Transglycosylation of terpenes in cultures of Acremonium sp. DSM 24697

GIAI R; MAZZAFERRO L; GONZALEZ A; WEIZ G; PROST E; MOLEJON MI; BRECCIA J

San Luis

Congreso; XIII Congreso Argentino de Microbiología General; 2018

The fungus Acremonium sp. DSM 24697 produces the enzymes α-rhamnosil-β-glucosidase I and α-rhamnosyl-β-glucosidase II. These enzymes catalyze the hydrolysis of diglycosylated flavonoids to the corresponding disaccharide and aglycone, which are presumably further metabolized by the fungus as carbon sources. Moreover, they are able to in vitro transfer rutinosyl residues from rutinosylated-flavonoids to various hydroxylated acceptors. We hypothesized that this (?side?) transglycosylation activity also plays a role for the survival of the fungus, like the neutralization of toxic compounds through glycosylation. Since many terpenes are synthesized by plants and used as defense against pathogens and herbivory, we decided to expose cultures of Acremonium sp. DSM 24697 to sub-lethal concentrations of the terpenes geraniol, 2-phenethyl alcohol and linalool. The presence of transglycosylation products was evaluated in solid cultures of Acremonium sp. DSM 24697 with the flavonoids hesperidin or rutin as carbon sources. In the cultures with rutin as carbon source, no transglycosylation products were detected. In the cultures with hesperidin as carbon source, transglycosylation products were found in the presence of geraniol and 2-phenethylalcohol, while no products were detected with linalool. The products rutinosyl-geraniol and rutinosyl-phenethylethanol were identified in the supernatant of Acremonium sp. DSM 24697 by TLC and MALDI. These results supported our hypothesis that glycosylation could be a mechanism related to the defense system of the microorganism.