Abstract: The biological formation of 2AP, by several rhizobacterial isolates was studied on the medium supplemented with L-ornithine. Increase in concentration of 2AP, was observed when proline (4%), ornithine (4%) and putrescine (5%) were supplemented in growth medium. Acinetobacter bahayai-BM-28- KJ143625 was a highest 2AP producing isolate. Medium inoculated with different rhizobacterial isolates was observed with 2-15.4 fold increase over the control. A. bahayai-BM-28- KJ143625 was inoculated in the medium supplemented with different concentrations of 4-aminobutanal and 1-pyrroline. 2-AP was identified as the most important volatile found in the headspace of samples supplemented with different concentrations of 4-aminobutanal before sterilization. 1-pyrroline was found as one of the very important immediate precursor for 2AP synthesis by bacteria. Results of precursor analysis revealed that 2AP production occurs when 4-aminobutanal diethyl acetal deduced from ornithine/proline/putrescine is heat transformed to 1-pyrroline which ultimately is converted into 2AP by bacterial system.