一株胶质芽胞杆菌对磷矿石风化作用的实验研究

以一株质芽孢杆菌为例研究实验条件下微生物对磷矿石的风化作用.以直接作用和间接作用的方式研究培养基中胶质芽孢杆菌对磷矿粉的风化作用,即在装有100目磷矿石粉的液体培养基中接种,研究该菌对磷矿石粉的直接风化作用;同时,将装有100目磷矿石粉的透析袋放入液体培养基中再接入该菌,研究其对磷矿石粉的间接风化作用.按不同时间取培养液上清液,过滤,用电感耦合等离子体发射光谱(ICP-OES)测定滤液中Ca2 、Mg2 、Na 、Mn2 、Al3 、Fe3 和K 等浓度,比色法测定水溶性P(Pws)和水溶性Si (Siws) 的含量;滤膜上的固体物称重并消解后,同上方法测定Ca2 、Mg2 、Na 、Mn2 、Al3 、Fe3 和K 等浓度以及Pws和Siws含量.此外,细菌风化作用后的矿物残渣用电子探针作表面微观形态分析和XRD矿物物相分析.结果表明:胶质芽孢杆菌对磷矿石粉风化的直接作用强度大于间接作用;对不同矿物的风化强度不同,对粘土矿物的风化作用较明显.提出细菌对磷矿石的风化作用源自细菌生长导致的机械破坏作用、胞外分泌物的生化降解作用以及多种因素之间的协同作用.

THE ROLE OF A STRAIN OF Bacillus mucilaginosus ON WEATHERING OF PHOSPHORITE ROCK UNDER EXPERIMENTAL CONDITIONS

The authors have examined the microbiological weathering effect of phosphorite by using Bacillus mucilaginosus strain as an example under laboratorial conditions.In liquid culture,incubation in static state,the weathering of apatite with the bacteria was done by using the contrast method: apatite powder(100 mesh) was put in the liquid culture medium in a flask,the medium was autoclaved,followed by fungus inoculation for the study of direct weathering process;a dialysis bag with apatite powder(100 mesh) was put in the liquid culture medium in the flask,the medium was autoclaved,followed by bacteria inoculation so as to study the indirect weathering process.The supernatants collected at different incubation periods were determined in terms of the concentrations of Ca2 ,Mg2 ,Na ,Mn2 ,Al3 ,Fe3 and K by ICP-OES.The contents of water soluble phosphorus(Pws) and silicon(Siws) were determined by colorimetry in the filtrate.The solids were quantified and digested on the filter paper.The main cation concentrations and Pws,Siws in digest liquid were measured by the above method.The remaining minerals were micromorphologically analyzed by means of an electron microprobe,and the mineral composition was determined by XRD.The results showed that the direct weathering process was stronger than the indirect one.B.mucilaginosus had a capability of weathering toward phosphorite,and stronger ability to clay minerals.Based on our experimental results,it is concluded that the mechanical breakage of bacterial growth,the bio-degradation of extra cellular macromolecules,and the integrated operation of many factors seem to be the reasons for the bio-weathering of minerals.