Learn Portuguese (Portugal): Este trabalho não me satisfaz.

In European Portuguese, object pronouns normally attach to the end of the verb with a hyphen. However, negative words like não (not), nunca (never), or ninguém (nobody) act as "magnets." When a negative word comes before the verb, it pulls the pronoun to the front, dropping the hyphen.

The verb form satisfaz looks irregular. What is the infinitive and how do I conjugate it?

The infinitive is satisfazer (to satisfy). Notice that it is just the prefix satis- attached to the highly irregular verb fazer (to do / to make). Compound verbs like this follow the exact same conjugation rules as their base verb. Since the "he/she/it" form of fazer is faz, the form for satisfazer becomes satisfaz.

Could I use the word emprego instead of trabalho in this sentence?

You could, but it shifts the focus slightly. Emprego refers specifically to your employment, position, or contract. Trabalho refers to the actual labor, tasks, or daily effort. Saying Este trabalho não me satisfaz implies that the actual tasks you are doing are unfulfilling, whereas emprego might imply you are unhappy with the position or company itself.

If I wanted to describe my own state of mind rather than what the job is doing to me, how would I rephrase this?