Best approach for basic PHP DB session data storage

I’ve decided to switch from PHP’s native session management based on $_SESSION to use my own, due to many different issues I’ve had so far with PHP’s possibilities, and also because I’m building an API that must be compatible with mobile app requests; so I cannot rely on $_SESSION anyway.
I know that there are frameworks as symfony etc. out there for this, but using sth like that for these baby operations would be overkill.

Grunt serve + PHP?

I’m starting my first project with yo + grunt + angular.js.
I have a service which needs to read some data from my server; I built it using angular $http service.
I’ve also built a RESTful web service (implemented in PHP, but it could be Java, C, Perl, …, it doesn’t matter) which exposes an API to get the data.
The server from which grunt serves my ng-app is currently (and probably will ever be) the same from where the PHP web service is run (by apache).