Separation of colour compounds from lipase in fermentation supernatant by diafiltration

Summary

Extracellular lipase was produced by growing Geotrichum candidum. A simple optical method was developed to quantify the dark-brown compounds formed during medium preparation and fermentation. The size of these molecules was in the fractionation range of Sephadex G-50. Diafiltration trials were done to screen ultrafiltration membranes for the most efficient decolonization of the cell-free lipase solution. Membranes were identified which reduced the colour by 80% with less than 5% loss of lipase activity after 4 volume exchanges in continuous diafiltration.