BioAmber, Inc., had guaranteed much of the debt that Sarnia carried, which makes sense when you consider the parent company was the one that could sell stock and raise money to pay debt.
They chose the path because they'd been delisted from the 2 exchanges and the stock price had tanked, making raising more money to cover their continuing losses practically impossible. They couldn't get any more credit, either, since they had a pile already and nobody was going to loan more.
The folks that bought in that offering still had an opportunity for profit, since the PPS was still above the final offering price and the offering did have warrants attached. They surely didn't make much, though.
With respect to the price of the liquidation, remember that BioAmber had never run the plant to its alleged capacity and lost money the whole time it ran. Those who bid on it at all took a considerable risk they could better with it, and while we know LCY is running it better after the purchase and investing in some fixes, we don't know if they're making a profit with it either.