Effects Of Different Culture Materials On Biotransformation Of Ganoderma Lucidum And Its Mechanism

Ganoderma lucidum is a valuable medicinal fungus which has an abundance of bioactive components,with the functions of immunomodulation,antitumor,antioxidation and hepatoprotection.Sawdust has been used as primary materials to cultivate Ganoderma lucidum.In order to reduce the cost of raw materials and slow down the contradiction between edible fungi and forests during the cultivation of Ganoderma lucidum,the feasibility of cultivating Ganoderma lucidum with P.purpureum cv.Jujuncao and its biogas residues was studied in this paper.Firstly,in this study,biogas residues of P.purpureum cv.Jujuncao were used as primary materials to cultivate Ganoderma lucidum.Within the five Ganoderma lucidum strains,Hanzhi was proved to be the most suitable species growing on biogas residues.In this kind of culture materials,the mycelium of Hanzhi was white,strong,and grew well.Secondly,the influence of five different substrates on mycelial growth,yields,nutrient components and heavy metal content of Ganoderma lucidum were analyzed.To obtain a comprehensive assessment of the five different substrates,the rates of mycelial growth,yields,polysaccharides,and triterpenoids were analyzed by grey relational degree method.The results showed that both formula 1(biogas residue 41%,sawdust 40%,wheat bran 15%,corn flour 3%,and gypsum powder 1%)and formula 3(P.purpureum cv.Jujuncao 76%,wheat bran 20%,corn flour 3%,and gypsum powder 1%)could increase economic benefits.Thirdly,the effects of five different substrates on extracellular enzyme(laccase,MnP,CMCase and hemicellulase)activities of Ganoderma lucidum mycelium at four different growth stages(20 days,full bag,the original base period,mature period)were analyzed.The results showed that the extracellular enzyme,such as laccase,MnP,CMCase and hemicellulase,showed a dynamic change during the growth and development of Hanzhi,and the different culture substrates significantly affected the activity of these extracellular enzymes.Fourthly,the nutritional components,such as crude protein,crude fat,crude fiber,crude ash and amino acid,which were from four different mushroom culture medium and their spent mushroom substrate were measured.The results showed that after the transformation of Hanzhi,the contents of crude protein,amino acid and crude ash of these four different culture materials were improved,among which sawdust and biogas residue formula was the most prominent.While the content of crude fat and crude fiber decreased significantly and the sawdust and biogas residue were the most significant.Base on RNA-Seq analysis,differentially expressed genes(DEGs)between MZ-20 and S-20,MZ-Y and S-Y,MZ-F and S-F were screened.The results showed that there were 2538 DEGs between MZ-20 and S-20,by the gene expression analysis,including 1367 up-regulated genes and 1171 down-regulated genes.There were 3605 DEGs between MZ-Y and S-Y,by the gene expression analysis,including 1646 up-regulated genes and 1959 down-regulated genes.There were 1064 DEGs between MZ-F and S-F,by the gene expression analysis,including 618 up-regulated genes and 446 down-regulated genes.DEGs associated with extracellular enzymes between MZ-20 and S-20,MZ-Y and S-Y were screened,and DEGs associated with triterpenoid synthetic pathways between MZ-F and S-F were analyzed.The expression of the gene encoding laccase in MZ-20 were lower than in S-20.The expression of the gene encoding endoglucanase,laccase and endo-1,4-beta-xylanase in MZ-Y were higher than in S-Y.Compared with S-F,the genes encoding farnesyl-diphosphate synthase(FPPS)and 3-hydroxy-3-methylglutaryl-coenzyme A reductase(HMGR)were up-regulated in terpenoid synthesis pathway of MZ-F.