The Effect of various factors on laccase production of microorganisms

Many white-rot fungi, including Trametes versicolor, produce extracellular copper-containing phenoloxidase, called laccase. This enzyme has potential applications in the dye, paper or textile industries, as well as for the degradation of various xenobiotics, which are recognized as environmental pollutants. In the presence of inducers many white rot fungi excrete large amount of laccase into the medium. In this study, Cu, lignocellulosic materials and cheese whey have been assayed for their ability to enhance laccase production in liquid cultures of Funalia trogii and Trametes versicolor. Addition of, especially, 0.5-1.0 mM of Cu into the metal free stock and distilled water cultivation medium increased the activity of laccase. The lignocellulosic materials also positively affected the laccase activity of these two fungi. The potential use of fungal pellets for laccase enzyme production was also examined. The pellets were used in a repeated batch mode for 5 d. The laccase production ability of pellets remained high and stable for 5 d. Cu supplementation greatly improved laccase activity. Additionally, not only the pellets could be used several times but also high laccase activity was obtained. Cheese whey was also used as a laccase production medium in a repeated batch operation. The results suggest the potentiality of these two white rot fungi in laccase production. It is also possible to induce the laccase activity of these fungi by carefully choosing the supplementation material such as Cu. From these results, it can also be stated that fungal pellets can excrete high amount of laccase enzyme in a repeated batch mode. KEYWORDS: Laccase, white rot fungus, Funalia trogii, Trametes versicolor, copper, lignocellulosic materials