The picture <i>Joseph and his Brothers</i>, painted in 1657, was lined twice in the 18th century. The glue was apparently a welcoming substrate for molds threatening the paint layers. The molds were isolated and their enzymatic activities investigated in detail. The deleterious (lipolytic) activity of these molds, associated with the presence of glue as substrate, was proven to cease when the glue was removed. Therefore, the conservation consisted of efficient removal of only the glue using a new enzymatic preparation originating from Antarctic krill. After a short exposure, nearly all the glue was hydrolyzed. The minor glue residues were finally dissolved using amylase alone in order to protect the original impregnation of the canvas.