The invention relates to a mixer assembly for agitating material in a digestion tank (1), comprising a drive unit (7, 8, 9) and an output shaft (10) extending from said drive unit, which output shaft is arranged to hang down into said digestion tank (1) rotatably suspended from the drive unit. According to the invention the mixer assembly (6) furthermore comprises a stabilizer (12) comprising a swivel (13) and at least one resilient element (14) connected to said swivel (13), the stabilizer (12) being connected to the lower end of the output shaft (10) of the mixer assembly (6) and being arranged to be connected to a floor (2) of said digestion tank.
