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【目的】比较主要岩溶环境因子对土壤细菌、真菌和放线菌胞外碳酸酐酶(CA)活性的影响,为评价3类微生物CA在加强碳酸盐岩溶蚀过程中的作用提供依据。【方法】从桂林毛村岩溶区土壤中筛选出产胞外CA较高的细菌、真菌和放线菌菌株,比较不同温度、p H及不同浓度岩溶环境常见离子下其胞外CA活性。【结果】细菌、真菌和放线菌均在30℃时胞外CA活性最高,且峰值在3类微生物中表现为细菌>真菌>放线菌。细菌胞外CA活性最适温度范围是20~30℃,在真菌与放线菌中为20~40℃。细菌、真菌和放线菌胞外CA活性最适p H分别为8.2,6.2和7.2,峰值在3类微生物中表现为真菌>细菌>放线菌,在真菌与细菌中比在放线菌中分别高出40.0%、33.1%。锌和钴对细菌、真菌胞外CA活性促进作用最大,钙对放线菌胞外CA活性促进作用最大。硝酸根对3类微生物胞外CA活性促进作用均较大。8种受试离子中,3类微生物中胞外CA活性峰值均表现为细菌>真菌>放线菌。【结论】岩溶环境更有利于细菌胞外CA活性的表达,其次是真菌与放线菌。
【Objective】 The objective of this study was to compare the extracellular carbonic anhydrase (CA) activity of soil bacteria, fungi and actinomycetes with the main karst environmental factors, and to provide basis for evaluating the role of CA in the enhancement of carbonate dissolution. 【Method】 The strains of bacteria, fungi and actinomycetes with higher extracellular CA were screened from the soil of Kumcity karst area in Guilin. The extracellular CA activities of the cells were compared under different temperatures, p H and common ions in different concentrations of karst environment. 【Result】 The results showed that all the bacteria, fungi and actinomycetes had the highest activity of extracellular CA at 30 ℃, and the peak appeared as bacteria> fungi> actinomycetes in the three kinds of microorganisms. The optimum temperature range of bacterial extracellular CA activity is 20-30 ° C and 20-40 ° C for fungi and actinomycetes. The optimal extracellular CA activity of bacteria, fungi and actinomycetes were 8.2, 8.2 and 7.2, respectively, and the peak appeared as fungi> bacteria> actinomycetes in three kinds of microorganisms, and in fungi and bacteria than in actinomycetes Respectively higher than the 40.0%, 33.1%. Zinc and cobalt have the greatest promotion effect on extracellular CA activity of bacteria and fungi, and calcium has the greatest promotion on extracellular CA activity of actinomycetes. Nitrate promoted the extracellular CA activity of three kinds of microorganisms. Of the 8 kinds of test ions, the peak of extracellular CA activity in all three kinds of microorganisms showed bacteria> fungi> actinomycetes. 【Conclusion】 Karst environment is more conducive to the expression of extracellular CA activity of bacteria, followed by fungi and actinomycetes.