I think it starts with picking through some papers for minor cannabinoid targets that have been studied enough to elucidate the pathway. I’ve been paging through Natural Products Reports, v33, 12, 2016, p1347-1448 for inspiration.
As long as there’s one that’s an enzymatic step away from common cannabinoids, or other commercially available feedstocks, jockey its into a hosts DNA (I know jack all about when to use E. coli or yeast or other), feed it the precursors and all the metabolites needed, incubate, extract, purify and characterize.
I hope I didn’t butcher that too much. My ex was the gene-jockey.
So I guess for this to start, there would have to be a published pathway, and a decently accessible enzyme.