Isolation of Antimicrobial Probiotic Bacteria from Sour Shrimps in Hue City-Vietnam and Optimization for Biomass and Acid Production

This study isolated antibacterial probiotic strains from sour shrimp, a Vietnamese traditional fermented food, and optimized culturing conditions for the chosen strain. Strain V101 was chosen for optimization experiments for its high antagonistic activity and production of strong antibacterial compounds against indicator harmful bacteria – Escherichia coli, and Staphylococcus aureus. Molecular identification of 16S rRNA sequencing showed that V101 strain was Lactobacillus paracasei. Optimization of culturing conditions found that this strain produces the highest biomass and acid accumulation on modified MRS at pH 5.5; temperature 37 °C in 60 h. Under optimum condition, biomass and acid production increased 76.61% and 10.69% respectively, and antibacterial activities against E. coli improved up to 20%. Pilot fermentation of L. paracasei V101 on production Vietnamese pickles, sour shrimp showed that the fermentation process was quicker, tastier, and fermented products could be preserved longer. These findings will be a potential prerequisite for further study on L. paracasei V101 as a strain not only good for food fermentation and preserving but also a helpful probiotic bacteria bring benefits to human health.