A modified electroporation method using trehalose is presented for the transformation of Bacillus subtilis. The new method improved the transformation efficiency of B. subtilis nearly 2,000-fold compared with the usual method, giving 4 x 10(5) transformants/mu g DNA. Using this method, B. subtilis was engineered to improve production of antimicrobial lipopeptides and produced 1.8-fold more surfactin and 2.9-fold more fengycin.