Bioremediation of a wine distillery wastewater using white rot fungi and the subsequent production of laccase

Abstract

The aim of this work was to ascertain whether a submerged culture of a white rot fungus could be used to treat distillery wastewater, and whether the compounds present in the wastewater would stimulate laccase production. Trametes pubescens MB 89, Ceriporiopsis subvermispora, Pycnoporus cinnabarinus and UD4 were screened for their ability for the bioremediation of a raw, untreated distillery wastewater as well as distillery wastewater that had been pretreated by polyvinylpolypyrrolidone. Suitability of each strain was measured as a function of decreasing the chemical oxygen demand (COD) and total phenolic compounds concentration and the colour of the wastewater, while simultaneously producing laccase in high titres. After screening, T. pubescens MB 89 was used further in flask cultures and attained 79 +/- 1.1% COD removal, 80 +/- 4.6% total phenols removal, 71 +/- 1.6% decrease in colour at an absorbance of 500 nm and increased the pH from 5.3 to near-neutral. Laccase activity in flask cultures peaked at 4,644 +/- 228 units/l, while the activity in a 50 l bubble lift reactor peaked at 12,966 +/- 71 units/l. Trametes pubescens MB 89 greatly improved the quality of a wastewater known for toxicity towards biological treatment systems, while simultaneously producing an industrially relevant enzyme.