The soluble microbial products (SMPs) in the fermentation solution
were analyzed by another GC using flame ionization detector
(FID). A 2-m stainless steel column was packed with the supporter
GDX-103 (60–80 meshes). The temperatures of the injection port,
oven and detector were 220, 190 and 220 C, respectively. The
carrier gas was nitrogen at a flow rate of 30 ml/min.