摘要
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. 088g/(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 improved33. 1% and 91. 3%,respectively due to the integrated function of energy supply and salvage pathway.
引文
[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 c AMP 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 adenosine3’,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 mecha-nisms 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):3159-3 163.
[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):1281-1 286.