DISCOVER: A facile structure-based screening method for vinyl compound producing microbes

Here we report a novel structure-based microbial screening method for vinyl compound discovery, DISCOVER (direct screening method based on coupling reactions for vinyl compound producers). Through a two-step screening procedure based on selective coupling reactions of terminal alkenes, the thiol-ene reaction (1(st) step of screening) and Mizoroki-Heck reaction, followed by iodine test (2(nd) step of screening), microbes producing vinyl compounds like itaconic acid (IA) can be isolated from soil samples. In the 1(st) step of screening, soil sources are plated on agar medium supplemented with an antimicrobial agent, α-thioglycerol (TG), and a radical initiator, VA-044 (VA). In the 2(nd) step of screening, vinyl compounds produced in the cultures are labelled with iodobenzene via the Mizoroki-Heck reaction, followed by an iodine test, leading to the detection and characterisation of labelled products. We evaluated the validity of DISCOVER using IA and its producer Aspergillus terreus. Experimental data supported our hypothesis that IA reacts with TG in the medium via the thiol-ene reaction and consequently, A. terreus rapidly forms colonies on the agar medium because of the loss of the antimicrobial activity of TG. Using DISCOVER, high throughput and selective isolation of A. terreus strains producing IA was possible from soils.