trim|valid_email not working in validation

PHP Code:

$this->form_validation->set_rules('xname','','trim|required');
$this->form_validation->set_rules('xemail','','trim|valid_email'); 


Hi, in the above code the first line is trimming 'xname' as expected. But the second line to not remove spaces in the beginning of 'xemail'. I get validation success and I insert the data in a database. When looking in the database the spaces are still there in the beginning of the 'xemail' but gone in 'xname'.  Any idea what is causing this?