ISOLATION AND IDENTIFICATION OF ENDOPHYTIC BACTERIA OF BANANAS IN KENYA

Abstract

This study was conducted with the aim of isolating and identifying banana endophytic bacteria on the basis of their potential  as biological  fertilizer. Banana  materials were  collected from five different geographical regions to enhance diversity. Isolation of bacteria was done using five (5) different isolation media  and the isolates were characterized on the basis of their morphology, biochemical and molecular characteristics. A total of 214 bacterial isolates were obtained and characterized. Microorganism profiling was done using MALDI-TOF/MS and the isolates were clustered into 53 genotypes. Based on their functional characteristics, 43 isolates were selected for 16S rRNA gene sequencing. The 43 strains showed varied levels of positive nitrogenase activity as measured by the acetylene reduction assay and 37 strains were observed to solubilize phosphates by the formation of visible dissolution halos on agar plates (NBRIP medium). Siderophore  production of the isolates was determined using Chrome Azurol  S (CAS) agar plates and  all the isolates were observed to be positive for siderophore production with  3  strains showing distinctively high level of production. Using the 16S rRNA gene sequencing, the 43 strains were identified as Serratia spp. (17 strains), Pseudomonas spp. (12 strains), Enterobacter spp. (4 strains), Rahnella spp. (4 strains), Raoultella spp. (2  strains), Bacillus spp. (1 strain),  Klebsiella spp. (1 strain),  Yersinia spp. (1 strain) and Ewingella spp. (1 strain).  In  conclusion, banana endophytic bacteria were successfully isolated and identified, and  some of the isolates  showed  potential  of being  biological  fertilizers. However, greenhouse and field investigations are necessary to confirm this potentiality.