Screening of Bacillus thuringiensis Strains Producing Zwit-termicin A and Its Synergetic Activity to Crystal Protein

摘要

Using E. coli as an indicative bacterium, a bioassay method of determining activity of Zwittermicin A was established (Fig. 1, 2). Eight kinds of liquid media were tested on the accumulation of Zwittermicin A. It was found that half strength L8 and Bp media proved to be favorable to Zwittermicin A. Both of them needed less time to release spores, being 38 and 36 hours respectively. 4 high-yield zwittermicin A strains, (serotypes were H_(3ab), H_(5ab), H_(22) and Bt 901) were identified from 48 Bacillus thuringiensis strains screened by our lab (Table 1).