Learn Polish: Ten surowiec pochodzi od lokalnego producenta. - This raw material comes from a local manufacturer.

In Polish, the preposition you use with pochodzić (to come from / originate) depends on the source. We use z + Genitive for geographical places (like z Polski), but we use od + Genitive when the source is a person, a business, or a specific entity, like a producent (manufacturer).

What case is lokalnego producenta and why?

It is in the Genitive case. The preposition od always requires the Genitive. For masculine nouns referring to people or entities (like producent), the Genitive noun ending is -a, and the adjective takes the -ego ending (lokalnego).

Could I use the verb przychodzi instead of pochodzi here?

Not really. Pochodzić is used for origins, meaning "to originate from" or "to be sourced from." If you used przychodzi, it would mean the material is physically in transit or arriving right now (like a package in the mail), rather than describing its permanent origin.

How do I know the gender of surowiec (raw material)?

You can tell it is a masculine noun because it pairs with the masculine word ten (this). If it were neuter, it would use to, and if it were feminine, it would use ta.