Laccase production by newly isolated white rot fungus Funalia trogii: Effect of immobilization matrix on laccase production

Abstract

The laccase production performance of newly isolated Funalia trogii (F. trogii) immobilized on low-cost activated adsorbents prepared from apricot stone was investigated in inexpensive molasses medium and compared with free pellets. The adsorbents were apricot stone-based activated carbon (AC), Cu-impregnated apricot stone-based activated carbon (Cu–AC) and Fe-impregnated apricot stone-based activated carbon (Fe–AC). Cu–AC and Fe–AC were prepared by chemical activation. The values of BET surface area (SBET), total pore volume (Vt), micropore surface area (Smic) and micropore volume (Vmic) which show the pore properties of the activated carbons were 133m2g−1, 0.105cm3g−1, 108m2g−1 and 0.056cm3g−1 for Cu–AC and 145m2g−1, 0.112cm3g−1, 117m2g−1 and 0.061cm3g−1 for Fe–AC, respectively. F. trogii attached well on all of these adsorbents. However, the fungus immobilized on Cu–AC produced much higher levels of laccase than the others. The laccase activity obtained in 5gL−1 molasses media after first cycle and mean laccase activity obtained after three cycles with fungus immobilized on Cu–AC were 29.23UmL−1 and 27.04UmL−1, respectively. These activities were only 0.25 and 0.39UmL−1 with free pellets. The crude laccase from immobilized culture could also decolorize the textile dyes.