为缓解环磷酸腺苷(cyclic adenosine monophosphate, cAMP)发酵能量供应不足的问题,发酵24 h一次性添加3 g/L-broth的柠檬酸钠,cAMP产量达到3.69 g/L,发酵强度为0.074 g/(L·h),分别比对照提高了11.2%和60.2%,发酵性能得到改善。通过对胞内能量物质含量进行比较,发现添加柠檬酸钠显著提高了ATP含量和ATP/ADP比率,为cAMP合成提供了能量和物质保障。另外,提出了添加柠檬酸钠偶合脉冲补充次黄嘌呤(前体)的发酵工艺,将能量供给与补救途径的优势相结合,cAMP产量达到4.42 g/L,发酵强度为0.088 g/(L·h),分别比对照提高了33.1%和91.3%。
As an auxiliary energy substrate, citrate could enhance the synthesis of ATP and most of the high energy-consuming products. 3 g/L-broth citrate was added into the broth for one time at 24 h for energy supply to produce 3.69 g/L cAMP with the productivity of 0.074 g/(L·h). The performance was improved greatly with cAMP concentration and productivity enhancement of 11.2% and 60.2%, respectively, when compared with control. The results of energy substrate analysis indicated that ATP amounts and ATP/ADP ratios were enhanced notable by sodium citrate. In addition, a cAMP fermentation process with sodium citrate coupling hypoxanthine addition in pulses was proposed and cAMP concentration achieved 4.42 g/L with a productivity of 0.088 g/(L·h), which was improved 33.1% and 91.3%, respectively due to the integrated function of energy supply and salvage pathway.
[1] MCPHEE I, GIBSON L, KEWNEY J, et al. Cyclic nucleotide signalling: A molecular approach to drug discovery for Alzheimer’s disease[J]. Biochemical Society Transactions, 2005, 33(6): 1 330-1 332.
[2] DING Hong, PENG Rui-xin. Role of the cAMP in immunological liver injury in mice: comparing LPS-induced model with LPS+BCG-induced model[J]. Chinese Pharmacology Bulletin, 2003, 19: 940-943.
[3] CHEN Xiao-chun, BAI Jian-xin, CAO Jia-ming, et al. Medium optimization for the production of cyclic adenosine 3’, 5’–monophosphate by Microbacterium sp. no.205 using response surface methodology[J]. Bioresource Technology, 2009, 100(2): 919-924.
[4] 陈晓春. 环磷酸腺苷高产菌的选育及其代谢调控[D]. 南京:南京工业大学, 2010.
[5] CHEN Shuang-xi, CHU Ju, ZHUANG Ying-ping, et al. Enhancement of inosine production by Bacillus subtilis through suppression of carbon overflow by sodium citrate[J]. Biotechnology Letters, 2005, 27(10): 689-692.
[6] CHEN Yong, LI Shu-ya, XIONG Jian, et al. The mechanisms of citrate on regulating the distribution of carbon flux in the biosynthesis of uridine 5’-monophosphate by Saccharomyces cerevisiae[J]. Applied Microbiology and Biotechnology, 2010, 86(1): 75-81.
[7] ZHOU Jing-wen, LIU Long, CHEN Jian. Improved ATP supply enhances acid tolerance of Candida glabrata during pyruvic acid production[J]. Journal of Applied Microbiology, 2011, 110(1): 44-53.
[8] WANG Yu-lei, WANG Da-hui, Wei Gong-yuan, et al. Improved co-production of S-adenosylmethionine and glutathione using citrate as an auxiliary energy substrate[J]. Bioresource Technology, 2012, 131: 28-32.
[9] 徐海,钱卫,季明杰,等. 核苷酸补救途径在肌苷代谢中应用的研究[J]. 山东大学学报, 2000, 35(4): 453-457.
[10] CHEN Xiao-chun, SONG He, FANG Ting, et al. Enhanced cyclic adenosine monophosphate production by Arthrobacter A302 through rational redistribution of metabolic flux[J]. Bioresource Technology, 2010, 101(9): 3 159-3 163.
[11] 曹艳. 利用代谢酶学和模型技术改善谷氨酸发酵的稳定性和糖酸转化率[D]. 无锡:江南大学, 2014.
[12] LI Lei, CHEN Xiao-chun, CHENG Jian, et al. Bi-stage control of dissolved oxygen to enhance cyclic adenosine monophosphate production by Arthrobacter A302[J]. Bioprocess and Biosystems Engineering, 2012, 35(8): 1 281-1 286.
