Cashew (Anacardium sp.) is one among the stupendous endowments of the nature having their initial origin in Brazil, South America.According to a popular belief, cashew shifted from Brazil to their colony country, Mozambique in Africa by the Portuguese. Thereafter, the species has seen a massive expansion worldwide. Being a nonclimacteric fruit, cashew apple is bred in three colors: red, yellow, and orange on maturation; while the pulp appears to be pale yellow color irrespective of the outer fruit skin color (Azam-Ali & Judge, 2001;Rocha et al., 2006). Cashew apple juice contains five times of vitamin C as in citrus juice and possesses a juicy structure, with strong astringent flavor. (Akinwale, 2000).The fruit has medicinal properties and can be used for curing scurvy, diarrhea, uterine complaints, cholera, and dropsy and also exhibits anti-mutagenic effects. Ayurveda medicine recommends the

Vitamin B12, a water-soluble vitamin, plays a vital role in regulating metabolism in many organisms. However, its synthesis is restricted to limited bacteria and archaea. Therefore, industrial microbial fermentation is considered as a robust method to meet the demands of the vitamin B12. Lactobacillus reuteri DSM 20016 is one of the vitamin B12 producers. In the present study, liquid paneer whey is used as the medium along with the supplements, glycerol, and cobalt chloride to enhance the vitamin B12 production. The effect of liquid paneer whey, yeast extract, glycerol, and cobalt chloride on the vitamin B12 production was further optimized using Box Behnken design. Under optimized conditions, the production of the vitamin B12 reached up to 213.449 μg.L-1. The current study validated the feasibility of utilizing liquid paneer whey as a medium to produce high yield vitamin B12 by Lactobacillus reuteri DSM 20016.