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Partial hydrolysis of triglyceride lipase (Lipase, EC3.1.1.3) enzyme, is an important class of the glycerides of the key enzymes, the catalytic hydrolysis of triglycerides in the oil-water interface to generate fatty acids and glycerol, can also catalyze the synthesis of lipid compounds transesterification. Therefore, the lipase are widely used in the food, pharmaceutical, leather production, detergent, paper-making, environmental protection and many other industries. In recent years, the microbial lipase become the focus of attention with its unique advantages, has been more widely used in industry. Yak milk butter from Tianzhu, Gansu Province, Gannan Pastoral Area the Triton and yak living environment, soil samples were screened production lipase microorganisms, rescreening get a high-yield strains of lipase were identified, and their enzyme production conditions, separation and purification conditions and enzymatic properties were studied. The results showed that: 1. Obtained from the samples collected were screened 10 Lipase Production the microorganisms, rescreening, the strain S122 production lipase activity (39U/mL); the strain S122 colonies were circular planar diffusion, milky white, short velvet-like or nearly powder; morphological identification under the microscope, the bacteria branch, into a single or chain arthrospore arthrospore elongated cylindrical or square, oval or round; under Fungi Manual and identified by 26S rDNA molecules, the genus Geotrichum (Geotrichum LK) the name Geotrichum sp. S122. 2. single factor test strain Geotrichum sp S122 fermentation conditions: temperature, inoculum size, loading amount of fluid , rotation speed, the fermentation period and initial medium pH value were studied; Plackett-Barman and CCD experimental design to optimize the lipase production medium. The results showed that: Geotrichum sp. S122 best enzyme production medium: Sucrose 35.54g / L, peptone 30.00 g / L, 0.50g / L urea, 5.00 g / L, magnesium sulfate 1.00 g of / L, zinc sulfate, sulfite iron 0.50g / L, manganese sulfate 1.02 g of the / L, 1.00 g of the calcium chloride / L, dipotassium hydrogen phosphate 5.00 g / L; optimum fermentation conditions: initial medium pH value of 8.0, the culture temperature of 28 ° C, inoculation amount 4%, the liquid volume 60mL/250mL shaker speed 200r/min, fermentation period 96h. Aqueous two-phase (ATP) extraction method the Geotrichum sp.S122 lipase separation and purification test results show that the concentration of aqueous two-phase system of PEG 10% (the NH 4 ) 2SO4 concentration of 10% NaCI concentration of 2%, the pH value of 5.0, the best extracts, enzyme activity yield of 78%. 4 on of Geotrichum sp.S122 fat Enzymatic Properties showed that the optimum temperature was 30 ° C, the optimum pH value of 5.0; processing of the enzyme at 30 and 40 ° C, the rate of loss of activity is not at 50 and 60 ° C under treatment, enzyme activity loss rate; pH value of 8 to 11 is the most stable enzyme activity, indicating that this enzyme belongs to the medium-temperature alkaline lipase; the the K , Na Zn 2 , the Ca 2 Fe 2 and the Mn 2 different degrees of inhibition of enzyme , Zn 2 strongest inhibition, enzyme activation and the the Mg 2 ion.
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