LEXANDER E. HRISTOV1, NELLY E. CHRISTOVA1*, LYUDMILA V. KABAIVANOVA1, LILYANA V. NACHEVA1, IVANKA B. STOINEVA2 and PETAR D. PETROV3 1Stephan Angeloff Institute of Microbiology, Bulgarian Academy of Sciences, Sofia, Bulgaria 2Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Sofia, Bulgaria 3Institute of Polymers, Bulgarian Academy of ...