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Adsorption of the insecticidal protein of Bacillus thuringiensis subsp. kurstaki by minerals: effects of inorganic salts
Author(s) -
Fu Qingling,
Wang Wanqin,
Hu Hongqing,
Chen Shouwen
Publication year - 2008
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1111/j.1365-2389.2007.00977.x
Subject(s) - goethite , bacillus thuringiensis , chemistry , adsorption , sorption , montmorillonite , kaolinite , environmental chemistry , salt (chemistry) , toxin , nuclear chemistry , ion exchange , inorganic chemistry , mineralogy , biochemistry , organic chemistry , ion , biology , bacteria , genetics
Summary The persistence of the insecticidal protein of Bacillus thuringiensis ( Bt ) is enhanced by the reactivity with soil particles and may constitute a hazard to the soil ecosystem; however, studies on the fate of the Bt toxin in soil, especially in the presence of inorganic salts, are limited. The effects of different concentrations of KNO 3 , KH 2 PO 4 and NH 4 H 2 PO 4 on the adsorption of Bacillus thuringiensis toxin by kaolinite, montmorillonite, goethite and silicon dioxide were investigated. Results showed that small salt concentrations tended to enhance toxin adsorption, whereas large concentrations (> 10 mmol litre −1 ) inhibited sorption. Similar results were observed regardless of the order in which toxin and inorganic salt were added. The degree to which individual salts affected adsorption decreased in the sequence for minerals, goethite > kaolinite ≥ montmorillonite > silicon dioxide, and for ions, H 2 PO 4 − > NO 3 − , NH 4 + > K + . Our results indicate that inorganic salts can markedly influence the adsorption of Bt toxin by soil minerals. This investigation will help in evaluating the behaviour and fate of Bt toxins in the soil environment.