强化供氧对巴氏醋杆菌醋酸发酵及胞内ATP浓度的影响

摘要

The effects of dissolved oxygen on acetic acid fermentation of Acetobacter pasteurianus is significant.But the mechanism of effects of dissolved oxygen on acetic acid fermentation is not very clear.By improving the agitation speed,the mechanism of effects of strengthening oxygen supply on acetic acid fermentation of Acetobacter pasteurianus is researched in this paper.The experimental results show that the intracellular ATP concentration is increased by 302% and the enzyme activities of ADH,ALDH and ATPase in alcohol respiratory chain energy metabolism are increased by 40%,60% and 56% respectively when the agitation speed increases from 500 r/min to 700 r/min.Moreover,compared with the agitation speed of 500 r/min to 700 r/min,the bacteria concentration,acetic acid concentration and acetic acid production of unit cell are increased by 37%,150% and 84% respectively when fermentation time is 28 h.From this we can know that large amount of dissolved oxygen is consumed in the process of bacterial growth and acetic acid production of Acetobacter pasteurianus,especially when the acetic acid production reaches the maximum in 16~28 h.When strengthening the oxygen supply by increasing the agitation speed,the enzyme activities of key enzymes in alcohol respiratory chain energy metabolism of Acetobacter pasteurianus are significantly improved. Also the acid production of ethanol oxidation and the energy production by alcohol respiratory chain are strengthened.Therefore,it can provide more energy for bacterial growth and acetic acid production of Acetobacter pasteurianus,it also meets the energy needs for the rapid growth of bacteria and adapts to the high acetic acid living environment,and it improves the tolerance of bacteria to acetic acid.So the bacteria concentration and acetic acid production rate are increased.%溶氧对巴氏醋杆菌醋酸发酵有显著影响,但是目前溶氧对醋酸发酵影响的机理尚不十分清楚,文章通过提高搅拌转速,探讨强化供氧对巴氏醋杆菌醋酸发酵影响的机理.研究结果显示:搅拌转速从500 r/min增加到700 r/min后,胞内ATP浓度提高了302%;乙醇氧化偶联呼吸链产能途径关键酶ADH,ALDH和ATPase 酶活性分别提高了40%,60%和56%.当发酵28 h时,转速700 r/min与500 r/min相比菌体浓度提高了37%,产酸量提高了150%,单位菌体产酸提高了84%.由此可知,巴氏醋杆菌菌体生长和醋化乙醇过程中需要消耗大量的溶氧,尤其在16~28 h产酸高峰期对溶氧的消耗更大.提高搅拌转速强化供氧可显著提高巴氏醋杆菌乙醇氧化偶联呼吸链产能途径关键酶的活性,强化乙醇氧化产酸和乙醇呼吸链途径产能,为巴氏醋杆菌菌体生长和产酸提供更多的能量,满足菌体快速生长和适应高酸生存环境对能量的需求,提高菌体对醋酸的耐受性,从而提高菌体浓度和产酸速率.