Yes.

Although Open Source Portfolio runs in and depends on the base Sakai collabortative learning environment, you can enable and use OSP tools without turning on or using any Sakai collaboration or course tools.

Alternatively, you can enable and use only those Sakai tools that may be useful in your specific portfolio environment, for example, Sakai's announcements, mailling list/archive or calendaring tools.

Because OSP lives in Sakai, together they give you the opportunity to provide users with a fully-integrated collaborative learning and portfolio environment.

Learn more about the Sakai Project.