designing an acceptable
fermentation medium is critical importance. In this
paper Fusarium sp. could be considered as
promising indole-3-acetic acid producers with the
ability to improve the production using statistical
methods. The results showed that fermentation type,
incubation temperature and L-tryptophan were the
most influencing parameters on the production.
Maximum IAA production by Fusarium oxysporum
was 300.4 mg/l obtained under the fermentation
conditions: temperature at 25oC, incubation period 5
days, pH 7, inoculums size 2%, shaking rate at 150
rpm and medium constituents: Glucose 40 g/l, yeast
extract 3 g/l, L-tryptophan 1 g/l, KH2PO4 2 g/l,
NaNO3 4 g/l, MgSO4·7H2O 0.1 g/l with regression
analysis (R2) 99.67% and 2.12-fold increase in
comparison to the production of the original level
(142 mg/l).