Finally it is possible to enable USB OTG functionality on the Motorola Moto G
However keep in mind that the USB OTG will work only inside the application. However if you want to open a file in another app, just copy the file to the device or your micro SD card.
Download the app from here. Since it is an APK file you will have to side load it on your Motorola Moto E. For that copy it to your Moto E and open a file explorer. Then browse to the folder that contains that file and open the APK.
Install the file and you will find it in the application drawer. Open it and enable the USB OTG on it to enjoy the functionality.