I want to know if there is a possibility of a serial communication between a web interface in PHP and my arduino uno.
Maybe. PHP can communicate with the serial port. Your Arduino can communicate with the serial port. Whether you can connect your Arduino to the serial port of the server that PHP is running on remains to be seen.
Typically, the Arduino would be used as a web server, and the communications would be via http, and no PHP would be involved.
Or the Arduino would be a client, making GET requests to the server, but then there is no user interface.