. "The chemical reactions and pathways resulting in the formation of cobalamin (vitamin B12) in the absence of oxygen." . . "anaerobic cobalamin biosynthetic process" . "anaerobic cobalamin anabolism" . "anaerobic cobalamin biosynthesis" . "anaerobic cobalamin formation" . "anaerobic cobalamin synthesis" . "anaerobic vitamin B12 biosynthesis" . "anaerobic vitamin B12 biosynthetic process" . "cobalamin biosynthesis, anaerobic" . "cobalamin biosynthetic process, anaerobic" . "vitamin B12 biosynthesis, anaerobic" . "vitamin B12 biosynthetic process, anaerobic" . . .