No company will buy snake venom from a private party. Most labs in need of venom have an established, or experienced sources or they have their own stock of snakes in which they can obtain their venom. Contamination is a major concern and the extraction of venom if not done properly can cause many serious issues.In many cases thete is a need for special permits.
I would check your local laws and study with a Herpetologist to get a job at a lab. This is something that should not be taken lightly as I have seen many experienced handler including Bill Haast who I had know for many years through the Miami Serpentarium, get bitten and almost die. Joan