Effects of Trace Elements on Growth and Acetate Production of Escherichia coli
微量元素对大肠杆菌生长和乙酸生成的影响研究

The metabolic characteristics of Escherichia coli DA19 were affected by the trace elements added in the minimal medium. When cultured in the minimal medium with an initial NH 4 + concentration of 17.4 mmol/L, both growth and cell yield based on consumed glucose were improved and less acetate was produced as a mixture of trace elements was added, and NH 4 + became a limiting nutrient at glucose concentration higher than 5.45g/L. When cultured in the minimal medium with sufficient nitrogen source (57.5 mmol/L of NH 4 +), addition of trace elements resulted in a great increase in cell growth and glucose consumption. The cell yield based on consumed glucose increased by at least 60% while produced acetate was only 13% of those obtained in medium without the addition of trace elements. The amount of added trace elements mixture, ranging from 0.1 to 1 mL/L, had almost the same effects on cell growth, acetate production and glucose consumption. Al 3+ had negative effects on the growth and glucose utilization while Co 2+ , Mn 2+ or Fe 2+ respectively improved growth and reduced acetate production. On the other hand, BO 3 3- , Zn 2+ , MoO 4 2+ , or Cu 2+ almost had no significant effects on the metabolic activities of DA19. In the medium supplemented with Fe 2+ , the behavior of the culture of DA19 was almost the same as that in medium supplemented with the trace element mixture.