Novel Pathway for Corrinoid Compounds Production in Lactobacillus

Area of Science:

• Microbiology
• Biochemistry
• Metabolic Engineering

Background:

• Vitamin B12 (cobalamin) is an essential human metabolite with complex synthesis pathways.
• Understanding cobalamin biosynthesis in producer strains like Lactobacillus is crucial for optimizing production.

Purpose of the Study:

• To investigate the influence of key intermediate compounds on cobalamin synthesis in two Lactobacillus strains.
• To elucidate the specific roles of Co2+, 5,6-dimethylbenzimidazole, and L-threonine in corrinoid compound production.

Main Methods:

• Culturing of Lactobacillus reuteri CRL 1098 and Lactobacillus coryniformis CRL 1001 with varying media supplements.
• Analysis of corrinoid compound production.
• Purification and characterization of corrinoid compounds using LC-MS.
• In silico analysis and physiological studies.

Main Results:

• Addition of Co2+ and 5,6-dimethylbenzimidazole significantly increased corrinoid compound production in both L. reuteri CRL 1098 and L. coryniformis CRL 1001.
• L-threonine supplementation enhanced corrinoid production exclusively in L. coryniformis CRL 1001.
• LC-MS and in silico analyses indicated distinct final-step synthesis pathways for corrinoid compounds between the two strains.

Conclusions:

• Specific precursor additions differentially impact cobalamin biosynthesis in Lactobacillus strains.
• L. reuteri CRL 1098 and L. coryniformis CRL 1001 exhibit unique metabolic strategies for late-stage cobalamin synthesis.