The biosorption capacity differences of copper cation by yeast Candida utilis cells and isolated cell walls were investigated. The results showed that the metal accumulated by cell walls was usually 50% higher than th...The biosorption capacity differences of copper cation by yeast Candida utilis cells and isolated cell walls were investigated. The results showed that the metal accumulated by cell walls was usually 50% higher than that by intact cells. This suggested that the cell walls of yeast were the main sites for heavy metal accumulation. Treatments of cell wall with proteinases demonstrated that the copper accumulated by trypsin-treated cell walls was almost the same as that by intact cell walls (95%), while the subtilisin-treated cell walls almost lost the potential of metal accumulateion (only 3%), suggesting that the main sites of copper accumulation in Candida utilis cell walls were trypsin-unsensitive integral proteins. Fig 1, Ref展开更多
产朊假丝酵母是生物安全(Generally Recognized as Safe,GRAS)的微生物,也是一种重要的工业微生物。近20年来,随着分子生物学技术的发展,产朊假丝酵母的基因表达系统和基因工程研究及开发应用取得了显著的进展,使得利用该菌表达多种物...产朊假丝酵母是生物安全(Generally Recognized as Safe,GRAS)的微生物,也是一种重要的工业微生物。近20年来,随着分子生物学技术的发展,产朊假丝酵母的基因表达系统和基因工程研究及开发应用取得了显著的进展,使得利用该菌表达多种物质成为可能。本文概述了产朊假丝酵母的生物学特点、外源基因表达系统、基因敲除、遗传转化等方面的研究和应用进展。展开更多
Under the optimal condition of copper ions adsorption on yeast,we found some different effects among static adsorption, shaking adsorption and negative pressure cavitation adsorption, and the methods of yeast with dif...Under the optimal condition of copper ions adsorption on yeast,we found some different effects among static adsorption, shaking adsorption and negative pressure cavitation adsorption, and the methods of yeast with different pretreatments also affect adsorption of copper ions. At the same time, the change of intercellular pH before and after adsorption of copper with BCECF was studied. The copper distribution was located by using PhenGreen （dipotassium salt and diacetate）, and the surface of yeast was observed by an atomic force microscope. The results showed that negative pressure cavitation can improve bioadsorption capacity of copper ions on yeast. However, the yeasts＇ pretreatment has a higher effect on bioadsorption. It indicates that heavy metal bioadsorption on yeast has much relation with its cellular molecule basis. With the adsorping, the intercellular pH of yeast increased gradually and changed from acidity to alkalescence. These results may suggest that negative pressure cavitation can compel heavy metals to transfer from the cell surface into inside cell and make the surface of yeast coarse.展开更多
The growth ofCandida utilis NRRL Y-1084 in acid and enzymatic hydrolysates of cassava peel and on glucose in a mineral salts medium was investigated in aerobic submerged cultivation. Kinetic and stoichiometric paramet...The growth ofCandida utilis NRRL Y-1084 in acid and enzymatic hydrolysates of cassava peel and on glucose in a mineral salts medium was investigated in aerobic submerged cultivation. Kinetic and stoichiometric parameters for growth were determined. The cardinal temperatures of this yeast strain were 14 ℃, 33 ℃ and 41 ℃. C. utilis exhibited no absolute requirement for growth factors, although its maximum specific growth rate （μmax） was higher in the mineral salts medium with yeast extract than without, but its biomass yield coefficient （Yx/s） did not differ much in these two media. In the enzymatic hydrolysate, its Yx/s value on sugar was 0.44 with a μmax of 0.35 h^-1, whereas the corresponding values were 0.52 and 0.48 h^-1 in the acid hydrolysate and 0.50 and 0.37 h^-1 in the mineral salts medium without yeast extract. The crude protein content of biomass grown in the glucose medium and the acid and enzymatic hydrolysates were 47.5%, 49.1% and 56.7%, respectively. The amino acid profile of the yeast biomass compared favourably with the FAO standard. Cassava peel hydrolysate has potential as a cheap carbohydrate feedstock for the production of yeast single cell protein by using C. utilis.展开更多
