From Left: Lokanand Koduru and Dr Meiyappan Lakshmanan
Lokanand Koduru 1, Yujin Kim 2, Jeongsu Bang 2, Meiyappan Lakshmanan 3, Nam Soo Han 2 & Dong-Yup Lee 1, 3
1 Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore
2 Brain Korea 21 Center for Bio-Resource Development, Division of Animal, Horticultural, and Food Sciences, Chungbuk National University, Republic of Korea
3 Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), Singapore
Published in Scientific Reports 2017 7(1): 15721 (Online Version)
Probiotics are live microorganisms which confer several beneficial properties to humans and have a current market of more than few billion dollars per year. However, the tremendous potential of probiotics is yet to be exploited owing to the complexity involved in the behaviour of different microbial strains under the influence of different diets and health conditions. Moreover, to what extent such beneficial effects are genus, species or strain-dependent remains to be characterized. In order to answer such questions, it is important to gain thorough insights of the physiology and metabolic capabilities of probiotic strains.
In this regard, Dr. Lee’s group in BTI is aiming to facilitate systematic understanding of the probiotic lactic acid bacteria (LAB) by taking advantage of their distinct fermentative groups and the corresponding unique metabolism. LAB is mainly classified into homofermentative, facultative heterofermentative and obligates heterofermentative groups, depending on the nature of metabolic pathways used and the resultant fermentative by-products. Recently, Lee and colleagues have spent efforts to reconstruct high-quality genome-scale metabolic model of the representative obligate heterofermentative LAB, Leuconostoc mesenteroides, to enable thorough understanding of various metabolic niches of this LAB group for the first time. This work, published in Scientific Reports, has contributed significantly to understanding of this group of LAB. In addition to establishing the predictive ability of the model, the study has led to novel hypotheses related to the energy metabolism of L. mesenteroides. Besides, Lee and colleagues concluded redox state as the dominant factor controlling the organism’s physiology, emphasizing its importance during consideration for probiotic applications.
Figure 1. Overview of L. mesenteroides metabolic network (iLME620) and comparison of its characteristics with other LAB.
A. Central metabolism of L. mesenteroides along with amino acid biosynthetic pathways present in iLME620. Reactions represented by ‘red’ lines are added to the network during the manual curation process. Reactions in ‘grey’ represent those absent in L. mesenteroides, but present in the other two LAB; reactions in ‘blue’ represent those present in L. mesenteroides and Lb. plantarum, but absent in Lc. lactis; reactions in ‘green’ represent those absent in L. mesenteroides and Lb. plantarum, but present in Lc. lactis; reaction with dotted line is absent in all three LAB B. Venn diagram showing comparison of EC numbers of iLME620 with the GEMs of Lactococcus lactis subsp. cremoris MG1363 and Lactobacillus plantarum WCFS1. C. Comparison of metabolic network characteristics of the LAB.