Study On The Production And Regulation Of Cordyceps Militaris Pigment

Cordyceps militaris is a well-known edible and medicinal fungus that is a potential source of natural pigments.Pigment content is a key factor affecting the appearance and quality of C.militaris.Therefore,the production and regulation of pigment are significant for high-quality cultivation of Cordyceps militaris.The study of pigment structure,function and its synthetic pathways will provide experimental basis for the deep development of C.militaris.The results showed that different nitrogen sources and concentrations affected the colony morphology and pigment production,and the colony color are different on media with different nitrogen sources in C.militaris.Organic nitrogen sources are more suitable for growth and pigment production.Dense colony formed on the media when peptone and yeast extract as nitrogen sources,the production of conidia was significantly higher than other nitrogen source(P<0.01),and the upper of colony was orange-yellow.Under the conditions of blue light,the carotenoid content was 4093.75 ± 518.37 ?g/g which was the highest and it was 2809.38 ± 386.24 under white light when 1% peptone was added,indicating that blue light and 1% peptone were best conditions for carotenoid production in fruiting bodies of C.militaris.Different wavelengths of light have significant effects on pigment production.Under the condition of two-stage culture and fruiting bodies cultivation,the carotenoid content was blue >white >green >pink and red light,and blue light contributes to the growth and pigment accumulation of C.militaris.The white light and blue light intensity tests showed that when the intensity of white light exceeds735 lux,the fruiting bodies exibited white,to different degrees,in which appearence and pigment content were affected.It should be noted that the white light intensity should be controlled in cultivation.The blue light(detection range: 17.3-64.3 lux)promoted fruiting body growth and pigment production.The carotenoid content of the fruiting body was 3747.92 ± 178.13 ?g/g when the blue light intensity was 64.3 lux.Under two-stage culture,the oxygen carrier n-dodecane and n-hexadecane promoted the mycelia growth and pigment accumulation of C.militaris within the range of 1-4%.Hydrogen peroxide(10-60 m M)can promote the accumulation of pigment in mycelia,indicating oxidative stress caused by hydrogen peroxide and oxygen carrier can significantly promote the production of carotenoids.Pigment can be produced in the mycelia and spores of C.militaris,and were produced extracellularly.After degreasing with petroleum ether and extracting with methanol,a new water-soluble pigment from C.militaris was extracted which has good antioxidant activity,and the extraction rate reach to 29.46% that has good development prospects.The IC50 value of DPPH· radical scavenging rate was 1.616 ±0.005 mg/ml.The molecular mass of the compound obtained by LC-MS is 522,which is different with the pigment reported before.The mutant library of C.militaris was successfully constructed by random insertion of Agrobacterium-mediated transformation(ATMT),and 114 white mutants were screened.The UV tolerance of the conidia of white mutants was significantly lower than that of wild-type strains,which indicate that the pigments produced by C.militaris may protect itself from UV irradiation.This study provided experimental basis for the high-quality cultivation of pigment-rich fruiting bodies of C.militaris and confirmed the development potential of C.militaris pigments to healthy products.