Biotransformation of citronellal, geranial, citral and their analogs by fungus and their antimicrobial activity

Biotransformations of citronellal and geranial were carried out using Botrytis cinerea as a biocatalyst. Biotransformation of citronellal using B. cinerea produced 100% citronellol on the third day. Conversely, no reaction was observed when citronellol was added to culture containing B. cinerea. Biotransformation of geranial using B. cinerea produced almost 100% geraniol after 18 h. Biotransformation of citral (mixture of neral and geranial) using B. cinerea produced almost 100% citrol (nerol and geraniol) on the third day. Examination of the antimicrobial activity of the related compounds revealed that citronellal and citronellol showed activity against Escherichia coli (ATCC 25922), methicillin-resistant Staphylococcus aureus (MRSA) and Candida albicans but showed no activity against enterohemorrhagic Escherichia coli (EHEC) or Pseudomonas aeruginosa. The same findings were obtained using the sensitive disc method: citronellal and citronellol showed activity against Escherichia coli (ATCC 25922), MRSA and Candida albicans but not EHEC or Pseudomonas aeruginosa.