The permissions settings for the projects are somewhat different from the wiki and blog post ones.

You can select which roles can create projects from the front-end, but there isn't any option for the editing part. The reason is that, by default, the projects are editable by:

• All members assigned to the project itself;
• Author of the project;
• Administrators.

During the creation of a projects, the creator can disallow the members of the projects to edit it. So only himself and the administrators will be able to edit it. To do this, the user has to check this option during the process of the project creation: