Biochemical and pathogenic potential characterization of Serratia plymuthica UBCR_12 as promising biological agents for controlling Colletotrichum gloeosporioides

In effort to develop bacterial based biofungicide, a rhizobacterium Serratia plymuthica UBCR_12 showing antifungal activity against phytopathogen Colletotrichum gloeosporioides was successfully isolated. Prior to its mass application its safety aspect to the human being and environmental factors has to be characterized in detail as well as its efficacy. For this purpose, biochemical characterizations of the isolate involving chitinolytic activity assay based on colloidal chitin degradation, siderophore production assay using CAS medium, and hemolytic test to identify its pathogenicity potential was performed. Its antifungal activity based on its capability to inhibit mycelial growth of fungus finally was determined. The results showed that optimal chitinolytic activity (1.63 ± 0.15) of the isolate was at pH 7.0, temperature 30 ˚C. The isolate showed a typical response to substrate concentration 2% (w/v) of colloidal chitin. Furthermore, the isolate showed a positive reaction with CAS medium and could lyse red blood cell on the blood agar. This result will imply to mass production and future application of S. plymuthica UBCR_12 as a biocontrol agent for C. gloeosporioides. Hence precaution to the human health and environmental safety has to be taken into consideration for its application.