L-Lysine was produced by a microbial process utilizing a Corynebacterium glutamicum （ATCC 21799） strain. L-Lysine was purified from the cultivated medium by fixed-bed and simulated moving bed （SMB） chromatography....L-Lysine was produced by a microbial process utilizing a Corynebacterium glutamicum （ATCC 21799） strain. L-Lysine was purified from the cultivated medium by fixed-bed and simulated moving bed （SMB） chromatography. The separation conditions including pH, eluent concentration and Lys+ and Lys2+ adsorption isotherms were studied in batch adsorption. The column capacity, eluent flow rate and eluent concentration have been studied in fixed-bed chromatography. Maximum purification rate of lysine was obtained as 0.066 （g/（g·h）） （per gram resin and per hour） at an eluent flow rate of 10 （mL/min） in fixed-bed chromatography. The results obtained from SMB were 0.11 （g/（g·h）） for L-lysine purification rate and 96% for L-lysine recovery.展开更多
An antithrombus enzyme (ATE) was precipitated by (NH4)2SO4 or ethanol from supernatant of Bacillus subtilis culture broth then purified using ion exchange chromatography on CM-sepharose fast flow. The effects of ionic...An antithrombus enzyme (ATE) was precipitated by (NH4)2SO4 or ethanol from supernatant of Bacillus subtilis culture broth then purified using ion exchange chromatography on CM-sepharose fast flow. The effects of ionic strength and pH value on protein adsorption, the gradient elution at different flow rates and step elution were examined respectively. The recovery yield of the optimised process was 74.5% with a purification factor 8.1. The ATE molecular weight was estimated as 30ku by SDS-PAGE. The experimental results showed that the enzyme was stable in the range of pH 7 to pH11, and temperature 25℃ to 37℃.展开更多
Acetylcholinesterase （ACHE） plays an important role in enzyme-based detection of pesticides in the environment. In this paper, ACHE from the Triton X-100 extract of brain tissues of Oreochromis aurea was purified by...Acetylcholinesterase （ACHE） plays an important role in enzyme-based detection of pesticides in the environment. In this paper, ACHE from the Triton X-100 extract of brain tissues of Oreochromis aurea was purified by （NH4）2SO4 fractional precipitation, Sephadex G-100 gel filtration, and DEAE-cellulose ion exchange chromatography. Certain biochemical characterizations of the purified enzyme and inhibition of pesticides on the enzyme were also studied. The specific activity of this purified enzyme was 20.628 U/mg protein, fold of purification was 139, and recovery was 22.1%. The optimal temperature of this enzyme was between 35-40 ℃, and optimal pH was between 7.5-8.0. The Michaelis constant （Kin） for acetylthiocholine iodide was 0.183 mmol/L. The enzyme activity was inhibited by excess substrate, and optimal substrate concentration was 6 mmol/L. Four pesticides （dichlorvos, phoxim, triazophos, and methomyl） exhibited strong inhibitions on this enzyme with IC50 less than 5 μg/mL. This study suggests that Oreochromis aurea （tilapia） could be a good enzyme source for pesticide monitoring in water environments.展开更多
Bacteriocins are a large group of chromosome or plasmid-encoded and ribosomally synthesized low-molecular-weight (2 to 6 kDa) antimicrobial and amphiphilous peptides produced by Gr+ or Gr- bacteria [1]. Their low toxi...Bacteriocins are a large group of chromosome or plasmid-encoded and ribosomally synthesized low-molecular-weight (2 to 6 kDa) antimicrobial and amphiphilous peptides produced by Gr+ or Gr- bacteria [1]. Their low toxicity as well as the absence of allergenicity and reactogenicity is confirmed by testing selected bacteriocins [2] [3]. Bacteriocins can be widely used as preservatives and antibiotic alternatives in medicine. Nisin, a Streptococcus lactis-derived bacteriocin, has been in practice in food industry for a long time. A relevant product contains about 2.5% of nisin. For medical use (e.g., when injected into the blood stream), highly purified drugs are required. However, the yield of bacteriocins accounts for no more than a few percents from the total activity in the culture liquid. In this paper, we propose methods (by example of two B. subtilis strains), allowing to increase the yield up to ~80%. It is believed that other bacteriocins may be purified by these methods and with the same yield.展开更多
Choleragenoid was obtained in pure form by ultra-filteration and fractionation on cationexchange resin-phospho-cellulose column. The choleragenoid was highly pure as judged by the electrophoresis of isoelectric focusi...Choleragenoid was obtained in pure form by ultra-filteration and fractionation on cationexchange resin-phospho-cellulose column. The choleragenoid was highly pure as judged by the electrophoresis of isoelectric focusing,immunization and SDS-gel electrophoresis.The results of test are thesame as that of the standard choleragenoid.展开更多
文摘L-Lysine was produced by a microbial process utilizing a Corynebacterium glutamicum （ATCC 21799） strain. L-Lysine was purified from the cultivated medium by fixed-bed and simulated moving bed （SMB） chromatography. The separation conditions including pH, eluent concentration and Lys+ and Lys2+ adsorption isotherms were studied in batch adsorption. The column capacity, eluent flow rate and eluent concentration have been studied in fixed-bed chromatography. Maximum purification rate of lysine was obtained as 0.066 （g/（g·h）） （per gram resin and per hour） at an eluent flow rate of 10 （mL/min） in fixed-bed chromatography. The results obtained from SMB were 0.11 （g/（g·h）） for L-lysine purification rate and 96% for L-lysine recovery.
