Effects of osmotic pressure and pH on citric acid and erythritol production from waste cooking oil by Yarrowia lipolytica
Effects of osmotic pressure and pH on citric acid and erythritol production from waste cooking oil by Yarrowia lipolytica
复制标题
渗透压和pH值对解脂耶氏酵母利用废弃食用油生产柠檬酸和赤藓糖醇的影响
DOI：
10.1002/elsc.201700114
复制
发表时间：
2018-06-01
影响因子：
2.7
通讯作者：
Xu, Jiming
中科院分区：
文献类型：
--
作者：
Liu, Xiaoyan;Lv, Jinshun;Xu, Jiming
在不同的培养基条件下，解脂耶氏菌可从废食用油中提取赤藓糖醇和柠檬酸，其中渗透压和pH是影响该工艺的关键因素。在高渗透压（2.76 osmol/L）和低pH （pH 3.0）条件下，赤藓糖醇产量最高（21.8 g/L），柠檬酸产量最低（2.5 g/L）。相比之下，在pH为6.0、渗透压为0.75 osmol/L的条件下，柠檬酸的生物合成最高，为12.6 g/L，赤藓糖醇的产量仅为4.0 g/L。此外，对两种培养基的脂肪酶活性进行了检测，认为pH 3.0-OP 2.76对脂肪酶活性更有利。随后研究了赤藓糖醇和柠檬酸生物合成的生化途径，并认为WCO的产物与转酮醇酶、红细胞还原酶、柠檬酸合成酶和甘油激酶的活性有关。然而，RT - PCR分析显示，这些酶的mRNA水平没有显著差异，证实了赤藓糖醇和柠檬酸的代谢通量调节主要发生在转录后水平。
Erythritol and citric acid could be produced from waste cooking oil (WCO) by Yarrowia lipolytica under different medium conditions, and osmotic pressure together with pH were considered to be the critical factors in this process. High osmotic pressure (2.76 osmol/L) combined with low pH (pH 3.0) promoted the highest yield of erythritol (21.8 g/L) accompanied by low‐producing citric acid (2.5 g/L). By contrast, the highest citric acid biosynthesis (12.6 g/L) was detected under a pH of 6.0 and an osmotic pressure of 0.75 osmol/L, when only 4.0 g/L of erythritol was yielded. Moreover, lipase activities in these two media were also detected, and pH 3.0–OP 2.76 was supposed to be more beneficial to lipase activity. Biochemical pathways involved in the biosynthesis of erythritol and citric acid were subsequently investigated, and the products yielded from WCO were assumed to be correlated with the activities of transketolase, erythrose reductase, citrate synthase, and glycerol kinase. However, RT‐PCR analysis revealed that mRNA levels of these enzymes did not significantly differ, confirming that metabolic flux regulations of erythritol and citric acid mostly took place at the post‐transcriptional level.