See this thing below? This is from the opensecrets page that you linked. Scroll down to the bottom of that "opensecrets" page and you will see this. Yes Bernie received that money from individuals.

As I said before: Individuals are like you and me working anywhere. If I work for the Gas industry but feel like contributing to Bernie, that only proves that EVEN people - who are working for industries that support PACs that contribute to Hillary - are actually supporting Bernie on their own because they believe in him.