Characterization and optimization of Bacillus subtilis ATCC 6051 as an expression host

► The genome of the Bacillus subtilis type culture collection strain ATCC 6051, which is the oldest available ancestor of the commonly used B. subtilis laboratory strain 168, was sequenced and analyzed. ► Pheno- and genotypic differences between the strains ATCC 6051 and 168 were elucidated. ► The strain ATCC 6051 shows promising characteristics of an alternative B. subtilis production host, such as no auxotrophies and higher maximal optical densities on complex media. ► To further evaluate the suitability of this strain as an alternative expression host an asporogenic mutant with reduced autolysis was constructed and investigated using an acetoin-controlled model expression system.