Figure 2
From: Accelerated green process of tetramethylpyrazine production from glucose and diammonium phosphate
The simplified acetoin metabolic pathway in B. subtilis CICC 10211 (up) and the spontaneous reactions [18] of acetoin and ammonium (down). Bold arrows with solid, dot, and dash-dot lines are reactions taking place in stage I, II, and III in Figure 1, respectively. EM, Embden-Meyerhof pathway; PDH, pyruvate dehydrogenase complex; LDH, lactate dehydrogenase; ALS, α-acetolactate synthase; ALDC, α-acetolactate decarboxylase; BDH, 2,3-butanediol dehydrogenase; AoDH, acetoin dehydrogenase enzyme system. Arrows with upper-case letter S are non-enzymatic spontaneous reactions.