Short communicationEnhancing vitamin B12 content in soy-yogurt by Lactobacillus reuteri

- Glycerol and fructose were confirmed to enhance the production of vitamin B12.
- Glycerol and fructose induced the expression of cobT and cbiA.
- Glycerol and fructose functioned to balance the redox reaction.
- High content of fructose supplementation suppressed expression of cobT.
- Vitamin B12 content in this soymilk is higher than other fermented soybean food.

More attention from the aged and vegetarians has been paid to soy-product due to its taste, easy digestibility, as well as the association with health. However, soy-product has a defect of low vitamin content, mainly the water-soluble vitamin B12. This study was to investigate co-fermentation of glycerol and fructose in soy-yogurt to enhance vitamin B12 production by Lactobacillus reuteri. After a serial combination experiments, the co-fermentation was confirmed to enhance the production of vitamin B12 up to 18 μg/100 mL. Both supplementations induced the expression of cobT and cbiA and functioned to balance the redox reaction. Meanwhile, high content of fructose supplementation reduced the production of vitamin B12 and suppressed expression of cobT in bacteria. It was proved that the vitamin B12 content of this soy-yogurt is higher than other fermented soybean based food and thus can be served as an alternative food for the aged and vegetarians.