Study On The Mutagenesis Of Ganoderma Lucidum And Liquid Fermention Of New Strain In Rice Bran And Wheat Bran Media

Ganoderma lucidum is a medicinal and edible large fungus with various active components and pharmacological effects,which has been widely used in food,medicine and cosmetics.Rice bran and wheat bran have a wide range of sources but low utilization,as primary by-products of agricultural products in China.It's essential to develop a high-value and high-efficiency utilization of rice bran and wheat bran.In this study,Ganoderma lucidum strain was improved to obtain a preponderant new strain with mutagenesis.The liquid fermentation of Ganoderma lucidum mutant was applied to produce bioactive Ganoderma lucidum mycelia and polysaccharides with bio-converted rice bran and wheat bran.It provided a solution of high-value using rice bran and wheat bran,and high-yield producing Ganoderma lucidum raw materials.The main contents and results of this study are as follows:?The Ganoderma lucidum JSU LIU1 was subjected to UV mutagenesis to obtain a mutant strain Ganoderma lucidum JSU LIUYU18 with higher growth rate and fermentation performance.After the liquid fermentation of Ganoderma lucidum mutant,the dry weight of mycelia was 2.321 g/100mL,the content of mycelial polysaccharides was 124.169mg/100mL,the content of exopolysaccharides was 410.029 mg/100mL,and the dry weight of residue was 0.715 g/100mL.The yields respectively improved 16.1%,15.5%,18.0%,and the utilization of substrates increased 7.6%,compared to the original strain.Ganoderma lucidum JSU LIUYU18 was identified as a new strain by antagonistic test and ITS gene sequence analysis.?The Ganoderma lucidum JSU LIUYU18 liquid fermentation medium was optimized.With designed single factor and U₁₁?11³?uniform experiments about the components of Ganoderma lucidum JSU LIUYU18 liquid fermentation medium,the optimized medium was obtained that every 100 mL of medium contained 1 g rice bran,9 g wheat bran and 0.25 g magnesium sulfate heptahydrate.After fermentation,the dry weight of mycelium was 4.261 g,the content of mycelial polysaccharides was 450.127 mg,the content of exopolysaccharides was 1141.416 mg,and the dry weight of residue was 1.362g.?The mycelial growth kinetic model of Ganoderma lucidum JSU LIUYU18 was constructed.U₂₄?24⁴?uniform experiment about components of the fermentation medium and time,was carried out to obtain the mycelial growth empirical kinetic model of Ganoderma lucidum JSU LIUYU18 by SPSS regression.According to the model equation,the mycelial dry weight was predicted under different fermentation conditions.The SPSS nonlinear regression and U₁₆?16³?uniform experiment were used to obtain the expressions of?_m and C_x,max which were the parameters of logistic model equation.The mycelial growth theoretical kinetic model of Ganoderma lucidum JSU LIUYU18 was come out,eventually.?The safety of Ganoderma lucidum mycelia and antioxidant activity of Ganoderma lucidum polysaccharides were determined.The content of contaminants in the Ganoderma lucidum mycelia was measured.The content of plumbum was 0.365 mg/kg,the content of cadmium was 0.0698 mg/kg,the content of mercury was 0.0122 mg/kg,the content of arsenic was 0.438 mg/kg,the content of copper was 6.55 mg/kg,the content of chromium was 21.8 mg/kg,there were not aflatoxin and pesticide residues.The Ganoderma lucidum polysaccharides,isolated and purified from the mycelia of Ganoderma lucidum,was qualitatively analyzed to be crude polysaccharides without starch,amino acid and peptide by iodine-potassium iodide reaction,ninhydrin reaction and Molish reaction.The DPPH·,·OH and O₂·?clearance and total reducing power of Ganoderma lucidum polysaccharides were measured.And the results show that the polysaccharides has certain antioxidant activity in vitro.