生物矿化在重金属污染治理领域的研究进展

Research Progress of Biomineralization in the Treatment of Heavy Metal Contamination

生物矿化通过生物代谢影响金属及类金属物质的形态分布,进而改变金属及类金属物质的生物有效性及毒性,在环境污染治理领域成为研究热点.文献计量学结果显示,2007—2017年生物矿化研究以微生物为主要对象,在纳米颗粒物和矿区修复等方面形成热点,并在环境学、生物学、化学和工程学等领域形成交叉学科.结合典型矿化菌与重金属间的矿化关联规律和微界面反应对微生物矿化中重金属的钝化机制进行归纳:(1)依据矿化菌与矿化产物的关联性对矿化菌进行分类,从碳酸盐、铁锰氧化物、硫化物和磷酸盐4类矿化产物角度汇总了碳酸盐矿化菌、铁锰氧化菌、硫酸盐还原菌及磷酸盐溶解菌的代表微生物;(2)矿化菌通过诱导矿化的方式固定重金属离子,其中碳酸盐矿化菌、硫酸盐还原菌及磷酸盐溶解菌可以直接促进金属矿物的形成,铁锰氧化菌生成的矿物间接吸附金属离子;(3)微生物矿化是由外及内的过程,细胞壁及胞外多聚物具有丰富基团,在矿化初期提供吸附和成核位点,原生质体也可以提供矿化场所,在矿化中后期继续固定游离离子.但是,由于微生物复杂的细胞结构及独特的生理习性,矿化过程的微界面反应机制研究尚显不足,需要利用生物学、矿物学、环境科学等领域的先进技术进一步的探索;同时也应开展宏观生态水平的生物矿化研究,并结合实际问题完善生物矿化在环境污染治理中的理论,为重金属污染地区的治理提供新的思路和技术.

Biomineralization can affect the species and mobility of metals by microbial metabolism processes,thereby influencing their toxicity and bioavailability,therefore can be utilized to treat environmental contaminated by metals and biomineralization have become a hotspot. Bibliometrics showed that microbe was the main object of biomineralization study,research in formation of nanoparticles and remediation of mining areas have become hotspots in the field of biomineralization from 2007 to 2017,and formed an interdiscipline based on environmental ecology,applied biology,chemistry and engineering. The passivation mechanism of heavy metals in biomineralization has been induced by summaries of mineralization links between typical mineralizing bacteria and heavy metals and summaries of microinterface reaction in biomineralization：（ 1） Classifications of mineralization bacteria have been done according to biomineral types,and summaries of representative microorganisms including carbonate mineralization microorganisms（ CMM）, Fe/Mn oxidizing microorganisms（ Fe/Mn OM）,sulfate reducing bacteria（ SRB）,phosphate solubilizing microorganisms（ PSM） have been finished according to four mineral types, such as carbonate, Fe/Mn oxide, sulfide, phosphate.（ 2） Metal ions were immobilized by biologically induced mineralization,microorganisms including CMM,SRB and PSM could directly promote the formation of metal minerals,and production ofFe/Mn OM could adsorb metal ions and become co-precipitation.（ 3） Microbial mineralization was a process from outside to inside. Cell walls and extracellular polymeric substances have abundant function groups,which provide sites for adsorption and nucleation at the beginning of mineralization,protoplasts can also provide mineralized sites,the immobilization of metal ions continued in the middle and late stages of mineralization. However,due to complex cellular structure and unique physiological habits of microorganisms,the study of microinterface reaction mechanism of biomineralization is still insufficient. Further exploration about this is needed by using advanced technologies in biology,mineralogy,environmental science,etc. Meanwhile,the study of biological mineralization at the ecological level should be carried out,and the theory of biomineralization in environmental pollution treatment should be augmented in combination with practical problems,all of these could provide new ideas and techniques for the treatment of heavy metal polluted areas.