Production and preparation of organic zinc enriched Lactobacillus fermentum SR4 biomass containing dahi

Abstract

In the present study Lactobacillus fermentum SR4 was used for biotransformation of inorganic zinc into organic form. L. fermentum SR4 was grown in MRS medium supplemented with 200 ppm zinc sulphate under optimized conditions. The bacterial cells adsorbing organic zinc were harvested by centrifugation and subjected to ultra-sonication. The bacterial lysate obtained by ultrasonication contained 1.69 mg/g of zinc on dry weight bases. The bacterial lysate containing 15 ppm of zinc was added into milk just before inoculation of the culture. Zinc enriched dahi was prepared with S. thermophilus NCDC 074 and Lactobacillus rhamnosus NCDC 610 singly and in combinations. Among the various combinations used zinc enriched Dahi made by S. thermophilus NCDC 074 and Lactobacillus rhamnosus NCDC 610 in 1:1 ratio showed better technological and microbiological quality.