semi-business-related?
If you really want to use business-related, just use that. No semi- required. Related means:
connected in some way (MW)
E-business is definitely "connected in some way" to business, so just say,
I came from an academic background that is business-related.
Or, even better,
My academic background is business-related.
I would avoid trying to find the right hyphenated adjective as you've described it, and instead say something more simple and direct, such as, "My academic background includes a major in E-business."