Impact of nitrogen concentration on validamycin A production and related gene transcription in fermentation of Streptomyces hygroscopicus 5008
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Validamycin A (VAL-A) is an important and widely used agricultural antibiotic. In this study, statistical screening designs were applied to identify significant medium variables for VAL-A production and to find their optimal levels. The optimized medium caused 70% enhancement of VAL-A production. The difference between optimized medium and original medium suggested that low nitrogen source level might attribute to the enhancement of VAL-A production. The addition of different nitrogen sources to the optimized medium inhibited VAL-A production, which confirmed the importance of nitrogen concentration for VAL-A production. Furthermore, differences in structural gene transcription and enzyme activity between the two media were assayed. The results showed that lower nitrogen level in the optimized medium could regulate VAL-A production in gene transcriptional level. Our previous study indicated that the transcription of VAL-A structural genes could be enhanced at elevated temperature. In this work, the increased fermentation temperature from 37 to 42 °C with the optimized medium enhanced VAL-A production by 39%, which testified to the importance of structural gene transcription in VAL-A production. The information is useful for further VAL-A production enhancement.
KeywordsValidamycin A Gene transcription Secondary metabolites Nitrogen source
We appreciate the financial support from the National 863 High Technology Program (Project # 2006AA10A202) of the MOST and the National Natural Science Foundation of China (NSFC project No. 30821005). JJZ also appreciates the National 985 Project and the University Distinguished Professorship program (SJTU).
- 13.Kieser T, Bibb MJ, Chater KF, Butter MJ, Hopwood DA (2000) Practical Streptomyces genetics: a laboratory manual. John Innes Foundation, Norwich, pp 342–453Google Scholar
- 14.Deutsch J (1983) Glucose-6-phosphate dehydrogenase, 3rd edn., Methods of enzymatic analysisVerlag Chemie, Germany, pp 191–197Google Scholar
- 15.Li JH, Liu L, Fang J, Du GC, Chen J (2009) Statistical modeling and optimization for enhanced whole-cell biotransformation synthesis of 2-O-alpha-d-glucopyranosyl-l-ascorbic acid from maltose and l-ascorbic acid by Aspergillus niger capable of producing alpha-glucosidase. J Biosci Bioeng 108:26–127CrossRefGoogle Scholar