Can the Nginx mail server be used in replacement of Postfix?

I am a bit new to this. However, I have a small, fully functioning, unmanaged VPS server, rented from Linode.com, which is setup as a LEMP server, running Ubuntu 11.04, Nginx 1.0.2, MariaDB 5.2.6, PHP 5.3.6 (PHP-FPM), xcache 1.3.1, vBulletin 4.1.2, and Postfix which was setup using the following script:

###########################################################
# Postfix
###########################################################

# Installs postfix and configure to listen only on the local interface. Also
# allows for local mail delivery

{
echo "postfix postfix/main_mailer_type select Internet Site" | debconf-set-selections
echo "postfix postfix/mailname string localhost" | debconf-set-selections
echo "postfix postfix/destinations string localhost.localdomain, localhost" | debconf-set-selections
aptitude -y install postfix
/usr/sbin/postconf -e "inet_interfaces = loopback-only"
#/usr/sbin/postconf -e "local_transport = error:local delivery is disabled"

touch /tmp/restart-postfix
}

############################################################

Can the Nginx mail server be used in the same manner in replacement of Postfix?

If so:

(1) Is there good reason not to use the Nginx mail server in such a manner?

(2) What do I need to do in order to use the Nginx mail server instead of Postfix?

As a matter of information, I recently subscribed to Google Apps for the hosted domain. We need Postfix, or the Nginx mail server, only to send and receive email from our web applications.

Thank you.