Isn't anywhere close to how it would work, and even if it had worked either way, there'd have been clear and detailed documentation in the court records with the approval of the judge.
How it would work, and this was an option in the APA and SISP had some company wanted to purchase BioAmber as a going concern, is the funds from the purchase, whatever they were, would pay off as much of the debt as possible in ranked order. The common stock of the company would be cancelled, and new stock issued to sell for capital for operations and growth.
Ever seen a company buy the shares of a bankrupt company and then turn right around and sell them? Nope. There's a reason for that. They don't have to, and it would be stupid to do so.