Lyoprotectants for Lactobacillus brevis B144 and their capability to maintain the expression of surface layer protein

Abstract

Lactobacillus brevis as a probiotic has been reported to facilitate micronutrient absorption such as minerals (zinc, calcium, magnesium) into the intestine through the surface layer protein (Slp). Negatively charged-Slp from the bacteria that adheres on the intestinal mucosa binds to the positively charged-minerals, e.g., calcium, zinc, iron, magnesium and potassium via an ionic interaction. In this study, several sugar-based lyoprotectants (glucose, galactose, and lactose) and skim milk were implemented in the L. brevis B144 InaCC freeze drying. The dried L. brevis B144 InaCC was kept in the refrigerator up to three months and monthly tested for the cell viability. The dried L. brevis B144 InaCC was re-culture and then its Slp was isolated using 8 M guanidine hydrochloride. In general, combinations of skim milk and the sugar-based lyoprotectant provided higher protection than the skim milk alone. Meanwhile, without any lyoprotectant, the L. brevis B144 InaCC lose its ability to grow. In regards to maintain the capability of the Slp expression, the L. brevis B144 InaCC which was protected with the combination of 20% skim milk and 10% galactose showed the highest protein expression level among the other lyoprotectants.