Microbial cultures usually produce a significant amount of acidic byproducts which can repress cell growth and product synthesis. Metabolic engineering provides a powerful approach to optimize the cellular activities and improve product yields by genetically manipulating specific metabolic pathways. In this study, an inducible PYK (iPYK) mutant of B. subtilis was constructed based on the outcome of metabolic modeling. The results demonstrate that good cell growth rate and low acetate formation can be attained at an appropriate PYK expression level. In Addition, the PYK mutation was explored...