Super sorry for the delayed response my friend. We've been contacting our supplier to figure out some information!
We ourselves know for a fact there are multiple VG manufacturers. You can easily tell the difference in taste, color, and viscosity of the product itself.
In regards to the VG being related to bio-diesel production. This is the question that stumped us for a bit. We have never heard anything of the sort before and neither has our supplier of the product. So, in regards to that question our team is going to say no since we can't find any evidence to support it.
We hope this helps!