Figure 2.

Efficient production of optically pure l-alanine achieved by knocking out alanine racemase and glycerol by-product biosynthesis pathway

(A) Effects of individual and simultaneous knockout of two alanine racemase alr1 and alr2 on the optical purity of l-alanine produced by fed-batch fermentation of B. licheniformis.

(B) Characterization of the d-alanine dependence of B. licheniformis BLA3 by testing the growth performance in media containing various concentrations of d-alanine. Triplicate experiments were carried out for physiological measurements, and error bars represent standard deviations.

(C) Fed-batch fermentation of B. licheniformis BLA3.

(D) Fed-batch fermentation of B. licheniformis BLA4.