How are turboprops and other propeller planes pressurized?
Turboprops are actually turbine engines. They can produce bleed air just like turbine engines (e.g. turbofan). The bleed air can be used directly to pressurize the cabin, or it can drive another turbo compressor to pressurize fresh air from the outside:



Modern aircraft with supercharged piston engines simply use bleed air from a) the main engine's compressor or



b) the main engine's turbo charger



Another solution is to drive dedicated air compressors to pressurize the cabin. Typically this may be Roots blowers or centrifugal fans. They are mechanically driven from the main engine(s).



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