title: Glucose metabolic flux distribution of Lactobacillus amylophilus during lactic acid production using kitchen waste saccharified solution.
abstract: The (13) C isotope tracer method was used to investigate the glucose metabolic flux distribution and regulation in Lactobacillus amylophilus to improve lactic acid production using kitchen waste saccharified solution (KWSS). The results demonstrate that L. amylophilus is a homofermentative bacterium. In synthetic medium, 60.6% of the glucose entered the Embden-Meyerhof-Parnas (EMP) to produce lactic acid, whereas 36.4% of the glucose entered the pentose phosphate metabolic pathway (HMP). After solid-liquid separation of the KWSS, the addition of Fe(3+) during fermentation enhanced the NADPH production efficiency and increased the NADH content. The flux to the EMP was also effectively increased. Compared with the control (60.6% flux to EMP without Fe(3+) addition), the flux to the EMP with the addition of Fe(3+) (74.3%) increased by 23.8%. In the subsequent pyruvate metabolism, Fe(3+) also increased lactate dehydrogenase activity, and inhibited alcohol dehydrogenase, pyruvate dehydrogenase and pyruvate carboxylase, thereby increasing the lactic acid production to 9.03 g l(-1) , an increase of 8% compared with the control. All other organic acid by-products were lower than in the control. However, the addition of Zn(2+) showed an opposite effect, decreasing the lactic acid production. In conclusion it is feasible and effective means using GC-MS, isotope experiment and MATLAB software to integrate research the metabolic flux distribution of lactic acid bacteria, and the results provide the theoretical foundation for similar metabolic flux distribution.
authors.affiliation: School of Civil and Environmental Engineering, University of Science and Technology Beijing, 30 Xueyuan Road, Haidian District, Beijing, 100083, China; Key Laboratory of Educational Ministry for High Efficient Mining and Safety in Metal Mine, University of Science and Technology Beijing, Beijing, 100083, China.
authors.forename: Jianguo
authors.initials: J
authors.lastname: Liu
authors.forename: Qunhui
authors.initials: Q
authors.lastname: Wang
authors.forename: Hui
authors.initials: H
authors.lastname: Zou
authors.forename: Yingying
authors.initials: Y
authors.lastname: Liu
authors.forename: Juan
authors.initials: J
authors.lastname: Wang
authors.forename: Kemin
authors.initials: K
authors.lastname: Gan
authors.forename: Juan
authors.initials: J
authors.lastname: Xiang
mesh_terms: D001673:Biodegradation, Environmental; D003470:Culture Media / Q000378:metabolism; D005285:Fermentation; D005947:Glucose / Q000378:metabolism*; D019344:Lactic Acid / Q000378:metabolism*; D007778:Lactobacillus / Q000378:metabolism*; D009249:NADP / Q000378:metabolism; D012722:Sewage / Q000032:analysis / Q000382:microbiology*; D014866:Waste Products / Q000032:analysis*
chemical_list: D003470:Culture Media; D012722:Sewage; D014866:Waste Products; D019344:Lactic Acid; D009249:NADP; D005947:Glucose