The present invention is directed to a system and method for producing vitamin B12 enriched Duckweed Bacterial Culture (DBC) composition. The aforementioned method comprises steps of inoculating at least one Lemnoideae species and at least one vitamin B12 producing bacteria species in a volume of growth media; incubating said at least one Lemnoideae species and said at least one vitamin B12 producing bacteria species under predetermined conditions to provide a Duckweed-Bacterial Culture (DBC); determining time intervals within said plots characterized by DBC with highest vitamin B12 content; and harvesting said DBC at said predetermined time intervals, thereby providing vitamin B12 enriched DBC composition. The present invention further discloses a composition comprising a vitamin B12 enriched Duckweed-Bacterial Culture (DBC), wherein said composition comprises at least one Lemnoideae species and at least one B12 producing bacteria species, further wherein said vitamin B12 content in said composition is in the range of between about 0.01 and about 100 μg per 100 g of said DBC.