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Mi Sun

Publications and source records attributed to Mi Sun.

2 recordsLinked to original sources

[Purification and characterization of a lysozyme from a marine microorganism].

A novel lysozyme was purified from a marine microorganism and its major characteristics were studied. Cell-free supernatant was prepared by centrifugation of culture broth, ultrafiltration using a hollow fiber (molecular weight cut off, 50kD) and concentration using a hollow fiber (molecular weight cut off, 10kD). The crude lysozyme was purified 34.7 fold to electrophoretic homogeneity with a recovery of 24.1% by CM-Sepharose FF cationic-exchange and Sephadex G-100 gel chromatography. The relative molecular weight of this lysozyme was determined as about 39 kD. The optimum pH and temperature towards Micrococcus lysodleikticus were pH 8.0 and 35 degrees C respectively, and the enzyme was stable at temperature below 50 degrees C and pH 5.0 - 10.0. The lysozyme activity was slightly enhanced by Zn2+ and Cu2+ and slightly inhibited by Mn2+ and Ag+. The lysozyme showed good compatibility to many common chemical agents such as EDTA (0.1%) and KH2 PO4 (1.0%). The lysozyme had broad-spectrum against many bacteria, including a number of pathogens, which were resistant to egg-white lysozyme.

Bacterial Proteins↗

[Study on low-temperature alkaline lipase from Bohaisea-9145].

Lipase-overproducing marine yeast Bohaisea-9145 isolated from the Bohai sea region was identified as psychrotrophlic Yarrowia lipolytica. The optimum composition of culture medium was ground soybean 4%, rice bran 4%, peanut power 4%, crude peanut oil 0.5%, MgSO4 0.05%, KH2PPO4 0.2%. The optimum temperature and pH were 26 +/- 1 degrees C pH5.0, the time of fermentation cycle was 23h. The lipase activity was improved to 258.67 U/mL through optimization, four-fold more than that of initial strain. The lipase displayed maximum activity at pH 8.5, 35 degrees C and was stable within the range of pH 4.0 - 9.0 at low temperature. It had high thermosensitivity, good compatibility with familiar metal ions and chemical reagents. It was antioxidant and had strong resistance to high salinity. As a novel marine low-temperature lipase, it has promising prospect in many fields, especially as an additive of detergent.

Lipase↗