Study on organic matter decomposition and siderophore production of rhizobacteria isolated from black pepper grown in Loc Ninh, Binh Phuoc province, Vietnam

This study was carried out determining capability of organic compound decomposition and siderophore synthesis of 39 plant growth promotion rhizobacteria strains isolated from rhizosphere of black pepper (Piper nigrum L.) in a previous study. The ability to degrade organic compounds including proteins, lipids, cellulose and chitin was investigated by agar well diffusion method. The ability to produce siderophore was qualified by liquid CAS method and strains with good results were further investigated by PS-CAS agar plate method. The results showed that the number of bacterial strains capable of degrading protein, cellulose, chitin and lipid were 37, 27, 16 and 6, respectively. Twenty-two strains changed color of CAS agar, of which 6 strains had a band width of 4.5 cm. The seven best strains identified were Proteus mirabilis (LD2), Bacillus megaterium (LT4), B. subtilis (LT2), B. cereus (LD7, LD8, LD16, LT19) by Matrix Assisted Laser Desorption/Ionization-Time of Flight method. These were plant growth-promoting rhizobacteria that had been reported on potential applications in agriculture.