Isolation, characterization of glycolipid type biosurfactant from endophytic Acinetobacter sp. ACMS25 and evaluation of its biocontrol efficiency against Xanthomonas oryzae

Acinetobacter sp. ACMS25, which showed inhibitory effect on Xanthomonas oryzae pv. oryzae XAV24 was tested for biosurfactant production. Preliminary characterization showed that this strain was positive for hemolytic and oil spreading activity and was able to reduce the surface tension of water from 71.9 to 37.6 mN/m. The biosurfactant produced by this strain was characterized as a 'glycolipid-type' based on thin layer chromatography (TLC), fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1HNMR) analysis. Inhibition studies showed that this biosurfactant was able to reduce the specific growth rate of X. oryzae by 38.4% and spermosphere population by 43.5%. Glycolipid biosurfactant treatment improved the germination and vigour index, when challenge inoculated with X. oryzae and this treatment was able to offer 76.9% disease protection efficiency against the rice blight disease in rice.