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目的:探讨不同碳氮源对胶质芽孢杆菌GSY -1的生物脱硅效果的影响.方法:采用单因素试验并结合方差分析确定影响GSY -1生物脱硅的碳氮源种类及浓度,通过回归实验及响应面分析进一步优化培养条件,然后利用10L发酵罐进行放大实验验证.结果:研究发现,乳糖和尿素对GSY -1生物脱硅的影响均显著,其中尿素10g/L及乳糖13g/L时,培养液中铝硅比(A/S)分别可由2.84提高到5.45和5.42,通过响应面优化实验,确定尿素10.35g/L、乳糖12.60g/L时,菌株GSY -1的脱硅效果最佳,铝硅比由2.84提高到5.67,增幅达99.65%.经10 L发酵罐放大实验,测得浸矿后的铝硅比为5.07,较浸矿前提高78.52%.结论:乳糖和尿素对胶质芽孢杆菌GSY -1脱硅效果影响显著,响应面法可有效用于GSY -1菌株脱硅条件的优化. 相似文献
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Nutrient mobility in variable- and permanent-charge soils 总被引:5,自引:2,他引:3
Variable-charge (v-c) and permanent-charge (p-c) soils differ fundamentally with regard to many nutrient-cycling processes. Variable-charge soils are more common in the tropics than in temperature zones because their formation requires desilication, which proceeds fastest in warm, moist climates. The dynamics of nutrient mobility tend to be more complex in v-c than in p-c soils. For example, theory predicts that, as pH of v-c soils decreases, cation exchange capacity (CEC) also decreases and anion exchange capacity (AEC) increases. If AEC exceeds CEC, cations such as ammonium and potassium will be more mobile than anions such as nitrate; this is the reverse of the situation in p-c soils, on which most of our knowledge of nutrient cycling is based. Variable-charge surfaces sorb phosphorus, creating plant nutritional problems throughout large areas of the humid tropics. Desilication, the same process that creates v-c surfaces, results also in stable aggregation, creating soils that retain water, yet drain rapidly and resist erosion. The Soil Taxonomy system incorporates information on mineralogy, texture, and organic matter content, and therefore provides insights into patterns of charge chemistry and nutrient cycling across a wide range of soil types. 相似文献
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