Cobalamin production by Lactobacillus coryniformis: biochemical identification of the synthetized corrinoid and genomic analysis of the biosynthetic cluster.

Andrea Carolina Torres,Julieta Bonacina,Lucila Saavedra,María Pía Taranto,Graciela Font,Verónica Vannini

doi:10.1186/s12866-016-0854-9

Andrea Carolina Torres, Julieta Bonacina + Show 4 more

Open Access

https://doi.org/10.1186/s12866-016-0854-9

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Abstract

BackgroundDespite the fact that most vitamins are present in a variety of foods, malnutrition, unbalanced diets or insufficient intake of foods are still the cause of vitamin deficiencies in humans in some countries. Vitamin B12 (Cobalamin) is a complex compound that is only naturally produced by bacteria and archea. It has been reported that certain strains belonging to lactic acid bacteria group are capable of synthesized water-soluble vitamins such as those included in the B-group, as vitamin B12. In this context, the goal of the present paper was to evaluate and characterize the production of vitamin B12 in Lactobacillus coryniformis CRL 1001, a heterofermentative strain isolated from silage.ResultsCell extract of L. coryniformis CRL 1001, isolated from silage, is able to correct the coenzyme B12 requirement of Salmonella enterica serovar Typhimurium AR 2680 in minimal medium. The chemical characterization of the corrinoid-like molecule isolated from CRL 1001 cell extract using HPLC and mass spectrometry is reported. The majority of the corrinoid produced by this strain has adenine like Coα-ligand instead 5,6-dimethylbenzimidazole. Genomic studies revealed the presence of the complete machinery of the anaerobic biosynthesis pathway of coenzyme B12. The detected genes encode all proteins for the corrin ring biosynthesis and for the binding of upper (β) and lower (α) ligands in one continuous stretch of the chromosome.ConclusionsThe results here described show for the first time that L. coryniformis subsp. coryniformis CRL 1001 is able to produce pseudocobalamin containing adenine instead of 5,6-dimethlbenzimidazole in the Coα-ligand. Genomic analysis allowed the identification and characterization of the complete de novo biosynthetic pathway of the corrinoid produced by the CRL 1001 strain.

Highlights

Despite the fact that most vitamins are present in a variety of foods, malnutrition, unbalanced diets or insufficient intake of foods are still the cause of vitamin deficiencies in humans in some countries
Cobalamin production by L. coryniformis CRL 1001 In order to evidence the production of cobalamin by L. coryniformis CRL 1001, we use S
The results of the bioassay showed that the cobalamin requirements of the indicator strain were corrected when Cell Extracts (CE) of L. coryniformis CRL 1001 were added; the halo diameter obtained was similar to that obtained with a solution of standard cyanocobalamin (CN-Cbl)

Summary

Introduction

Despite the fact that most vitamins are present in a variety of foods, malnutrition, unbalanced diets or insufficient intake of foods are still the cause of vitamin deficiencies in humans in some countries. It has been reported that certain strains belonging to lactic acid bacteria group are capable of synthesized water-soluble vitamins such as those included in the B-group, as vitamin B12 In this context, the goal of the present paper was to evaluate and characterize the production of vitamin B12 in Lactobacillus coryniformis CRL 1001, a heterofermentative strain isolated from silage. It has been described that in some anaerobic bacteria, the adenine and other ligands can replace DMB giving as a result pseudocobalamin (pseudo-B12) and other active cofactors [3] This soluble compound is one of the most complex non-polymeric macromolecules produced in the cell and only a reduced group of bacteria and archaea are able to synthesize it. The results of this research provide the first evidence of vitamin B12 synthesis by a L. coryniformis strain

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