Biosynthetic pathway and improve production of Vitamin B12 by Lactobacillus coryniformis CRL 1001

TORRES ANDREA CAROLINA; VANNINI VERÓNICA; FONT GRACIELA; SAAVEDRA LUCILA; TARANTO MARÍA PÍA

Mar del Plata

Congreso; LI Congreso Anual de Investigación Bioquímica y Biología Molecular SAIB; 2015

Sociedad Argentina de Investigación Bioquímica y Biología Molecular

Cobalamin (CBL) is one of the most complex non-polymeric macromolecules synthesized by Eubacteria andArchaea. The biosynthesis de novo of CBL is highly complex and involves about 30 enzymes. We demonstrated thatcell extract of Lactobacillus (L.) coryniformis CRL 1001 is able to correct the coenzyme B12 requirement ofSalmonella Typhimurium AR 2680 (metE-cbiB-) in minimal medium. The aim of this study was to assess the geneticorganization of vitamin B12 biosynthesis in CRL1001 genome and establish its biosynthetic pathway. In silicoanalyzes reveal that this strain possesses a coenzyme B12 gene cluster encoding the gene sets (cbi, cob, and hem) forCBL biosynthesis. Interestingly, CRL 1001 genome lacks cobT. Instead, cblS and cblT, α-ribazole kinase and itstransporter respectively were found. These genes are present in CBL-producer Listeria strains and in L. rossiae DSM15814 but both are absent in L. reuteri CRL 1098, a cobalamin producer. To validate the genetic findings, weinvestigated the CBL synthesis in the presence of key intermediates: DMB (5,6-dimethylbenzimidazole) and L-Thr(Threonine) (separately and together). DMB increases the corrinoid compound production but the higher concentration of CBL was obtained with L-Thr. These results provide valuable evidence of the cobalamin synthesispathway and its regulation in L. coryniformis CRL 1001, a potential probiotic strain.