Application of Microbioassay of Vitamin B₁₂ Using Lactobacillus leichmannii to Sea Water

Abstract

As for a microbioassay of the vitamin B₁₂ by Lactobacillus leichmannii (ATCC 7830) an influence by salt is serious. Before desalt processing of samples should be done, when the measurement of vitamin B₁₂ in the sea water is done by the microbioassay. The method that vitamin B₁₂ was measured by the microbioassay after desalt processing by Bond-Elut^® was examined. First of all, vitamin B₁₂ was absorbed to Bond-Elut^®. The vitamin B₁₂ that was absorbed was extracted with 40% ethanol. This extract was measured with the microbioassay. An addition of KCN to samples was indispensable due to the stabilization of vitamin B₁₂. The coefficient of variation of this analysis method was 5.315.9%. In this method, the recovery of vitamin B₁₂ ranged from 92.7 to 116%.