科研之友
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摘要
Hexavalent chromium (Cr6+) is one of the most potent heavy metal pollutant released from various industries into water bodies. Most commonly used physico-chemical methods, for the removal of Cr6+ from waste waters are inefficient, expensive and also produces unmanagable toxic sludge. Recent studies showed that biosorption, based on metal-biomass interaction can be an alternative to commonly employed methods for Cr6+ removal from waste waters. Among the various biosorbent, bacteria, yeast, algae and fungi have potential for Cr6+ biosorption. In this study, Bacillus circulans MTCC 3161, Saccharomyces cerevisiae and Aspergillus :tiger were screened for high Cr6+ concentration tolerant strain isolation. It was found that, Bacillus circulans MTCC 3161 and Saccharomyces cerevisiae are resistant up to 800 ppm of initial Cr6+ concentration present in the fermentation media, whereas, Aspergillus niger can resist up to 900 ppm of initial Cr6+ concentration. Moreover, it was also found that Cr6+ resistant Aspergillus niger have better biosorption potential (48% at 800 ppm) than that of Cr6+ resistant Bacillus circulans MTCC 3161 and Saccharomyces cerevisiae (40% and 38% respectively at 800 ppm). Scanning Electron Microscopic studies of mycelia with spores of parent cells of Aspergillus niger, Cr6+ resistant Aspergillus niger and Cr6+ loaded Cr6+ resistant Aspergillus niger revealed that exposure of parent Aspergillus niger to high Cr6+ concentration induces morphological changes. Moreover, Cr6+ loaded Cr6+ resistant Aspergillus niger shows further changes in mycelial and hyphal morphology which occurs may be due to biosorption of Cr6+ onto Cr6+ resistant Aspergillus niger. Metal-biomass interaction was confirmed by Fourier Transform Infra Red (FTIR) spectroscopic study which also indicates the presence of hydroxyl, amine, amide, carbonyl or carboxyl groups, on cell wall of Aspergillus niger.
- 出版日期2010-7
