Biosphere 2 and Singularity 0047

The business side of an interstellar space ship. Perhaps a generational ship? I mean that several generations of a species would live and die inside the ship. Like people, plants and animals. A entire self sustaining ecosystem. Perhaps an entire forest resides in the ship. The forest is a filtration system for water, oxygen, co2, biomass you name it. Just like the amazing biosphere 2 in Arizona.