Chromium Bioremoval from Tannery Industries Effluent By Aspergillus oryzae

Recently laboratory Studies had recognized the capability of alge , fungi , and bacteria in the removal of heavy metals from industrial effluent . In this research , growth of Aspergillus oryzae in the tanning house effluent , and its capability in chromium bioremoval were assessed . Aspergillus oryzae can grow in different concentration of Cr+ , 120-1080 mg/L . Maximum biomass growth and chromium removal rate at pH,3.3 , Cr+3 concentration equal to 240mg/L and inoculum size equal to 0.12% (dry weight) were 0.25% ( dry weight ) and 94.2% respectively. Effects of various factors such as pH, temperature, shaking velocity and nutrients were also investigated. At optimum conditions ( ie: pH=5; temperature=30ºC , shaking velocity= 150rpm, and nitrogen source of dihydrogen ammonium phosphate concentration=0.3%), biomass growth and chromium removal rate were found to be 0.45% of dry weight and 99.8%, respectively. Effect of detention time showed after 30h. biomass growth and chromium removal rate were 0.28% and 97.6% respectively . Statistical studies (anaylsis of varience) on factors such as pH, temperature, shaking velocity, type and concentration of nutrients on the “biomass growth” and “residual chromium” , showed that all of the factors had significant effects ( α = 0.05 , P < 00.1 ) .

کلیدواژه ها:

Tannery industries effluent ، Chromium ، Bioremoval ، Aspergillus oryzae