Class 'GearmanClient' not found. Extension gearman.so installed already

Question

I am getting below error in my Symfony 2 Application.

Fatal error: Class 'GearmanClient' not found

More Info:

1. Result from php -m lists gearman.

   Meaning: Gearman Extension is installed.
   

2. Result from php --info | grep gearman:

   /etc/php.d/40-gearman.ini
   gearman
   gearman support => enabled
   libgearman version => 1.1.12      
   

   Meaning: Gearman Extension is installed.
   

3. I also made a new file with following code:

   <?php
     $gmc = new GearmanClient();
     $gmc->addServer('localhost');
   
     print $gmc;
   ?>
   

   which outputs on the webpage:

   Catchable fatal error: Object of class GearmanClient could not be converted to string in /var/www/test-gearman/gearman.php on line 5
   

   There are no errors like GearmanClient not found.

   Meaning: GearmanClient is found by the test application.
   

What I don't understand is:

Now that gearman extension is installed and GearmanClient is even found by the test application. Why is my symfony application throwing this error.

I am using supertag/gearman-bundle.

Thanks in advance. I really appreciate any help.