Abstract

The use of antimicrobial bioactive compounds is currently regarded as a novel technology for biological control against plant diseases. This study aimed to isolate bacteria for the production of valuable bioactive compounds with antimicrobial activity from the compost of green waste mixed with phosphate residues and straws. Pseudomonas aeruginosa CFSP1L1 was identified as the most efficient bacterium in nine isolated strains in terms of inhibitory effect against Salmonella spp., Streptococcus spp., and Escherichia coli (E. coli). This bacterium has also been shown to have antifungal activity against Fusarium oxysporum f. sp. albedinis (Foa) and Aspergilus niger (A. niger). Its antimicrobial activity was not abolished after the heat and enzymatic treatments, showing that P. aeruginosa CFSP1L1 acts by bioactive substances of a non-protein, non-lipid and non-saccharidic nature. In vivo, the treatment of no damaged apples and mandarins with a suspension of the antagonist P. aeruginosa CFSP1L1 (10⁸ CFU/ml) for 24 h and then inoculated with a suspension (107 CFU/ml) of A. niger and Foa, respectively showed that the bacterial strain CFSP1L1 completely inhibited the phytopathogenic effect of both fungi.

Keywords: Compost; Phytopathogens; Pseudomonas aeruginosa