2.4. The stoichiometric model for Klebsiella pneumoniae
The simplified pathway models of aerobic and anaerobic glycerol metabolism in
Klebsiella pneumoniae were shown in Figs. 1 and 2. The pathways of biosynthesis are
simplified as follows [15]:
4C3H8O3 þ3NH3 þ30ATP ! 3C4H7O2N þ 4NADH2 þ6H2OC4H7O2N denotes the elemental composition of biomass corresponding to
molecular weight of 101 g mol1. In anaerobic model, the reaction from pyruvate
to acetyl-CoA was considered as two parallel reactions (v3 and v4) catalyzed
respectively by pyruvate formate-lyase (PFL) and pyruvate dehydrogenase complex
(PDH) [16,17]. In aerobic condition, only the pathway catalyzed by PDH is
considered since the enzyme activity of PDH ismuch higher than PFL [18]. Since the
energy consumed in the trans-membrane activities and any other maintenance are
unknown, a metabolic reaction that consumes excessive ATP (to ADP) is set up to
balance the formulated energy. All the reactions and compounds of the
stoichiometric matrix are listed in Appendix II.