Introduction

Strain of Clostridium sensu stricto are early colonizers of the infant gut that can use the human milk oligosaccharides derived fermentation metabolite fucose and 1,2-propanediol (1,2PD). Fucose can be catabolized to 1,2PD which is metabolized by enzymes of the pdu operon to propionate and propanol. Clostridium perfringens exhibits a unique response to 1,2PD metabolism. We previously confirmed fucose and 1,2PD utilization in the bacterium. This study aimed to reveal fucose and 1,2PD mechanistic pathway in C. perfringens FMT 1006 from infant feces.

Method

The genome was sequenced and compare to reference strains. Growth kinetics were evaluated in yeast casitone medium (YC) supplied with glucose as positive control (YC-Glc, 50 mM), propanediol (YC-1,2PD, 43 mM), and glucose (10 mM) + 1,2PD (43 mM, YC-Glc-1,2PD). Fermentation metabolites and gases were analysis with GCMS and PTR-TOF-MS. RNA samples were collected for gene expression analysis using microarrays. Membrane staining and composition analysis by LCMS were performed.

Results

Genome analysis confirmed presence of the pdu operon including pduCDE, pduQ, pduP, pduL, and pduW. Gene synteny was highly conserved compared with other strains. The growth rate with YC-Glc was 0.24 OD/h, 1.45-fold higher than growth rate of YC-Glc-1,2PD (0.17 OD/h). C. perfringens grown in YC-Glc formed mainly lactate (42.5 mM from 24 mM glucose) while acetate was the main metabolite (9.7 mM from 5.3 mM glucose) during growth in YC-Glc-1,2PD. While C. perfringens produced propanol in YC-1,2PD, propionate production was compromised, which was supported by gene expression analysis and lack of expression of pduP, pduL and pduW. During growth in YC-1,2PD, membrane lipids polarity and membrane fluidity increased compared with YC-Glc.

Conclusion

C. perfringens metabolism of 1,2PD leads 1-propanol as the main and only product. These findings set the framework to understand HMO by-product metabolism by C. perfringens infant isolated species.