[General] IN the world vs. OF the world

[sorkroto]

While I was reading a document, I found one missing preposition. The sentence was: I am happy to see the keen interest of our young students to become a vital part of this very soon to be the biggest industry [ ] the world.
I read it fast and "in" came first out of my mouth. "in the world" sounded okay to me. However, "of" came up as an afterthought. Is there a distinct rule that seperates the areas of "in" and "of" when they're used like this, with "the world?" Or is this simply a matter of colloquial expression? :-o And would you be so kind as to show me some examples?

 

[Verona_82]

Hi.
Please note I'm not a teacher.

After superlatives, in is often used with a word referring to a place or group.

the best in the world/ in the team / in the family/ in the hotel / in the class etc.

of is often used with periods of time, plurals and pronouns

the best of all / of us / of them / of the men etc.

You can also say the world's best / biggest / fastest etc.