| Ganoderma lucidum is a traditional medicinal and edible fungus in China with anti-tumor,anti-inflammatory,anti-bacterial and anti-aging effects.At present,there are three main culture methods of Ganoderma lucidum,which are fruiting bodies cultivation,liquid culture and solid-state culture.Compared with the first two culture methods,there are fewer studies related to the solid-state fermentation of Ganoderma lucidum,and currently most of the media containing some chemical components are used,which is not conducive to the later application of the fungal mass.In this thesis,a natural medium with wheat bran as the main ingredient was selected for solid-state culture of Ganoderma lucidum,and the response surface optimization of the mycoplasmic fermentation process was carried out based on three indicators: biomass,polysaccharides and triterpenes.In addition,the transcription levels of the relevant enzyme genes in the active product synthesis pathway and the antioxidant properties of Ganoderma lucidum mycoplasm were also investigated.The results are as follows:(1)Selection of solid medium:Using wheat bran as main material,corn flour and indica rice flour as carbon source,peanut flour and soybean flour as nitrogen source,nine kinds of solid-state culture media were combined.Taking biomass as the index,under the culture conditions of temperature30 ℃,initial water content 60%,inoculation amount 10%,stirring interval 120 h and culture days 10 days,the selection and optimization of solid-state medium were carried out.The optimal solid-state medium was wheat bran + corn flour + soybean flour,and the mass ratio was 2:1:1.Then the mycelial biomass in the mycelium under the medium was199.04 ± 9.58 mg / g.(2)Response surface optimization of three fungal substance processes:Taking mycelial biomass,mycelial polysaccharide and mycelial triterpene as indicators,the culture conditions of Ganoderma lucidum mycelium were optimized by response surface analysis.The results of the optimal process parameters are as follows:The optimum technological parameters of mycelial biomass were as follows: the initial water content was 66%,the culture temperature was 26.5 ℃,and the inoculation amount was 10.7%.On the basis of this condition,after 120 h stirring interval and 10 d culture time,the mycelial biomass was as high as 0.2598 g / g.The optimum technological parameters of fungal substance polysaccharide after response surface analysis were as follows: the initial water content was 60%,the culture temperature was 29 ℃,and the inoculation amount was 9.7%.On the basis of this condition,after 120 h stirring and 10 d culture time,the maximum value of fungal substance polysaccharide can be as high as 328.241 mg / g.The optimum technological parameters of fungal substance triterpenoids after response surface analysis optimization method are as follows: initial water content 60%,culture temperature 30 ℃,inoculation amount 7.6%.After 47 h stirring interval and 8 d culture time,fungal substance triterpenoids can be obtained up to 35.717 mg / g.(3)Selection and comparison of three fungal substance processes:Under the polysaccharide process,the relative expression of PGM,UGP and GLS genes reached the maximum on the 6th day.The relative expression of PGM gene was1.53 and 1.36 times higher than that of biomass and triterpene process;The relative expression of UGP gene was 2.13 and 1.85 times higher than that of biomass and triterpene technology;The relative expression of GLS gene was 1.83 and 1.31 times higher than that of biomass and triterpene technology.In the triterpene process,the relative expression of HMGR and SQS genes reached the peak on the 8th day,and the relative expression of LS and Se genes reached the maximum on the 6th day.The relative expression of HMGR in triterpene process was 1.12 and 1.66 times higher than that in biomass and polysaccharide process,respectively.When the relative expression of SQS gene reached the peak,it was 1.6 and 1.98 times higher than that of biomass and polysaccharide technology,respectively.On the 6th day,the relative expression of LS in the three processes was similar.On the 8th and 10 th day,the expression of LS in triterpene process was higher than that in the other two processes.When the relative expression of Se gene reached the peak,it was 1.87 and 1.35 times higher than that of biomass and polysaccharide technology,respectively.The active components in the three kinds of mycelial processes were compared.When cultured for 10 days,the mycelial biomass in the biomass process was 1.51 and1.83 times higher than that in the polysaccharide and triterpene processes,respectively;The content of fungal substance polysaccharide in polysaccharide process was 1.49 and1.28 times higher than that in biomass and triterpene process,respectively.When cultured for 8 days,the content of fungal substance triterpene in triterpene process was 1.25 and1.26 times higher than that in biomass and polysaccharide process,respectively.In the three processes,if there is a certain demand for mycelial biomass,fungal substance polysaccharide and fungal substance triterpene,the fungal substance polysaccharide process with relatively balanced content is selected for culture.(4)Antioxidant properties of three fungal substance:The total reducing capacity,DPPH radical scavenging capacity and hydroxyl radical scavenging capacity of the three bacteria were measured.Based on the above three indexes,it was found that the antioxidant characteristics of biomass process were the strongest on the 8th day The antioxidant properties of polysaccharide process were the strongest on the 8th day The antioxidant properties of triterpene process were the strongest on the 10 th day.In this paper,three fungal substance quality processes are optimized for different active components of Ganoderma lucidum.On the premise of ensuring the content of active components in Ganoderma lucidum,we can try to food Ganoderma lucidum in the future. |
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