Mn2+ and Mg2+ synergistically enhanced lactic acid production by Lactobacillus rhamnosus FTDC 8313 via affecting different stages of the hexose monophosphate pathway
Article first published online: 6 DEC 2013
© 2013 The Society for Applied Microbiology
Journal of Applied Microbiology
Volume 116, Issue 3, pages 644–653, March 2014
How to Cite
Lew, L.-C., Choi, S.-B., Tan, P.-L. and Liong, M.-T. (2014), Mn2+ and Mg2+ synergistically enhanced lactic acid production by Lactobacillus rhamnosus FTDC 8313 via affecting different stages of the hexose monophosphate pathway. Journal of Applied Microbiology, 116: 644–653. doi: 10.1111/jam.12399
- Issue published online: 14 FEB 2014
- Article first published online: 6 DEC 2013
- Accepted manuscript online: 22 NOV 2013 07:14AM EST
- Manuscript Accepted: 15 NOV 2013
- Manuscript Revised: 10 OCT 2013
- Manuscript Received: 17 JUN 2013
- Malaysian Ministry of Science, Technology and Innovation (MOSTI). Grant Number: 305/PTEKIND/613222
- Malaysian Ministry of Higher Education (MOHE). Grant Number: 203/PTEKIND/6711239
- Universiti Sains Malaysia. Grant Number: 1001/PTEKIND/815085
- Lactobacillus ;
The study aimed to evaluate the effects of Mn2+ and Mg2+ on lactic acid production using response surface methodology and to further study their effects on interactions between the enzymes and substrates along the hexose monophosphate pathway using a molecular modelling approach.
Methods and Results
A rotatable central composite design matrix for lactic acid production was generated with two independent factors namely, manganese sulfate and magnesium sulfate. The second-order regression model indicated that the quadratic model was significant (P < 0·05), suggesting that the model accurately represented the data in the experimental region. Three-dimensional response surface showed that lactic acid production was high along the region where the ratio of MnSO4 to MgSO4 was almost 1 : 1, justifying the need for both Mg2+ and Mn2+ to be present simultaneously in stimulating the production of lactic acid. Molecular docking simulation was performed on a total of 13 essential enzymes involved in the hexose monophosphate pathway for the production of lactic acid with four different conditions namely in the presence of Mg2+, Mn2+, both Mg2+ and Mn2+ and in the absence of metal ions. Results showed that the presence of both Mg2+ and Mn2+ within the binding site improved the binding affinity for substrates in five enzymes namely, glucose-6-phosphate dehydrogenase, phosphogluconate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase, phosphopyruvate hydratase and pyruvate kinase.
Using response surface methodology and molecular modelling approach, we illustrated that Mg2+ and Mn2+ synergistically enhanced lactic acid production by Lactobacillus rhamnosus FTDC 8313 via affecting different stages of the hexose monophosphate pathway.
Significance and Impacts of the Study
Mg2+ and Mn2+ synergistically improved lactic acid production of Lact. rhamnosus via improved binding affinity of the enzyme–substrate along the hexose monophosphate pathway, instead of purely affecting growth as previously understood.