Studies On Marine Lysozyme From Bacillus Ceceus S-12-86

Bacteria S-12 possessing high lytic activity against bacteria which is resistant to egg-white lysozyme was isolated from sea mud by plate containing intact cells of Staphylococcus aureus. Morphological, cultural, physiological properties, IGSrDNA sequences were researched. Based on the test results, and S-12 was classified into Bacillus ceceus.Taking the Bacillus cereus S-12 as the initial strain, under the optimum condition of formation and regeneration, protoplasts of the strain were prepared, which underwent mutagenic treatments of protoplasts. After selecting from large amount of the regenerate mutants, a stable mutant S-12-86 producing high-output lysozyme was obtained. The strain can produced large amount of enzyme in tap water medium, with enzyme activity being increased to 270U/ml, which made it possible for low-temperature lysozyme from Bacillus cereus S-12-86 to solve the problem, which made it large-scale production and to break the limitation of industrial region.The optimization test concerning the fermentation conditions, such as carbon sources, nitrogen sources, initial pH, culture time, inoculum size, inoculating time etc., is conducted, with the culture strain Bacillus cereus S-12, the mutant of S-12-86. The result of the experiment shows that the optimum lysozyme producing activity is reached after 2h of culturing in a rotary shaker (250r/min) at 25癈, with carbon source of 2% dextrin and 2% peanut powder: nitrogen source of 1% NH4CL and 1% (NH4)2S04, initial pH of 7; inoculum of 6% cultured for 20h.The study on the physical and chemical properties and Inhibitory ability of a marine bacterium is conducted. The optimum temperature of the Lysozyme reacting to Micrococcus lysodleikticus is 35癈, the optimum pH is 8. 5. The marine can keep high activity at low - temperature and has broad - spectrum antibiotic reaction, which may kill gram-positive or gram-negative germs and epiphyte. The study on Inhibitory ability indicates: The enzyme activity is stable, effects of metal ions . It copes well with regular cosmetic powder ingredients.