Standardization of lyophilization medium for Streptococcus thermophilus subjected to viability escalation on freeze drying

Abstract

The objective of the present study is to develop a lyophilization medium for Streptococcus thermophilus (NCIM 2904) as the industrial exploitation of this bacterium totally depends upon preservation and lyophilization protocols. Protective effect of 18 compounds were observed individually and in combinations with different sugars, sugar alcohols, polymers, protein concentrates and buffers. Among all the protectants tested, ammonium citrate (1% w/w), K 2 HPO 4 (1% w/w) and KH 2 PO 4 (1% w/w) provided lowest protection to these bacterial cells while 10% (w/w) sodium caseinate, whey protein concentrate, sweet whey powder, and skim milk showed significant results in viability escalation. Survival in carbon sources like lactose, sucrose and maltodextrine was also favored maximally. Combination of sodium caseinate 10%, skim milk 5%, sucrose 5%, lactose 5% and mono sodium glutamate 1% in distilled water in ratio of 1:5 with S. thermophilus showed survival percentage of 96%.

Biofertilizers: An ecofriendly technology for nutrient recycling and environmental sustainability

“…Sodium glutamate makes the cell membrane more fluid by stabilizing the headgroups and it influences the membrane conservation and also increases the bacterial resistance to drying ( Martos et al, 2007 ). Further, amino groups of milk proteins react with the amino groups of carrier molecules, thus stabilizes the protein structure ( Sharma et al, 2014 ). Like glycerol and maize bran residue, whey is also a cheap compound, which serves as additional nutrient as well as protectant ( Vassilev et al, 2017 ; Zhang et al, 2018 ).…”

Lyophilized Probiotic Lactic Acid Bacteria Viability in Potato Chips and Its Impact on Oil Oxidation

“…Lyophilization can cause many negative effects on the cells, such as a disruption of the cell walls resulting from the water vapor transportation to the surface of the sample for sublimation, collapse of protein and shrinkage [31]. Sharma et al [50] reported skim milk as cryoprotectant for Streptococcus thermophilus strain. However, for Lactobacillus strains lyophilization, Yeo et al [44] recommended a mix of 10% skim milk and 10% sucrose with 2.5% sodium glutamate.…”

Evaluation of microbiota-induced changes in biochemical, sensory properties and volatile profile of kombucha produced by reformed microbial community

“…The effectiveness of lyophilization was calculated by the microbial survival rate (Eq. 2) ( Sharma et al, 2014 ). Serial dilutions of lyophilized cultures were prepared in 1:10 physiological saline solution (0.86% NaCl) for this purpose.…”