以蛋白桑桑叶为研究对象,利用产朊假丝酵母菌进行培养料发酵试验。根据单因素试验结果,设计并实施了葡萄糖、磷酸二氢钾(KH2PO4)、硫酸铵[(NH4)_(2)SO_(4)]、硫酸镁(MgSO_(4))、蒸馏水五因素四水平的正交试验,发酵后测定了产朊假丝酵母...以蛋白桑桑叶为研究对象,利用产朊假丝酵母菌进行培养料发酵试验。根据单因素试验结果,设计并实施了葡萄糖、磷酸二氢钾(KH2PO4)、硫酸铵[(NH4)_(2)SO_(4)]、硫酸镁(MgSO_(4))、蒸馏水五因素四水平的正交试验,发酵后测定了产朊假丝酵母菌的菌数,确定了最佳的培养基配方,即1.2 g葡萄糖、0.025 g KH2PO4、0.05 g(NH4)_(2)SO_(4)、0.001 g MgSO_(4)、16 mL蒸馏水。在此培养基中,产朊假丝酵母菌能以菌数多达10.05亿/g进行生长繁殖。展开更多
文摘The biosorption capacity differences of copper cation by yeast Candida utilis cells and isolated cell walls were investigated. The results showed that the metal accumulated by cell walls was usually 50% higher than that by intact cells. This suggested that the cell walls of yeast were the main sites for heavy metal accumulation. Treatments of cell wall with proteinases demonstrated that the copper accumulated by trypsin-treated cell walls was almost the same as that by intact cell walls (95%), while the subtilisin-treated cell walls almost lost the potential of metal accumulateion (only 3%), suggesting that the main sites of copper accumulation in Candida utilis cell walls were trypsin-unsensitive integral proteins. Fig 1, Ref
文摘产朊假丝酵母是生物安全(Generally Recognized as Safe,GRAS)的微生物,也是一种重要的工业微生物。近20年来,随着分子生物学技术的发展,产朊假丝酵母的基因表达系统和基因工程研究及开发应用取得了显著的进展,使得利用该菌表达多种物质成为可能。本文概述了产朊假丝酵母的生物学特点、外源基因表达系统、基因敲除、遗传转化等方面的研究和应用进展。
基金The National Basic Research Program (973) of China (No. 2004CB418505)
文摘Under the optimal condition of copper ions adsorption on yeast,we found some different effects among static adsorption, shaking adsorption and negative pressure cavitation adsorption, and the methods of yeast with different pretreatments also affect adsorption of copper ions. At the same time, the change of intercellular pH before and after adsorption of copper with BCECF was studied. The copper distribution was located by using PhenGreen （dipotassium salt and diacetate）, and the surface of yeast was observed by an atomic force microscope. The results showed that negative pressure cavitation can improve bioadsorption capacity of copper ions on yeast. However, the yeasts＇ pretreatment has a higher effect on bioadsorption. It indicates that heavy metal bioadsorption on yeast has much relation with its cellular molecule basis. With the adsorping, the intercellular pH of yeast increased gradually and changed from acidity to alkalescence. These results may suggest that negative pressure cavitation can compel heavy metals to transfer from the cell surface into inside cell and make the surface of yeast coarse.
文摘The growth ofCandida utilis NRRL Y-1084 in acid and enzymatic hydrolysates of cassava peel and on glucose in a mineral salts medium was investigated in aerobic submerged cultivation. Kinetic and stoichiometric parameters for growth were determined. The cardinal temperatures of this yeast strain were 14 ℃, 33 ℃ and 41 ℃. C. utilis exhibited no absolute requirement for growth factors, although its maximum specific growth rate （μmax） was higher in the mineral salts medium with yeast extract than without, but its biomass yield coefficient （Yx/s） did not differ much in these two media. In the enzymatic hydrolysate, its Yx/s value on sugar was 0.44 with a μmax of 0.35 h^-1, whereas the corresponding values were 0.52 and 0.48 h^-1 in the acid hydrolysate and 0.50 and 0.37 h^-1 in the mineral salts medium without yeast extract. The crude protein content of biomass grown in the glucose medium and the acid and enzymatic hydrolysates were 47.5%, 49.1% and 56.7%, respectively. The amino acid profile of the yeast biomass compared favourably with the FAO standard. Cassava peel hydrolysate has potential as a cheap carbohydrate feedstock for the production of yeast single cell protein by using C. utilis.
文摘以蛋白桑桑叶为研究对象,利用产朊假丝酵母菌进行培养料发酵试验。根据单因素试验结果,设计并实施了葡萄糖、磷酸二氢钾(KH2PO4)、硫酸铵[(NH4)_(2)SO_(4)]、硫酸镁(MgSO_(4))、蒸馏水五因素四水平的正交试验,发酵后测定了产朊假丝酵母菌的菌数,确定了最佳的培养基配方,即1.2 g葡萄糖、0.025 g KH2PO4、0.05 g(NH4)_(2)SO_(4)、0.001 g MgSO_(4)、16 mL蒸馏水。在此培养基中,产朊假丝酵母菌能以菌数多达10.05亿/g进行生长繁殖。
