Cilj rada bio je istražiti mogućnost uklanjanja kationskog bojila malahitnog zelenila (MZ) iz modelnih otopina bojila i sintetske otpadne vode biosorpcijom na otpadnu inaktivnu biomasu gljive Ganoderma applanatum. Provedeni su šaržni adsorpcijski eksperimenti, kako bi se istražio utjecaj različitih čimbenika na proces biosorpcije: koncentracija biosorbensa (0,5 – 5 g/L), vrijeme kontakta (1 – 120 min), početna koncentracija bojila (10 – 100 mg/L) i pH ( 4 - 10). Povećanje koncentracije biosorbensa dovelo je do povećanja postotka uklanjanja MZ te smanjenja količine adsorbiranog MZ po gramu biosorbensa. Ravnotežno stanje postignuto je unutar 120 min., pri čemu se proces biosorpcije odvijao vrlo brzo u prvih 30 minuta, dok se u kasnijim fazama usporavao dok nije postignuta ravnoteža. Proces biosorpcije bio je ovisan o koncentraciji MZ. Povećanje početne koncentracije bojila od 10 do 100 mg/L praćeno je povećanjem količine MZ adsorbiranog po gramu biosorbensa (od 7,79 mg/g do 74,64 mg/g) te smanjenjem postotka uklanjanja bojila. pH vrijednosti veće od 7 pogoduju biosorpciji MZ na inaktivnu biomasu G. applanatum, što se očituje većom količinom bojila adsorbiranog po jedinici mase biosorbensa, kao i većem postotku uklanjanja bojila. Freudlichov ravnotežni model bolje opisuje proces biosorpcije MZ na inaktivnu biomasu G. applanatum, u odnosu na Langmuirov model. Kinetiku biosorpcije pri primijenjenim eksperimentalnim uvjetima bolje opisuje kinetički model pseudo-drugog reda, u usporedbi s modelom pseudo-prvog reda. Nešto veća količina bojila adsorbirana je po gramu biosorbensa, pri uklanjanju iz sintetske otpadne vode s dodatkom bojila, u odnosu na modelnu otopinu bojila. The aim of this work was to investigate the possibility of removing the cationic dye malachite green (MG) from model dye solutions and synthetic wastewater by biosorption on inactive waste biomass of the fungus Ganoderma applanatum. Batch adsorption experiments were performed to investigate the influence of various factors on the biosorption process: Biosorbent concentration (0.5 - 5 g/L), contact time (1 - 120 min), initial dye concentration (10 - 100 mg/L), and pH (4 - 10). An increase in biosorbent concentration resulted in an increase in the percentage of MG removal and a decrease in the amount of MG adsorbed per gram of biosorbent. The equilibrium condition was reached within 120 minutes, and the biosorption process was very fast in the first 30 minutes, while it slowed down in the later stages until equilibrium was reached. The biosorption process was dependent on the concentration of MG. An increase in the initial dye concentration from 10 to 100 mg/L was accompanied by an increase in the amount of MG adsorbed per gram of biosorbent (from 7.79 mg/g to 74.64 mg/g) and a decrease in the percentage of dye removal. pH values above 7 favor biosorption of MG on the inactive biomass of G. applanatum, as indicated by a greater amount of dye adsorbed per unit mass of biosorbent and a higher percentage of dye removal. The Freudlich equilibrium model better describes the process of biosorption of MG on the inactive biomass of G. applanatum compared to the Freundlich model. The kinetics of biosorption under the applied experimental conditions is better described by the pseudo-second-order kinetic model than by the pseudo-first-order model. A slightly larger amount of dye per gram of biosorbent was adsorbed in the removal from synthetic wastewater with dye addition than in the model dye solution.