Abstract:
The constraint of plant cultivation in the tropics is low nitrogen (N) content in soil. The
application of nitrogen fixing bacteria (NFB) is not only fulfill the N demand but also provide
the phytohormones Indole acetic acid (IAA) and exopolysaccharides (EPS). The objective of the
experiment was to was to isolate the NFB from the rhizosphere of nutmeg tree and characterized
their IAA and EPS production in a liquid culture. The NFB was isolated by serial dilution plate
method on Tryptic Soy Agar. In order to test the ability of various NFB isolates to produce IAA
and EPS, all isolates were grown in Tryptic Soy Broth for 72 hours at room temperature. The
results showed that at the end of experiment the media acidity was shift from neutral to alkaline.
The population of five isolates of NFB was approximately 8-9 log10 (of CFU/mL). The IAA
production in liquid culture of all isolates was similar but the EPS production was varied and
depend on the isolates, The highest EPS content was in PL1 culture and the lowest was in the
culture of PL5. This experiment verified that the NFB isolated from nutmeg rhizosphere enable
to produce IAA and EPS.
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