Impact of nitrogen concentration on validamycin A production and related gene transcription in fermentation of Streptomyces hygroscopicus 5008.

State Key Laboratory of Bioreactor Engineering, School of Biotechnology, East China University of Science and Technology, Shanghai, China,
Bioprocess and Biosystems Engineering (Impact Factor: 1.87). 03/2012; 35(7):1201-8. DOI:10.1007/s00449-012-0707-3
Source: PubMed

ABSTRACT 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.

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