2.5. Analytical methods
Glucose concentration was analyzed by an enzymatic bio-analyzer
(SBA-40C, Shandong Academy of Sciences, China). Rapeseed oil
concentration in the broth was quickly determined by the low-field
nuclear magnetic method. [19] For biomass
determination, three parallel broth samples were washed twice with
alcohol and dried at 80℃ for 24 h to measure
dry cell weight (DCW). The
concentrations and structures of SLs were determined by HPLC and
HPLC-MS, respectively. [7]