What exactly do you want? Get your coment auto approve from .edu? Or make your .edu site/blog have auto approve comment setting?
i don't know how to create automated bots to get auto aproved .edu links. its a tough thing to get some high PR .Edu links and making them auto approved is the toughest.
yes, .edu backlink is not special like many seoer said (maybe because they want to sell their backlink service easier). I remember that Matt Cutt said more than 1 time that .edu and .gov backlink is just like any other backlink.
edu backlinks means backlinks (hyperlinks which are pointing to your website) from websites with .edu domain. A backlink is considered as vote of confidence towards your website. And, edu websites are considered as authority websites. So, if you are getting backlink from .edu website this can give a good boost in your SERP rankings.
You can't make it auto approve, it all depends on the blog settings. My tip for you is to only get back link from high quality EDU / GOV links.