英语翻译

英语翻译
MK-7isproducedby fermentationwithBacillus species.Because
of the low concentration of MK-7 in fermentation processes,
research has been focused on genetic mutation to improve the
productivity of bacteria [3,14,15] with limited attention paid to
the effect of nutrients on improving the concentration [14].The
nutrients ina fermentationmedia (carbonandnitrogen) canhave
a significant impact on the concentration of MK-7.
Until recently the general practice was to determine the optimal conditions of media using one component at a time; however,this method does not describe the interactions among the
variables.Recently designof experiments (DOE)has beenused in
theoptimizationoffermentationmedia [16–18].Theobjectiveof
this studywas toinvestigatethe effectandoptimumcombination
of nutrients that can increase MK-7 production in batch fermentation.Factorial experimental design was used to screen and
determine the key nutrients that can have a significant impact
on MK-7 production.Central composite face design (CCF) was
then employed to achieve the optimum concentrations of significant variables selected through screening design on MK-7
production.Validation of fermentation was then conducted;
the substrate concentrations (i.e.amino acids and glycerol),pH
andbacterialgrowthwerealsomeasuredduringthe fermentation process.
mk-7是menaquinone-7