How to set email config different from 'mail', 'sendmail', or 'smtp'

In one of my projects in CI, I need to use Amazon SDK API instead of Amazon SMTP. I have created a PHP file at "application/config" and add the following code to email.php. 

My Amazon SMTP configuration sending correct email but now as per my requirement, I need to change SMTP to SDK API.

I have searched many articles all showing CI email setup using SMTP in the configuration but not as SDK API using key & password.

My working SMTP configuration is shown below 

PHP Code:

$config['protocol']        = 'smtp'; // 'mail', 'sendmail', or 'smtp'
$config['smtp_host']    = 'mtp.example.com';
$config['smtp_user']    = '[email protected]';
$config['smtp_pass']    = 'xxxxxxxxxx';
$config['smtp_crypto']    = 'tls';
$config['smtp_port']    = '587';
$config['mailtype']    = 'html';
$config['newline']    = "\r\n"; 


Please suggest how to replace this SMTP configuration with Amazon SDK so that I can use a secret key and password. Instead of SMTP details.