After successfully defending his dissertation entitled "Lichens of the Dnieper Upland" (1985), Kondratyuk continued to work at the institute, having passed the path from junior to leading researcher, head of the laboratory and department, scientific secretary, deputy director and finally acting director of the institute.
In 1996 Kondratyuk defended his doctoral dissertation "Lichen flora of the plains of Ukraine and its analysis"; in 2006 he received the title of Professor.
[2] Since 1995, Kondratyuk has been working for many years with Professor Ingvar Kärnefelt from the Botanical Museum of Lund University (Sweden) to study lichens of the family Teloschistaceae.
Extensive collaborations with South Korean scientists have also resulted in the description of many taxa previously unknown to science.
Issue 9" (2004), "Lichen-Forming, Lichenicolous and Allied Fungi of Israel"(2005), "Lichenoindication (Manual)" (2006), "Indication of the state of the environment of Ukraine with the help of lichens" (2008).