Root LG E450

Actually this method can be apply with lg e460 too.

1) Download SuperSU from the android market
2) Grant Permission for SuperSU to work ( Press the left button on the chinese dialogue )
3) When prompted to update the SU binary, tap on Update
4) Once Update is over, swipe to the Settings tab and select, "Install SuperSU in /system" , option.
5) After Phone restarts, you will find the Chinese SuperUser is not present, but the SuperSU is present.
6) now execute the following command in your terminal or command prompt

---------- For Windows Users ---------------

adb.exe shell "su -c 'mount -o remount,rw /system'"

adb.exe shell "su -c 'rm /system/bin/su'"

adb.exe shell "su -c 'rm /system/xbin/su'"

------------- For Mac/Linux Users ------------

adb shell "su -c 'mount -o remount,rw /system'"

adb shell "su -c 'rm /system/bin/su'"

adb shell "su -c 'rm /system/xbin/su'"

7) Now Open SuperSU and once again update SU Binary.

Thanks to subho007