Study On The Optimization Of Production Technical Parameters Of Pleurotus Eryngii Liquid Spawn And The Change Of Mycelial Activity

Liquid spawn,an important technical support for industrial production of edible fungi,has some advantages,such as fast growth,strong activity,uniform quality and easy inoculation.However,the study of the fermentation parameters of Pleurotus eryngii liquid spawn is less,and the research on the change of mycelial activity of liquid spawn is unclear,which can not effectively guide the production practice.Therefore,in order to provide a theoretical basis for the production of liquid spawn and industrial production of Pleurotus eryngii,response surface analysis was used to optimize the liquid spawn formula and conditions,and through adding different substances to the medium to explore the changes of mycelial activity,The main results are as follows:（1）The best carbon and nitrogen source of liquid medium was glucose and yeast extract,respectively.The optimum formula of medium was obtained by response surface analysis.Combined with the practical operation,the formula was modified to 29.00 g/L glucose,2.90 g/L yeast extract,0.90 g/L KH₂PO₄ and 1.00 g/L Mg SO₄.The effects of various factors on the dry weight of mycelia was analyzed,the results indicated that the influence follow the sequence:glucose,KH₂PO₄,yeast extract and Mg SO₄,among them,the first two factors had significant effect.The interaction between glucose and KH₂PO₄ had obviously effect on the dry weight of mycelia.The interaction between glucose and yeast extract had a certain effect.（2）The optimum culture conditions of liquid spawn were obtained by response surface analysis.Combined with the actual situation,the conditions were modified to liquid volume 106.00 m L/250m L,rotating speed 165.00 r/min,temperature 23.60℃,initial p H 6.70.The effects of various factors on the dry weight of mycelia was analyzed,the results indicated that the influence follow the sequence:initial p H,liquid volume,temperature and rotating speed,among them,the first three factors had extremely significant effect.The interaction of liquid volume and rotating speed,temperature and initial p H had obviously effect on mycelial dry weight.（3）The effect of additives on mycelial activity was studied.Along with the increase of culture time,superoxide anion production rate,H₂O₂ concentration,relative conductivity,MDA,soluble protein and soluble polysaccharide content increased,while hydroxyl radical scavenging rate,CAT,POD,APX and SOD activities,soluble sugar,soluble amino acid and proline content decreased.VB₁（promoting mycelial activity）and Na Cl（inhibiting mycelial activity）were selected as additives.These two additives had significant effects on superoxide anion production rate,H₂O₂ concentration,hydroxyl radical scavenging rate,soluble amino acid content,POD,APX and dehydrogenase activity,and had significant effects on relative conductivity,MDA and soluble polysaccharide content in the middle and late stage of culture.In addition,the activities of SOD were only significantly affected by Na Cl,and the content of proline was only significantly affected by VB₁.（4）The result of spearman correlation analysis shows that the culture time was significantly positively correlated with superoxide anion production rate,H₂O₂ concentration,relative conductivity,MDA and soluble protein content.The hydroxyl radical scavenging rate,CAT,POD,APX and SOD activities,soluble sugar and soluble amino acid content and dehydrogenase activity were significantly negatively correlated with culture time and positively correlated with growth rate.The growth rate was negatively correlated with H₂O₂ concentration.Combined with the above data,it was inferred that H₂O₂ concentration,hydroxyl radical scavenging rate,soluble amino acid content,POD,APX,SOD and dehydrogenase activities are the important evaluation indicators of the effects of additives on mycelial activity.（5）The result of path analysis showed that SOD activity was most closely related to mycelial dry weight,and hydroxyl radical scavenging rate was most closely related to mycelial growth rate.The physicochemical parameters interact with each other,and all the physicochemical parameters had synergistic effects on mycelial dry weight and growth rate.