胞外初始底物浓度对产氢光合细菌葡萄糖跨膜传输及代谢的影响

Effect of Initial Glucose Concentration on Glucose Transmembrane Transportation and Metabolism of Hydrogen-Producing Photosynthetic Bacteria

对产氢光合细菌葡萄糖跨膜传输速率、葡萄糖酶酵解速率进行了实验研究,对胞内葡萄糖浓度、葡萄糖传输渗透系数进行了计算.实验结果表明,胞外初始底物浓度为50～100mmol/L时,葡萄糖传输速率、胞内葡萄糖浓度总体都随胞外初始底物浓度的增大而增大,但胞外初始底物浓度增大至150mmol/L时,对葡萄糖跨膜传输产生了限制作用,葡萄糖传输速率和胞内葡萄糖浓度均相应减小;计算得到胞内葡萄糖浓度最小值为0.34mmol/L,最大为5.87mmol/L;初始底物浓度为15～35mmol/L时,细胞破碎液葡萄糖酶酵解速率随底物浓度的增大而增大;胞外初始底物浓度为50～150mmol/L时,葡萄糖代谢速率受葡萄糖传输速率控制,产氢光合细菌葡萄糖平均渗透系数为231.13cm3h-1g(DW)-1,葡萄糖传输速率主要受胞内外葡萄糖浓度势差控制;75mmol/L为较有利于葡萄糖跨膜传输的最佳胞外初始底物浓度.

The glucose transmembrane transportation rate and glucose glycolysis rate of hydrogen-producing photosynthetic bacteria were investigated,and the intracellular glucose concentration and permeability coefficient of glucose transportation were calculated in this study.The experimental results showed that both the glucose transportation rate and intracellular glucose concentration increased with increasing of extracellular initial glucose concentration which ranged between 50～100 mmol/L,while decreased due to glucose transport limitation when the extracellular initial glucose concentration further increased to 150 mmol/L.The minimum and maximum intracellular glucose concentrations in the experiments were 0.34 mmol/L and 5.87 mmol/L,respectively.For the extracellular initial concentration with a range between 50 and 150 mmol/L,the glucose metabolism rate of the photosynthetic bacteria was controlled by the glucose transport process where the average glucose permeability coefficient was 231.13 cm^3 h^-1 g（DW）^-1.It was found that 75 mmol/L was the best extracellular initial glucose concentration for the glucose transmembrane transportation process.Fig 5,Ref 11