The OOIL video on oil extraction was pretty impressive. They inject some proprietary gas into a container of algae mix and I guess that causes the algae cell walls to break apart causing oil to rise to the top and biomass to sink to the bottom. I guess the next question is what exactly is that gas, is it inexpensive to acquire or make and is it something the EPA would allow to be used on a commercial scale.. if it is very toxic it may face some resistance especially if the process involves releasing it back to the atmosphere or risk leaking back to the atmosphere.