文摘An antithrombus enzyme (ATE) was precipitated by (NH4)2SO4 or ethanol from supernatant of Bacillus subtilis culture broth then purified using ion exchange chromatography on CM-sepharose fast flow. The effects of ionic strength and pH value on protein adsorption, the gradient elution at different flow rates and step elution were examined respectively. The recovery yield of the optimised process was 74.5% with a purification factor 8.1. The ATE molecular weight was estimated as 30ku by SDS-PAGE. The experimental results showed that the enzyme was stable in the range of pH 7 to pH11, and temperature 25℃ to 37℃.
基金supported by Huizhou Science and Technology Planning Project Foundation (Grant No.2008P60)
文摘Acetylcholinesterase （ACHE） plays an important role in enzyme-based detection of pesticides in the environment. In this paper, ACHE from the Triton X-100 extract of brain tissues of Oreochromis aurea was purified by （NH4）2SO4 fractional precipitation, Sephadex G-100 gel filtration, and DEAE-cellulose ion exchange chromatography. Certain biochemical characterizations of the purified enzyme and inhibition of pesticides on the enzyme were also studied. The specific activity of this purified enzyme was 20.628 U/mg protein, fold of purification was 139, and recovery was 22.1%. The optimal temperature of this enzyme was between 35-40 ℃, and optimal pH was between 7.5-8.0. The Michaelis constant （Kin） for acetylthiocholine iodide was 0.183 mmol/L. The enzyme activity was inhibited by excess substrate, and optimal substrate concentration was 6 mmol/L. Four pesticides （dichlorvos, phoxim, triazophos, and methomyl） exhibited strong inhibitions on this enzyme with IC50 less than 5 μg/mL. This study suggests that Oreochromis aurea （tilapia） could be a good enzyme source for pesticide monitoring in water environments.
文摘Bacteriocins are a large group of chromosome or plasmid-encoded and ribosomally synthesized low-molecular-weight (2 to 6 kDa) antimicrobial and amphiphilous peptides produced by Gr+ or Gr- bacteria [1]. Their low toxicity as well as the absence of allergenicity and reactogenicity is confirmed by testing selected bacteriocins [2] [3]. Bacteriocins can be widely used as preservatives and antibiotic alternatives in medicine. Nisin, a Streptococcus lactis-derived bacteriocin, has been in practice in food industry for a long time. A relevant product contains about 2.5% of nisin. For medical use (e.g., when injected into the blood stream), highly purified drugs are required. However, the yield of bacteriocins accounts for no more than a few percents from the total activity in the culture liquid. In this paper, we propose methods (by example of two B. subtilis strains), allowing to increase the yield up to ~80%. It is believed that other bacteriocins may be purified by these methods and with the same yield.
文摘Choleragenoid was obtained in pure form by ultra-filteration and fractionation on cationexchange resin-phospho-cellulose column. The choleragenoid was highly pure as judged by the electrophoresis of isoelectric focusing,immunization and SDS-gel electrophoresis.The results of test are thesame as that of the standard choleragenoid.
