A novel, simple and highly sensitive method was developed for the rapid analysis of phenolic antioxidants at trace level in edible oils. It was based on dispersive liquid-liquid microextraction ( DLLME ) and gas chromatography-mass/mass spectrometry ( GC-MS/MS) . Related important factors that may influence enrichment efficiency, such as type and volume of extraction solvent, type and volume of dispersive solvent, and extraction time were investigated and optimized in detail. The optimum conditions were as follows:a quick injection of 500 μL mixed solution ( methanol:acetonitrile=1:1 , V/V ) into 1 . 0 g oil sample with 3 mL n-hexane for 10 s of extraction time. Under the optimal conditions, the linearity (10-2000 ng/g), limits of detection (1. 5-2. 4 ng/g) and relative standard deviations (4. 0%-8. 3%) was obtained. The proposed method was applied for the analysis of 4 edible oil samples. Some of phenolic antioxidants were detected in three of them, and the recoveries of spiked samples were in the range of 81. 9%-118%.

Tacrolimus (FK506) is a 23-membered macrolide with immunosuppressant activity that is widely used clinically for treating the rejection after organ transplantation. The research on tacrolimus production was mainly focused on biosynthesis methods, within which there are still some bottlenecks. This review summarizes the progress made in tacrolimus biosynthesis via modification of metabolic pathways and control of fermentation process, with the hope to address the technical bottlenecks for tacrolimus biosynthesis and improve tacrolimus production by fermentation engineering and metabolic engineering.
Tacrolimus ; Immunosuppressive Agents ; Fermentation ; Macrolides ; Anti-Bacterial Agents