Chromium uptake from aqueous effluents by immobilized Baker's yeast

Abstract

Baker’s yeast immobilized in alginate was used to take up chromium from effluents. Chromium in aqueous solutions were used in different concentrations. To evaluate the viability and efficiency the baker’s yeast for chromium uptake from effluents three experiments done in two differents reactor systems: first in system 1 at 17.5 ml/s and with 10, 20, 25 and 30 mg/l Cr; second in system 2 at 38.7 ml/s with 20 mg/l Cr; third in system 2.1 at 6.65 ml/s and with 20, 30 and 40 mg/l Cr. The efficiency of chromium uptake varied between 86 and 100 %.

Biosorption of Heavy Metals by Candida albicans

“…In an experiment conducted in the absence of the yeast, the concentration of Cr(VI) of the samples decreased by about 14% in earth and 6% in water (data not shown), which may be caused by native microflora and reducers present in contaminated samples or components. The removal capacity of Cr(VI) by the fungus is equal or better than that for other yeasts reported such as C. maltose RR1 [19], with the removal of Cr(VI) by C. tropicalis [29]; the strains P. jadinii M9 and P. anomala M10, for Cr(VI) reduction [33]; for contaminated soil for bioremediation of Cr (VI) [45]; for Aspergillus niger [47]; and different yeasts [52].…”

Efficiency assessment of Common Effluent Treatment Plant (CETP) treating tannery effluents

“…These organisms were isolated from CETP and showed tolerance to high levels of Cr (VI), which may be exploited for removal of chromium in the field conditions. Several other investigators suggest similar strategy for remediation of chromium (Menezes et al 1998;Zetic et al 2001;Faisal and Hasnain 2003;Ksheminska et al 2003).…”

Reflexões em torno da impossibilidade definitiva na execução dos contratos administrativos

“…A dificuldade reside em saber como se compreende essa censura 93 , considerando que ao devedor não assiste um direito ao cumprimento e, como tal, ao credor não assiste um correspondente dever 94 . Mas, não existindo este dever, pode ainda assim conceber-se que o credor, nos quadros da relação obrigacional complexa, tenha sempre um dever acessório de colaboração, fundado na boa fé 95 . A falta de colaboração do credor (que se pode traduzir na simples recusa da prestação) constitui, assim, ato ilícito, presumindo-se a culpa (artigo 799.º/1 CC) 96 .…”