A biodegradable bi-component fiber may include a polyhydroxyalkanoate and/or polylactic acid with cellulose acetate and/or plasticized cellulose acetate for use in a filter material configured for use in a filter of a smoking article. The bi-component fiber may have a sheath-core construction where one component of the bi-component forms the core, and the other component forms the sheath of each fiber. A filter made in accordance with this design may also include non-biodegradable material.