Use of Walnut Shell Powder to Inhibit Expression of Fe2 -Oxidizing Genes of Acidithiobacillus FerrooxidansReport as inadecuate




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1

Department of Biological and Environmental Engineering, Hefei University, Hefei 230601, China

2

School of Public Health, Anhui Medical University, Hefei 230032, China





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Author to whom correspondence should be addressed.



Academic Editors: Nicholas Frederick Gray and Panagiotis Karanis

Abstract Acidithiobacillus ferrooxidans is a Gram-negative bacterium that obtains energy by oxidizing Fe2+ or reduced sulfur compounds. This bacterium contributes to the formation of acid mine drainage AMD. This study determined whether walnut shell powder inhibits the growth of A. ferrooxidans. First, the effects of walnut shell powder on Fe2+ oxidization and H+ production were evaluated. Second, the chemical constituents of walnut shell were isolated to determine the active ingredients. Third, the expression of Fe2+-oxidizing genes and rus operon genes was investigated using real-time polymerase chain reaction. Finally, growth curves were plotted, and a bioleaching experiment was performed to confirm the active ingredients in walnut shells. The results indicated that both walnut shell powder and the phenolic fraction exert high inhibitory effects on Fe2+ oxidation and H+ production by A. ferrooxidans cultured in standard 9K medium. The phenolic components exert their inhibitory effects by down-regulating the expression of Fe2+-oxidizing genes and rus operon genes, which significantly decreased the growth of A. ferrooxidans. This study revealed walnut shell powder to be a promising substance for controlling AMD. View Full-Text

Keywords: walnut shell powder; acid mine drainage; Acidithiobacillus ferrooxidans; rus operon walnut shell powder; acid mine drainage; Acidithiobacillus ferrooxidans; rus operon





Author: Yuhui Li 1, Yehao Liu 2, Huifang Tan 1, Yifeng Zhang 1 and Mei Yue 1,*

Source: http://mdpi.com/



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