2.7 High performance liquid chromatography(HPLC)an...
Strains were cultured as described above，and three replicates of culture media with only extracts of H.serrata were also prepared.The cultured media after filtration were concentrated on a rotary evaporator and then extracted twice with chloroform.The combined chloroform extracts were evaporated to dryness.The dry residues were dissolved with 2mL methanol and filtered through 0.22μm polytetrafluoroethylene syringe filters before HPLC analysis.A C18 column(Agilent Eclipse plus-C18，5μm，4.6mm×250mm，Agilent Technologies，Santa Clara，CA，USA)was used for separation at 30℃.The mobile phases consisted of ammonium acetate(15mmol/L)and methanol(70：30，vol/vol，p H 6.0)at a flow rate of 1mL/min.Detection of Hup A was performed at a wavelength of 308nm.Hup A produced by the mutant was calculated as the total Hup A content in the mutant fermentation broth minus Hup A content of the broth with only extract of H.serrata.(https://www.daowen.com)