It isn't configured to run as a user explicitly unless the individual setting it up/installing it did so. If it's been running as root, just chown the entire directory to the desired user and set the start script to include su - <desired user> when it invokes it.
We usually run all Talend services never under a root user. I suggest you create a user + group like tisadmin or similar and do su - tisadmin -exec 'your script'
