Isolation and partial characterization of antifungal metabolites produced by bacillus sp. IBA 33

Abstract

Antifungal proteins produced by Bacillus sp.<br />IBA 33 were purified by ammonium sulfate precipitation<br />and DEAE-Sephacel column chromatography. The two<br />purified proteins inhibited the growth of Geotrichum can-<br />didum, the sour rot disease agent in lemon. The proteins<br />were stable at 20 (3 months), 40, 60 and 100C (30 min)<br />and remained active after sterilization at 121C for 15 min.<br />Their hydrophobic nature was proved and when were<br />developed with ninhydrin they did not show any free amino<br />groups. The infrared spectrum showed vibrational modes<br />corresponding to peptide, ester or ketone links and satu-<br />rated CH links corresponding to long chain fatty acids. UV<br />scan spectroscopy showed tyrosine and or tryptophan<br />amino acids in their composition. The remarkable thermo-<br />resistance of proteins may be a good feature to be used in<br />the development of a new biocontrol method of Geotri-<br />chum candidum