BACKGROUND: The paper discusses biosorption of microelements by a freshwater macroalga Pithophora varia Wille to produce biological feed supplement for livestock. The biomass was enriched with microelements recommended by feeding standards in a single and a multi-metal system.
RESULTS: The equilibrium of biosorption was described by using a Langmuir model and the following values of the maximum biosorption capacity in the single-metal system were obtained: Zn(II), 61.1 mg g−1; Co(II), 52.3 mg g−1; Cu(II), 55.7 mg g−1; and Mn(II), 38.3 mg g−1. The average value of maximum biosorption capacity expressed in molar units for all the cations was equal 1.7 ± 0.2 meq g−1, suggesting chemical rather than physical biosorption. It was also found that the mechanism of biosorption was due to cation exchange of alkali and alkaline earth metals with microelements. The biomass was also enriched with microelements in multi-metal system. The total metal ion binding capacity in the multi-metal system was two-fold lower than in the single-metal system and was 0.90 meq g−1 in the preparation for laying hens and 0.95 meq g−1 in the supplement for swine.
CONCLUSION: Finally, the level of supplementation of livestock feed (with enriched single- and multi-metal system macroalga), to cover 25% of total requirements for microelements, according to feeding standards, was provided. Copyright © 2008 Society of Chemical Industry