Ecological and physiological characterization of ACC deaminase-producing bacteria isolated from specific sites in Yogyakarta, Indonesia

The decrease of plant growth and productivity may be due to environmental stresses that induce excessive ethylene synthesis. ACC (1-aminocyclopropane-1-carboxylate) deaminase-producing bacteria are known to decrease plant ethylene levels by converting the ethylene precursor, ACC to ammonia and a-ketobutyrate. This study was aimed to understanding ecological and physiological characters of ACC deaminase-producing bacteria. The bacterial strains used were Sphingobacterium multivorum BK1, Bacillus mycoides CB2, Pantoea dispersa CK4, Pantoea agglomerans KD6.2, Enterobacter ludwigii KW3, Bacillus aryabhattai TW7, Pseudomonas monteilii KS12, Pseudomonas putida KS16.2, Pseudomonas putida PIR 3C, Stenotrophomonas maltophilia PIR5, Lysinibacillus pakistanensis PIC5, Bacillus aryabhattai PIC11, and Roultella terrigena PCM8. It was observed that all bacterial strains demonstrated optimal growth at pH 6-8, temperature 25-30 degrees C, and oxygen requirement of aerobic to facultative anaerobic. All of strains have Phosphate Solubilizing Index between 1,1-3,04 and IAA (Indole-3-Acetic Acid) production level between 0,11-10,33 ppm.hour-1. In terms of antagonistic properties, all bacterial strains were found incapable of inhibiting Xanthomonas oryzae pv. oryzae and Ralstonia solanacearum growth. All bacterial strains were capable of using glucose, sucrose, cellulose and mannitol as the source of carbon and energy. In addition, all bacterial strains also demonstrated Cr6+ tolerance ofs 100-300 mg.L-1.