DIFFERENTIATION OF 6 STRAINS OF BACILLUS-THURINGIENSIS BY HYDROLYZABLE FATTY-ACID COMPOSITION

Six potential biocontrol strains of Bacillus thuringiensis grown under identical conditions on fatty-acid-free King's B medium were differen tiated on the basis of their hydrolyzable fatty acid content. Thirty-f our compounds were identified as their methyl esters in hydrolysates, among which the major fatty acids were i-15:0 (13.7-23.2%), i-13:0 (6. 8-10.7%), i-14:0 (5.0-7.7%), 14:0 (3.0-4.1%), a-15:0 (3.9-9.9%), i-16: 0 (3.6-7.2%), 16:0 (3.2-11.6%), i-17:0 (3.2-9.8%), 18:0 (tr-13.5%), a monounsaturated C-16 acid (4.5-9.9%), a monounsaturated branched C-17 acid (2.8-5.8%), a diunsaturated C-18 acid (0-5.8%), and a monounsatur ated C-18 acid (0.3-4.8%). A cyclopropanoid fatty acid, cy17:0(9), was detected at low concentration in three strains, including the anthelm intic strain CR-371. The presence or absence and the relative ratios o f certain chromatographic peaks in combination with a Wilcoxon-signed- rank-test analysis of pairwise differences in the total chromatographi c profile distribution were used to differentiate the six bacterial st rains.