(I can't comment, so I'll write my comment here:)
It seems that pysfst is currently outdated (anyone please correct me if I'm wrong). I also couldn't install pysfst via pip. Like @jeevan, I also tried to build pysfst from the sources (http://download.gna.org/pysfst/pysfst-1.1.3.tar.bz2), but failed.
I think the problem is that according to http://gna.org/projects/pysfst, pysfst supports SFST version 1.1. The latest SFST version at this time is 1.4.7a. The Ubuntu packages sfst
and libsfst1-4
support SFST version 1.4.6g. Compiling pysfst requires SFST 1.1 sources, which are currently not available from the SFST home page (http://www.cis.uni-muenchen.de/~schmid/tools/SFST/).