REMOVAL OF TRACE CD(II) FROM AQUEOUS-SOLUTIONS BY FUNGAL ADSORBENTS - AN EVALUATION OF SELF-IMMOBILIZATION OF RHIZOPUS-ORYZAE

Abstract

Rhizopus oryzae are grown in the fermenter as discrete and nearly spherical pellets. The pellets' size and structure suggest that more agitation produces smaller and more compact pellets. In this study, the agitation intensity in the fermenter is changed to produce the suspension mycelium and pelletized mycelia with various sizes. Acid-washing and heat treatments are applied to deactivate the fungi. Experimental results indicate that acid-treated mycelia are preferential to either fresh or heat-treated pelletized mycelium for use in the binding of Cd(II) ions. Based on engineering and economic considerations, this study screens an optimum size of pellet to be 3.8 mm which is formed under 2-day pre-cultivation and 5-day harvest in a fermenter at 300 rpm of agitation.