title: Impact of nitrogen concentration on validamycin A production and related gene transcription in fermentation of Streptomyces hygroscopicus 5008.
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.
authors.affiliation: State Key Laboratory of Bioreactor Engineering, School of Biotechnology, East China University of Science and Technology, Shanghai, China, weizhenhuapiao@163.com
authors.forename: Zhen-Hua
authors.initials: ZH
authors.lastname: Wei
authors.forename: Linquan
authors.initials: L
authors.lastname: Bai
authors.forename: Zixin
authors.initials: Z
authors.lastname: Deng
authors.forename: Jian-Jiang
authors.initials: JJ
authors.lastname: Zhong
mesh_terms: D001483:Base Sequence; D003470:Culture Media; D017931:DNA Primers; D005285:Fermentation; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D007294:Inositol / Q000031:analogs & derivatives* / Q000096:biosynthesis; D009584:Nitrogen / Q000032:analysis*; D060888:Real-Time Polymerase Chain Reaction; D013302:Streptomyces / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D003470:Culture Media; D017931:DNA Primers; C030790:validamycin A; D007294:Inositol; D005954:Glucosephosphate Dehydrogenase; D009584:Nitrogen