Studies On Fermentation Conditions Optimization Of Producing Red Pigment And Mutagenesisi Of Antarctic Fungus Geomyces Sp.WNF-15A

With the development of society and the improvement of life,people pay more attention to the food safety and health function.So it is a hot spot to search some strains of high yield stable pigment.In our laboratory,we screened a fungi Geomyces sp.WNF-15 A from Antarctic soil which can producered pigment steadily.Compared with the common food pigment,the red pigmen produced by Geomyces sp.WNF-15 A has the characteristics of high stability and security.In this study,the fermentation conditions of Geomyces sp.WNF-15 A were be explored and optimized in shake flask,7L and 200 L tanks,meanwhile it was treated by UV mutagenesis,and the fermentation conditions were also explored.The results showed:(1)The growth of WNF-15 A strain on solid plate had an effect on its fermentation.It was the most suitable for producing liquid seed when WNF-15A strain grew for 4days on the solid plate.It was the most suitable for expanding culture in shake flask when the liquid seed was cultured for 3.5 days andinoculated by 10% size.On this basis,OD533 of fermentation liquid in shake flask could reach the highest value19.462,when WNF-15 A strain was cultured for 12 days with a speed of 110r/min.(2)In 7L fermentation tank,the maximum peak value of OD533 could reach15.264 when the fermentation rotate speed was 90r/min and the ventilatory capacity was 3LPM.During the late fermentation,the effect of only adding glucose or potato were not good,but very well with PDA nutrient and the OD533 value could be increased by 18.51%.According to this condition,WNF-15 A strain was cultured in200 L tank for 10 days and the OD533 value of fermentation liquid could reach 9.762,while we could obtained 1.16g/L of pigment powder with 112.3 of color value through purification and drying.(3)Through the UV mutagenesis of Antarctic fungus WNF-15 A,we obtained 6strains with strong ability of producing pigment.The results of single factor and orthogonal test of mutant strain Y-014 showed : The pH and sugar concentration hadgreat influence on the fermentation,but the inoculation rate and the rotate speed were less.The best optimum combination were pH5.5,sugar concentration 3%,inoculum size 9%,and speed 110r/min.Based on the results obtained,we believe that the red pigment produced by Antarctic fungus WNF-15 A must has high popularization and application value...