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Purification and characterization of a lipopeptide produced by Bacillus thuringiensis CMB26
Author(s) -
Kim P.I.,
Bai H.,
Bai D.,
Chae H.,
Chung S.,
Kim Y.,
Park R.,
Chi Y.T.
Publication year - 2004
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/j.1365-2672.2004.02356.x
Subject(s) - lipopeptide , surfactin , bacillus thuringiensis , biology , biological pest control , microbiology and biotechnology , bacillales , bacillus subtilis , bacteria , chemistry , botany , genetics
Aims: To isolate an antagonist for use in the biological control of phytopathogenic fungi including Colletotrichum gloeosporioides , then to purify and characterize the biocontrol agent produced by the antagonist. Methods and Results: Bacteria that exhibited antifungal activity against the causative agent pepper anthracnose were isolated from soil, with Bacillus thuringiensis CMB26 showing the strongest activity. A lipopeptide produced by B. thuringiensis CMB26 was precipitated by adjusting the pH 2 with 3 n HCl and extracted using chloroform/methanol (2 : 1, v/v) and reversed‐phase HPLC. The molecular weight was estimated as 1447 Da by MALDI‐TOF mass spectrometry. Scanning electron and optical microscopies showed that the lipopeptide has activity against Escherichia coli O157:ac88, larvae of the cabbage white butterfly ( Pieris rapae crucivora ) and phytopathogenic fungi. The lipopeptide had cyclic structure and the amino acid composition was l ‐Glu, d ‐Orn, l ‐Tyr, d ‐ allo ‐Thr, d ‐Ala, d ‐Val, l ‐Pro, and l ‐Ile in a molar ratio of 3 : 1 : 2 : 1 : 1 : 2 : 1 : 1. The purified lipopeptide showed the same amino acid composition as fengycin, but differed slightly in fatty acid composition, in which the double bond was at carbons 13–14 ( m/z 303, 316) and there was no methyl group. Conclusion: A lipopeptide was purified and characterized from B. thuringiensis CMB26 and found to be similar to the lipopeptide fengycin. This lipopeptide can function as a biocontrol agent, and exhibits fungicidal, bactericidal, and insecticidal activity. Significance and Impact of the Study: Compared with surfactin and iturin, the lipopeptide from B. thuringiensis CMB26 showed stronger antifungal activity against phytopathogenic fungi. This lipopeptide is a candidate for the biocontrol of pathogens in agriculture.