menaquinone-7 and n-hexane

The effect of milking menaquinone-7 (MK-7) with biocompatible organic solvents on MK-7 production in B. subtilis fermentation was studied. Periodic milking of MK-7 from the fermentation medium by n-hexane significantly enhanced the total MK-7 production ~ 1.7 fold at the end of 72 hours of fermentation (p < 0.05) as compared to the control medium.. Milking of MK-7 with a mixture of n-hexane phase modified with n-butanol was also explored. Although milking of MK-7 by a mixture of n-hexane and n-butanol (1:2, v/v), was found to be appropriate in terms of high extraction capacity, no significant increase in total MK-7 concentration was observed. Biocompatibility between the extraction solvents and B. subtilis was also examined.. The results indicated that the mixture of n-hexane and n-butanol exhibited some detrimental effects. However, n-hexane alone exhibited delayed toxicity starting at 84 hours of periodic milking and could, therefore, be considered as the most promising organic solvent for milking MK-7 in B. subtilis fermentation while enhancing the productivity of the system.

Topics: 1-Butanol; Bacillus subtilis; Fermentation; Hexanes; Solvents; Vitamin K 2

An efficient and accurate HPLC method was developed for the determination of menaquinone-7 (MK-7) in microbial fermentation using 2-propanol and n-hexane as extraction solvents as well as the eluent.. Extraction was carried out with 2-propanol and n-hexane (2:1, v/v) after enzymatic hydrolysis with 1% (w/v) lipase and ethanol water treatment prior to quantification in order to remove interfering lipids and denatured proteins. Chromatographic separation of MK-7 was accomplished isocratically on a C 18 Gemini column using a mobile phase mixture of 2- propanol: n-hexane (2:1, v/v) with a flow rate of 0.5 mL/min. UV detection was carried out from 200-400 nm and the chromatogram was extracted at a wavelength of 248 nm. A linear response was shown by the method with a coefficient of determination (R2) value of 0.9982.. The recoveries of MK-7 were greater than 94% and the intra and inter day R.S.D values were less than 2%, demonstrating the accuracy of the method. The lower limit of detection (LOD) and the limit of quantification (LOQ) were 0.1 µg/mL and 0.29 µg/mL, respectively.. The general usefulness of the described method is demonstrated by the application of this method in the analysis of MK-7 from Bacillus species. Under these conditions, the analysis of MK-7 was achieved in less than 8 minutes with a retention time of 7.19 ± 0.1 minutes.

Topics: Bacillus subtilis; Chromatography, High Pressure Liquid; Chromatography, Reverse-Phase; Dose-Response Relationship, Drug; Hemostatics; Hexanes; Humans; Reproducibility of Results; Vitamin K 2