Simple method for the isolation of the antilepidopteran toxin from Bacillus thuringiensis subsp. kurstaki

A protein with a molecular mass of 66 kDa was isolated by a simple, rapid, and inexpensive method, using 3-N-morpholinopropanesulfonic acid, potassium thiocyanate, and dithiothreitol, from a mixture of spores, parasporal crystals, and cell debris of Bacillus thuringiensis subsp. kurstaki. The protein was active against the third instar larvae of Trichoplusia ni, was soluble in 19 mM Na2CO3, and was characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and confirmed as the insecticidal component of the 132-kDa protoxin of B. thuringiensis subsp. kurstaki by an enzyme-linked immunosorbent assay using antibodies prepared against the protoxin.