Abstract: The cell free filtrate of Flammulina velutipes (FV-CFF) obtained by two-stage fermentation was used for the synthesis of silver nanoparticles (AgNPs) and their effects were studied. The results showed that FV-CFF acted on AgNO3 to produce stable brown AgNPs solution, and AgNPs production was increased with pH elevation. The reducing power of FV-CFF on AgNO3 was significantly inhibited at pH<5, but exhibited a linear growth trend within the pH range of 5-11. The kinetic curve of AgNPs synthesis was acquired by determining AgNPs generation using FV-CFF at normal pH (7.22) and pH 11, respectively. The effect of freezing and thawing was also compared by calculating the formation kinetic curve. The apparent activation energy (Ea) obtained was 98.96 kJ/mol (pH 7.22, initial), 106.725 kJ/mol (pH 7.22, thawed), 119.82 kJ/mol (pH 11, initial), 80.21 kJ/mol (pH 11, thawed), respectively. The results of composition and reducing power determination showed that although freeze-thaw could remove a mass of proteins and carbohydrates in FV-CFF, it had a relatively low effect on reducing power. However, the increasing pH could significantly improve the reducing power of FV-CFF, and the maximum absorption wavelength and particle size of synthesized AgNPs were also significantly reduced at pH 11. The present results will be contributed to further analysis of AgNPs synthesis mechanism by F. velutipes.
[1] SINGH D K, KUMAR J, SHARMA V K, et al.Mycosynthesis of bactericidal silver and polymorphic gold nanoparticles:Physicochemical variation effects and mechanism[J].Nanomedicine, 2018, 13(2):191-207. [2] ESKANDARI-NOJEDEHI M, JAFARIZADEH-MALMIRI H, RAHBAR-SHAHROUZI J.Hydrothermal green synthesis of gold nanoparticles using mushroom (Agaricus bisporus) extract:Physico-chemical characteristics and antifungal activity studies[J].Green Processing and Synthesis, 2018, 7(1):38-47. [3] KUMAR S, LATHER V, PANDITA D.Green synthesis of therapeutic nanoparticles:An expanding horizon[J].Nanomedicine, 2015, 10(15):2 451-2 471. [4] OWAID M N, IBRAHEEM I J.Mycosynthesis of nanoparticles using edible and medicinal mushrooms[J].European Journal of Nanomedicine, 2017, 9(1):5-23. [5] FANG Y, ZHANG Y, WANG M, et al. In vitro bioaccessibility and speciation changes of selenium in Pleurotus eryngii during the growing stage[J].Food & Function, 2018, 9(8):4 493-4 499. [6] YEHIA R S, AL-SHEIKH H.Biosynthesis and characterization of silver nanoparticles produced by Pleurotus ostreatus and their anticandidal and anticancer activities[J].World Journal of Microbiology and Biotechnology, 2014, 30(11):2 797-2 803. [7] 董丽娜, 刘学瑞, 王慧杰, 等.秀珍菇菌丝体无细胞滤液的应用:银纳米颗粒的生物合成及其抗菌活性[J].辐射研究与辐射工艺学报, 2019, 37(5):43-50. DONG L, LIU X, WANG H, et al.Application of cell-free filtrate of Pleurotus geesteranus mycelium:Biosynthesis of silver nanoparticles and their antimicrobial activity[J].Journal of Radiation Research and Radiation Processing, 2019, 37(5):43-50. [8] BANERJEE K, RAVISHANKAR R V.A review on mycosynthesis, mechanism, and characterization of silver and gold nanoparticles[J].BioNanoScience, 2018, 8(1):17-31. [9] LIU Y, ZHANG B, IBRAHIM S A, et al.Purification, characterization and antioxidant activity of polysaccharides from Flammulina velutipes residue[J].Carbohydrate Polymers, 2016, 145:71-77. [10] NARAYANAN K B, PARK H H, HAN S S.Synthesis and characterization of biomatrixed-gold nanoparticles by the mushroom Flammulina velutipes and its heterogeneous catalytic potential[J].Chemosphere, 2015, 141:169-175. [11] WANG J, WANG B, ZHANG D, et al.Selenium uptake, tolerance and reduction in Flammulina velutipes supplied with selenite[J].Peer J, 2016, 4:e1993. [12] LIU C, CHEUNG P.Structure and immunomodulatory activity of microparticulate mushroom sclerotial beta-glucan prepared from Polyporus rhinocerus[J].Journal of Agricultural and Food Chemistry, 2019, 67(32):9 070-9 078. [13] SAMROT A V, ANGALENE J, ROSHINI S M, et al.Purification, characterization and utilization of polysaccharide of Araucaria heterophylla gum for the synthesis of curcumin loaded nanocarrier[J].International Journal of Biological Macromolecules, 2019, 140:393-400. [14] NYT 2637—2014, 水果和蔬菜可溶性固形物含量的测定 折射仪法[S].北京:中华人民共和国农业部, 2014. NYT 2637—2014, Refractometric Method for Determination of Total Soluble Solids in Fruits and Vegetables[S].Beijing:Ministry of Agriculture of the People's Republic of China, 2014. [15] 唐思颉, 涂传海, 胡文秀, 等.红茶菌发酵黄浆水的体外抗氧化活性[J].食品科学, 2019, 40(17):1-6. TANG S, TU C, HU W, et al.Antioxidant activity of fermented soy whey with kombucha consortium[J].Food Science, 2019, 40(17):1-6. [16] LIU B, ZHANG M, ZHOU C, et al.Synthesis of monodisperse, large scale and high solid content latexes of poly(n-butyl acrylate) by a one-step batch emulsion polymerization[J].Colloid and Polymer Science, 2013, 291(10):2 385-2 398.
2021, Vol. 47 
