Learn Portuguese (Portugal): O filme é mais interessante do que o livro. - The movie is more interesting than the book.

You use the pattern mais + [adjective] + do que. Here, we place the adjective interessante right in the middle to get mais interessante do que (more interesting than).

Can I just use que instead of do que for "than"?

Yes, you can! Both do que and just que are correct and mean exactly the same thing in this context. You could say mais interessante que o livro, though do que is extremely common in European Portuguese.

Why is the verb é used here instead of está?

We use é (from the verb ser) because being interesting is treated as an intrinsic, core quality of the movie. You use ser for permanent or defining traits, and estar for temporary states.

Would the word interessante change if we were comparing feminine nouns instead?

No. While most adjectives in Portuguese change their ending to match the gender of the noun, adjectives ending in -e (like interessante, inteligente, or grande) are neutral. They stay exactly the same for both masculine and feminine nouns, only adding an -s if the noun is plural.