The ability of microfungi to destruct organic compounds can be the object of envy for any processing plant. However, they sometimes destroy things that people prefer to keep safe – for example, paints of the masterpieces. The good news is that some of their biochemical reactions can be used in pharmacy. The scientists of Federal Research Centre «Fundamentals of Biotechnology» of the Russian Academy of Sciences managed to find such fungi and wrote about their success in scientific magazine Biology.
Steroids are a large group of medicine that is used from the middle of the 20th century. They can possess antiphlogogenic and analgetic effect, substitute hormones and quicken metabolism. Originally, they were produced with the help of multistage chemosynthesis. But in the course of time people found out that due to the abilities of microorganisms it is possible to synthesize necessary substances using less stages. The ability to transform steroids which are important for pharmacy was found in various groups of microorganisms. On the base of these researches scientists got improved strains of microorganisms for high-potency transformations of various steroids. The scientists of Federal Research Centre «Fundamentals of Biotechnology» of the Russian Academy of Sciences found out that fungi, that destroy tempera, also can be used in pharmacy.
“In tempera people use yolk as binding component and in dry state it contains up to 2 % of cholesterol, and varnishes contain numerous triterpenoids. All these compounds have common biosynthesis pathways with steroids, widely used in pharmacy. Nowadays people use more than 300 steroids in the pharmaceutical industry. The annual world output of steroids is more than 10 milliards dollars and ranks second place in pharmaceutical market after antibiotics” – states Alexander Zhgun, the leader of Group of fungal genetic engineering of Federal Research Centre «Fundamentals of Biotechnology» of the Russian Academy of Sciences and the lead author of this research.
During previous researches scientists took more than 100 microbiological samples from tempera paintings in the Main Building of State Tretyakov gallery and isolated from them 10 strains of hyphomycetes (filamentous fungi), which can destroy paintwork materials. Biotechnologists described the structure of these fungi and chose new effective antiseptics, that enable to protect paintings from destruction.
Cultivation of fungi-destructors of tempera paintings, isolated in the State Tretyakov Gallery (STG, Moscow, Russia) on Czapek-Dox agar (CDA) medium, 25 °C, 15 days. (a) Slant CDA medium; (b) CDA medium on Petri dishes. Fungal strains, from left to right: STG-25G, STG-52B, STG-57, STG-96, STG-86, STG-93B, STG-36, STG-103, STG-93W, STG-106.
In current study the researchers studied the characteristics of these hyphomycetes in more detail. Biotechnologies were interested in their ability to convert androstenedione, endogenous weak androgen steroid hormone and intermediate in the biosynthesis of estrone and of testosterone in liquid media and binding buffer. In total the scientists managed to synthesize 33 species of steroids with the help of fungi, provided that structure of 19 compounds was found due to gas chromatography and mass-spectrometry. Some strains coped with this task almost as well as the industrial strain Curvularia lunata RNCIM F-981.
«In many cases the advantages of biotransformation of steroids are caused by single-step regio -and/or stereospecific reactions, catalyzed by special enzymes and not always accessible for chemical synthesis. The steroid’s nuclear structure is also sensible to splitting by numerous chemical substances, and the use of biotransformation can sometimes solve the specific problem of synthesis. Moreover, biotransformation of steroids is more ecological than multiple studies of chemical synthesis. For the first time we proved that fungi, destroyers of tempera, possess steroid-transforming capacity and can be treated as advanced microorganisms for screening of biotechnologically-important transformations of steroids and their future industrial use», – summarized Alexander Zhgun.