Strain CG-9, isolated from human saliva and identified as Enterococcus faecalis, produced a component that inhibits the growth of Gram-positive and Gram-negative bacteria. The active peptide from the cell-free supernatant of Enterococcus faecalis CG-9 was purified in three steps: (1) precipitation with 70% saturated ammonium sulfate: (2) cation-exchange chromatography, (3) gel filter chromatography. The purified bacteriocin exhibited a wide range of antimicrobial activity against many food-borne spoilage and Pathogenic bacteria such as Escherichia coli, Listeria monocytogenes, Staphylococcus aureus, as well as some yeast. The bacteriocin was heat stable, pH resistant and protease sensitive. Ethylenediaminetetraacetic acid, sodium dodecyl sulfate, Tween 80 and 6% sodium chloride did not decrease the activity. The characterization, antimicrobial spectrum and molecular mass of this bacteriocin suggested that it was a novel bacteriocin with potential research and application value in food industry.

Bacillus subtilis HLZ-68 can produce L-amino acid oxidase (L-AAO), and DL-arginine can be degraded asymmetrically by suspending the wet bacterial biomass in the degradation liquid. By adding oxygen-vectors to the fermentation medium, the collected amount of wet bacterial biomass can be increased. Taking n-dodecane, n-hexadecane, oleic acid, paraffin and n-hexane as oxygen-vectors, the optimal oxygen-vector was 1.2% (v/v) oleic acid. The wet weight biomass increased by 66.83% and the activity of L-AAO in the fermentation broth increased by 38.88% compared with those before the addition of oxygen-vector. The standard sample DL-arginine was derivatized by phenyl isothiocyanate, and then subjected to high-performance liquid chromatography (HPLC), and the obtained peak area and arginine content were used as standard curves to measure the DL-arginine. The content of D-arginine and L-arginine in the initial degradation solution was 50% each, and the bacterial cells were added to the initial degradation solution of DL-arginine. After 21 h of reaction, L-arginine was completely degraded, leaving 47% of Darginine. D-alanine was easily extracted from the reaction solution using cation-exchange resin, after centrifugation, decolourization, concentration and vacuum drying, and the chemical and optical purity of the extracted D-arginine were 92.68% and 97.46%, respectively.

The Bacillus subtilis H-8 independently screened by our laboratory can produce L-amino acid oxidase (L-AAO), and DL-arginine can be degraded asymmetrically by suspending the wet bacteria in the degradation liquid. By adding oxygen-vectors to the fermentation medium, the collected amount of wet bacteria can be increased. Taking n-dodecane, n-hexadecane, oleic acid, paraffin, and n-hexane as oxygen-vectors, the optimal oxygen-vector oleic acid was 1.2% (v/v). The weight of wet cells increased by 66.83% compared with before, and the activity of L-AAO in fermentation broth increased by 38.88% compared with before. The standard sample DL-arginine was derivatized by phenyl isothiocyanate, and then subjected to high performance liquid chromatography(HPLC), and the obtained peak area and arginine content were used as standard curves to measure the DL-arginine. The content of D-arginine and L-arginine in the initial degradation solution was 50% each, and the bacterial cells are added to the initial degradation solution of DL-arginine. After 21 hours of reaction, L-arginine was completely Degraded, remaining 47% of D-arginine.D-alanine was easily extracted from the reaction solution using cation-exchange resin,after centrifugation, decolorization, concentration and vacuum drying, and the chemical and optical purity of the extracted d-alanine was 92.68 and 97.46%, respectively.

The Bacillus subtilis HLZ-68 independently screened by our laboratory can produce L-amino acid oxidase (L-AAO), and DL-arginine can be degraded asymmetrically by suspending the wet bacteria in the degradation liquid. By adding oxygen-vectors to the fermentation medium, the collected amount of wet bacteria can be increased. Taking n-dodecane, n-hexadecane, oleic acid, paraffin, and n-hexane as oxygen-vectors, the optimal oxygen-vector oleic acid was 1.2% (v/v). The weight of wet cells increased by 66.83% compared with before, and the activity of L-AAO in fermentation broth increased by 38.88% compared with before. The standard sample DL-arginine was derivatized by phenyl isothiocyanate, and then subjected to high performance liquid chromatography(HPLC), and the obtained peak area and arginine content were used as standard curves to measure the DL-arginine. The content of D-arginine and L-arginine in the initial degradation solution was 50% each, and the bacterial cells are added to the initial degradation solution of DL-arginine. After 21 hours of reaction, L-arginine was completely Degraded, remaining 47% of D-arginine.D-alanine was easily extracted from the reaction solution using cation-exchange resin,after centrifugation, decolorization, concentration and vacuum drying, and the chemical and optical purity of the extracted d-alanine was 92.68 and 97.46%, respectively.