Isolation, identification and characterization of Lactobacillus on black tiger shrimp
Nguyen Phuoc Minh
Shrimp farming has been a significant agro based economic activity. Shrimp farming shows a booming expansion. But thereare also many risks and challenges, especially in theculture techniques, the degradation of environmental quality, biodiversity and natural brood stocks. Pathogenic microorganisms implicated in these outbreaks are viruses, bacteria, algae, fungi and protozoan parasites. The most prevalent bacterial disease is Vibriosis which causes a mass mortality both in larval cultures and shrimp production. In this research we have successfully isolated 5 species of Lactobacillus having ability to compete with 7 species of Vibrio spp. Among 5 species of Lactobacillus having capability to resist with Vibrio spp., we define two Lactobacillus species L1.2 and L1.3 having the strongest resistant capability after 24 hours of cultivation. We have also noticed optimal growing conditions for these Lactobacillus species: L1.2: temperature 37 oC, pH= 6.5 – 7.0, cultivation time to get biomass 24 – 28 h, salinity resistance 5%; L1.3: temperature 34 oC, pH= 6.0 – 7.0, cultivation time to get biomass 20 – 24 h, salinity resistance 5%. Both two species L1.2 and L1.3 have some main characteristics: rod shape, no mobile, lactic acid formation, sugar fermentation (glucose, saccharose, sucrose, mantose, manitol, and sorbitol).