Role of Wheat-Residue-Derived Char in the Biodegradation of Benzonitrile in Soil: Nutritional Stimulation versus Adsorptive Inhibition

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• 作者：Ping Zhang ; Guangyao Sheng ; Yucheng Feng ; and David M. Miller
• 刊名：Environmental Science & Technology
• 出版年：2005
• 出版时间：July 15, 2005
• 年：2005
• 卷：39
• 期：14
• 页码：5442 - 5448
• 全文大小：166K
• 年卷期：v.39,no.14(July 15, 2005)
• ISSN：1520-5851

文摘

Previous studies demonstrated that crop-residue-derivedchars are effective adsorbents for pesticides and substantiallyreduce their biodegradation in soils. In contrast, thenutrients in the chars may stimulate cell growth and henceenhance the biodegradation. This work investigated therole of a wheat-residue-derived char in the nutritionalstimulation and adsorptive inhibition of biodegradation ofbenzonitrile in a soil. The biodegradation was measured at78 mg/L of benzonitrile, an initial concentration muchhigher than the half-saturation constant of the degradingorganism (~18 mg/L). The degradation was much faster inthe extract of char-amended soil (CAS) than in those ofsoil and washed-char-amended soil (WCAS). The degradationwas also faster in CAS slurry than in slurries of soil andWCAS until ~88% of benzonitrile degraded in char-containingslurries, where the aqueous-phase concentration was~0.25 mg/L. Cell density was higher in extracts and slurriesin the presence of the char nutrients than in the absenceof them. Analysis of nutrient elements in extracts, alongwith measuring degradation in soil extract with nutrientsupplements and subsequent stepwise multiple-regression,suggested that the char nutrients stimulated cell growthand degradation of benzonitrile, for which P was primarilyresponsible. Further degradation of benzonitrile beyond88% in the presence of char was slow, suggestive of theadsorptive inhibition. The biodegradation of benzonitrilein CAS thus occurred through a fast-to-slow process, theformer step being due primarily to the stimulation bysoluble P of char and the latter phase to the adsorptiveinhibition.