Dissertation
Dissertation > Agricultural Sciences > Crop > Economic crops > Medicinal crops > Thermophilic drugs > Licorice

Separation and Fermentation Cultivation of Endophytic Fungi Producing Glycyrrhizic Acid from Ordos Plateau Licorice

Author WangHongXia
Tutor LiYaLi
School Inner Mongolia University of Science and Technology
Course Genetics
Keywords Liquorice Glycyrrhizic acid Endophytic fungi Fermentation cultivation
CLC S567.71
Type Master's thesis
Year 2011
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Endophytic fungi is a widespread microbes special groups but has not been fully knownreferring to those fungi which living in healthy plant body not cause any disease symptom. Theygrow mainly in the plant root, stem, leaves such as plant tissues and form a relatively stable fungalcolonization. The endophytic fungi of medicinal plants have rich diversity and can produce the sameactive ingredient with host that have important application value in medicine, agriculture, industryand other industries. It has been became a hotspot in the research of the medicine drug by usingendophytic fungi fermentation to produce bioactive substances for industrial production, increasingyield and reducing the cost. In this study,37strains endophytic fungi were separated and purifiedfrom the root of ordos plateau licorice and four strains produced glycyrrhizic acid were identified byHPLC, LC-MS, meanwhile the fermentation culture conditions of strains B12were optimized.Experimental results summed up as follows:(1) The surface disinfection of licorice root method that more ideal choice was tested: rinsed with75%ethanol for30s at first, sterile water to rinse4times, then rinsed with3%H202for3min,sterile water rushed washing four times, each time5min. an last rinsed with0.1%HgCl for1minand water to rinse4times and reaching both thoroughly kill the surface epiphytes, at the sametime, not miscellaneous bacteria affect internal fungi separation requirements.(2)37strains licorice endophytic fungi were separated by preliminary identification, these strainsbelong to two orders, three families, six genera, they respectively belong to Fusarium,Penicillium, Aspergillus, Alternaria, trichoderma, richoderma. It can be explained thatrhizosphere microorganisms may be the main source of most endophytic fungi.(3) The four endophytic fungi.produced glycyrrhizic acid were separation by HPLC screening:fungal B6, B12, B23B17, by LC-MS further appraisal, strains of B12can produce virtuallyglycyrrhizic acid, its production was346.1μg/L, compared with other reported strains, theglycyrrhizic acid production of fungi B12was high yield. Strains B12was identifiedpreliminarily the strains of mold spores for sickle. after analysis of its morphological properties.(4) With accumulated dry weight of mycelia for the index, by selecting the basic medium type,cultivate concentration of carbon source types, nitrogen source types, pH value, wave bed speed,the incubation temperature parameters, best foundation for cultivating conditions were by theproduction glycyrrhizic acid. The results showed that the most optimized culture conditions ofendophytic fungi B12was: potatoes sucrose medium, liquid medium carbon sources, nitrogen source for glucose for specially designed, best initial pH value for the7.0,4%fermentation, theoptimum temperature for28℃, rotate speed150rpm, in these culture conditions mycelia dryweight reach a maximum for8.7g/L.

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