Whole Genome Shuffling of Bacillus subtilis for Enhanced Protease Production

Whole genome shuffling technique was used to enhance protease production by Bacillus subtilis B4.A candidate mutant library was constructed by UV irradiation of Bacillus subtilis B4.Based on the optimum conditions for protoplast preparation and regeneration,multi-parental whole genome shuffling was carried out with 4 mutant strains(BRS1,BRS2,BRS5 and BRS6) by PEG mediated protoplasts fusion.Then BRS1,BRS5 and BRS6 were identified by biparental inactivation method as 3 excellent strains with greatly improved protease activity and good genetic stability.The maximum activity was as high as 2175.81 U/mL,which was increased 3.01 fold compared with the initial strain B4.