A dispenser pump comprising: an actuator head defining a dispensing channel and having axially extending sidewalls with at least one rotational stopper formed thereon; a closure body having a floor extending between cylindrical sidewalls, said floor having a central recessed portion defined by tubular walls terminating in a ledge defining an inlet aperture; an insert overlaid atop the closure body between the cylindrical sidewalls thereof, and characterized in that said insert includes a central cylindrical member, fitted within and substantially conforming to the recess, having an inlet aperture at a bottom-most edge and a sinuous ridge formed on an outerfacing thereof; and in that the dispenser pump further comprises a deformable, resilient bellows coupled to a peripheral groove formed in the insert so as to define a pump chamber, said deformable bellows including an upward connection tube forming an outlet from the pump chamber with an outlet valve held therein, said bellows being coupled to the actuator head so as to allow an axial actuation movement that temporarily alters a volume of the pump chamber; a sealing plug carried partially within the cylindrical member and sized to seal the inlet aperture of the insert, said sealing plug including a keying projection sized to seal the inlet aperture of the closure body; wherein, in response to rotary movement, the sinuous ridge cooperates with the closure body to displace or seal the sealing plug relative to the inlet aperture of the insert; and wherein the actuator head, the closure body, the bellows, and the sealing plug are made from recyclable thermoplastics. an actuator head defining a dispensing channel and having axially extending sidewalls with at least one rotational stopper formed thereon; a closure body having a floor extending between cylindrical sidewalls, said floor having a central recessed portion defined by tubular walls terminating in a ledge defining an inlet aperture; an insert overlaid atop the closure body between the cylindrical sidewalls thereof, and characterized in that said insert includes a central cylindrical member, fitted within and substantially conforming to the recess, having an inlet aperture at a bottom-most edge and a sinuous ridge formed on an outerfacing thereof; and in that the dispenser pump further comprises a deformable, resilient bellows coupled to a peripheral groove formed in the insert so as to define a pump chamber, said deformable bellows including an upward connection tube forming an outlet from the pump chamber with an outlet valve held therein, said bellows being coupled to the actuator head so as to allow an axial actuation movement that temporarily alters a volume of the pump chamber; a sealing plug carried partially within the cylindrical member and sized to seal the inlet aperture of the insert, said sealing plug including a keying projection sized to seal the inlet aperture of the closure body; wherein, in response to rotary movement, the sinuous ridge cooperates with the closure body to displace or seal the sealing plug relative to the inlet aperture of the insert; and wherein the actuator head, the closure body, the bellows, and the sealing plug are made from recyclable thermoplastics.