Background: Validamycin A (Val-A) is one of the most widely used agricultural antibiotics
in East Asia especially for controlling rice sheath blight disease. Fermentation contamination of the
industrial Val-A producing strain is a common occurrence.
Methods: Fermentation culture of S. hygroscopicus 5008 has a special smell that could be distinguished
from other tainted samples. The change of the volatiles in untainted and tainted samples was
characterized using headspace solid phase microextraction (HS-SPME) combined with gas chromatography-
mass spectrometry (GC-MS).
Results: Seventy-one volatile compounds (including alkanes, amines, alcohols, esters, aldehydes and
others) were identified and there were significant differences in the composition of volatiles among
different samples. Principal component analysis (PCA) based on the GC-MS data was used to identify
the important volatile compounds that contributed to the differentiation of the fermentation samples
under different fermentation stages, as well as among different pollution species and fermentation media.
Contamination could be discovered in time irrespective of the stage of fermentation and the contaminating
bacteria in broth.
Conclusion: It is the first report to detect contamination by volatile compounds in the antibiotic fermentation
and it was proved that HS-SPME/GC-MS is an effective contamination detection method in