Polyphasic Taxonomy Of A Lysozyme-producing Marine Bacteria S-12-86 And Studies On The Characteristics And Application Of The Lysozyme

One marine bacteria strain S-12-86 is isolated from a sea mud sample collected from the East China Sea. Based on its morphology, physiological and biochemical characteristics and 16S rDNA sequence analysis, it is proposed as a new subspecies of genus Brevibacillus and named as Brevibacillus laterospore subsp. eastchinaseaensis.Antimicrobial action of marine microbial lysozyme on the Gram-negative bacteria, Gram-positive bacteria and fungi is studied experimentally. The results show that the antimicrobial spectrum of marine lysozyme is wide and it has various degrees of inhibitory effects upon the tested strains, especially high activity on the clinical isolates and pathogenic germs in aquaculture. The marine lysozyme has influences on the growth and metabolization of tested strains and the inhibition occurs at the beginning of the exponential phase of growth. Observation under transmission electron microscope reveals that marine lysozyme has different effects on Escherichia coli and Staphylococcus aureaus. Maybe the antimicrobial mechanism of marine lysozyme to Escherichia coli and Staphylococcus aureaus is different mainly due to their different structures of cell wall.The marine lysozyme has many unique advantages compared with the lysozyme from chicken egg white and various animals, vegetables and microorganisms. The optimum temperature of marine lysozyme is low, the stability is good and it has a broad spectrum against both Gram-positives and Gram-negatives, which are resistant to egg white lysozyme, especially high activity is shown to many pathogenic germs. Lysozymes from different sources have different properties, and then the combination of different lysozymes will increase their field of application due to their co-operation action.When the level of addition is 0. 2‰-0. 3‰ in the turbot diet, marine lysozyme can help turbot inhibiting the growth of bacteria, preventing diseases, accelerating its growth, exalting animal diet efficiency and increasing condition, etc. As the animal feed additive or the water body disinfectant, marine lysozyme can increase the immunity, strength the resistibility to the bacteria or virus, and raise survival rate of Fenneropenaeus chinensis.