Enabling compression in .htaccess file is causing 500 internal error

This is the code I am adding to my .htaccess file for compression and browser caching and gzip.

# BEGIN WordPress
IfModule mod_rewrite.c
RewriteEngine On
RewriteBase /wordpress/
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /wordpress/index.php [L]
/IfModule

# END WordPress

ifModule mod_gzip.c
mod_gzip_on Yes
mod_gzip_dechunk Yes
mod_gzip_item_include file .(html?|txt|css|js|php|pl)$
mod_gzip_item_include handler ^cgi-script$
mod_gzip_item_include mime ^text/.*
mod_gzip_item_include mime ^application/x-javascript.*
mod_gzip_item_exclude mime ^image/.*
mod_gzip_item_exclude rspheader ^Content-Encoding:.*gzip.*
/ifModule

## EXPIRES CACHING ##
IfModule mod_expires.c
ExpiresActive On
ExpiresByType image/jpg "access 1 year"
ExpiresByType image/jpeg "access 1 year"
ExpiresByType image/gif "access 1 year"
ExpiresByType image/png "access 1 year"
ExpiresByType text/css "access 1 month"
ExpiresByType text/html "access 1 month"
ExpiresByType application/pdf "access 1 month"
ExpiresByType text/x-javascript "access 1 month"
ExpiresByType application/x-shockwave-flash "access 1 month"
ExpiresByType image/x-icon "access 1 year"
ExpiresDefault "access 1 month"
/IfModule
## EXPIRES CACHING ##

When I go to the dashboard>settings>permalinks and click save changes, this code disappears and only the first block remains and the 500 internal error gets resolved. But my website is still not compressed or cached or gzipped. I need those three things to speed up the site.