Treatment of the sugar refinery ion-exchange resins effluent with Phanerochaete chrysosporium

Abstract

Ion exchange resins produce a salt effluent with a high colour content and a high salt concentration. Some of the colourants can be removed by precipitation with lime. Colourants which are not removed can be degraded by microorganisms.

The white rot fungus Phanerochaete chrysosporium has been widely studied, due to its capacity of metabolising xenobiotics coming from several chemical and food industries. This organism has an enzymatic system related with lignin degradation, which was also shown to be able to degrade such compounds as DDT, lindane, pentachlorophenol, melanoidins, etc.

In the sugar industry, melanoidins and polyphenols are among the most important coloured compounds in the process, and appear in great quantities in the effluents from the regeneration of ion-exchange resins. The study was made at laboratory scale to investigate the possibility of using Phanerochaete chrysosporium in the removal of these compounds.

Growth studies performed in the effluent were made in order to optimize the colour removal (and the culture medium), varying several conditions - micronutrients, pH, salt content, carbon and nitrogen source, etc. In ideal conditions, 76% colour reduction and 81% polyphenolic compounds removal was obtained.