Preparation Of Gold Nanomaterials And Their Effects On Fermentation Of Active Products Of Ganoderma Lingzhi

Nano materials are ultrafine particles with a size of 1～100 nm.Their properties are significantly different from those of conventional materials because of their small size effect,surface effect,quantum size effect and macro quantum tunneling effect.As the most mature nano materials,gold nano materials have the advantages of good biocompatibility,low cost and stable properties.As the most mature nano materials,gold nano materials have the advantages of good biocompatibility,low cost and stable properties.They are often used in biomedical fields,such as biosensor,medical diagnosis and biological imaging.There are few studies on the effects of exogenous substances such as nano materials on the synthesis of fungal metabolites.In this paper,three different forms of gold nanomaterials,gold nanoparticles(AuNPs),gold nanorods(AuNRs)and gold nanoclusters(AuNCs),were selected as the research materials to investigate their interaction with Ganoderma lingzhi(G.lingzhi.)mycelial cells and their effects on the synthesis of liquid fermentation of important active products in G.lingzhi.The main research results are as follows:1.Synthesis of three different gold nanomaterialsAuNPs,AuNRs and AuNCs with representative size and three-dimensional shape were selected as the representatives of gold nanomaterials.Firstly,AuNPs(30 nm)were prepared by sodium citrate reduction method.They showed wine red in sunlight,and there is an obvious absorption peak at 520 nm.Secondly,AuNRs were prepared by seed crystal method.The length and width of the synthesized AuNRs were 30 nm and 10 nm.The AuNRs showed black brown under sunlight,and the UV absorption diagram had two peaks at 512 nm and 820 nm.The centrifugal purification results showed that the blue shift of UV absorption spectrum by 4 nm indicated that the impurities in AuNRs had been removed.Finally,AuNCs(2～5 nm)were synthesized by template method.It was golden yellow in sunlight and had an obvious absorption peak at 360 nm;AuNCs showed orange fluorescence under ultraviolet light.When the excitation wavelength was 404 nm,the fluorescence spectrum had a peak at 600 nm.The results of dialysis purification showed that the peak value of fluorescence spectrum increased,which realized the purification of AuNCs.2.Interaction of three gold nanomaterials with G.lingzhi mycelial cellsThe effect of three gold nanomaterials on the growth of G.lingzhi was studied by taking the biomass of mycelium and the transformation of the cells to carbon sources as the indicators.The results showed that all three gold nanomaterials could inhibit the biomass of G.lingzhi hyphae.The measurement results of amylase showed that the enzymatic activity of the gold nanomaterials group was affected,and the peak of enzymatic activity was delayed from the 3rd day to the 5th day.The results of fluorescence microscopy showed that under the DAPI channel,the autofluorescence of Ganoderma lucidum hyphae was stronger,and compared with the control group,the hyphae morphology of the three gold nanomaterials did not change significantly after incubation.Electron microscopy results indicated that the larger AuNPs and AuNRs would be adsorbed on the surface of G.lingzhi mycelial cells,thereby affecting the surface morphology of the hyphae.3.Effects of three gold nano materials on the fermentation of main active products of G.lingzhiThe effects of different forms,different concentrations and different addition periods of gold nanomaterials on the production of polysaccharides and triterpenes by liquid fermentation of G.lingzhi were discussed.The results showed that the total polysaccharide content of G.lingzhi reached the maximum(333.83 mg/g)in the stable fermentation period and the concentration of AuNPs was 136 mg/L,which was increased by 50.37%compared with the control group(165.68 mg/g).The content of triterpenes reached the maximum(23.33 mg/g)in the stable fermentation period and the concentration of AuNRs was 136 mg/L,which was increased by 42.78%compared with the control group(13.35 mg/g).In this study,three kinds of gold nanomaterials with different forms were successfully synthesized,and the interaction between them and G.lingzhi mycelium cells was explored.For the first time,gold nanomaterials were used as exogenous materials to study their effects on the production of polysaccharides and triterpenes by liquid fermentation of G.lingzhi.This study provides a reference for the application of nanomaterials in the field of medicinal fungi fermentation.