微小杆菌Exiguobacterium spp.及其环境应用研究进展

Exiguobacterium spp. and Their Applications in Environmental Remediation

微小杆菌属(Exiguobacterium spp.,简称E.spp.)是一类革兰氏阳性、无芽孢、兼性厌氧菌.其生境广阔,广泛分布于西伯利亚永冻土、海底热液口、植物根际等环境,多数菌种具有耐/嗜热性、耐/嗜冷性、耐/嗜碱性、耐/嗜盐性,蕴藏着丰富的微生物资源,亟待发掘.本文总结了目前已知的E.spp.14个菌种,发现其在进化树上分成两簇,分簇结果与菌株的温度耐受性对应,并且在氧化酶活性、硝酸盐还原能力等方面也存在着明显的簇间差异.进一步对这些差异进行机理探讨,并对E.spp.嗜极性及其在环境生物修复中的应用研究进行了归纳,探讨了E.spp.在分解有机污染物(偶氮染料、农药、石油等),转化重金属,根际促生,工业污水处理等领域的环境学意义.最后对E.spp.及其活性物质在环境修复、工农业生产发展中的应用提出展望,指出环境基因组学研究和工程菌的建立将极大拓展此类菌的资源化和实际应用.

Bacteria of the genus Exiguobacterium are Gram-positive, non-spore-forming, and facultatively anaerobic, largely unknown even though they are environmentally robust and versatile. Exiguobacterium spp. has been isolated from markedly diverse sources, including Siberian permafrost, deep-sea hydrothermal vents and the rhizosphere of plants. Many Exiguobacterium spp. are psychrophilic or thermophilic, alkalophilic or halophilic. This paper discussed the characteristics of the 14 known Exiguobacterium spp. in detail, including both physiological and biochemical properties. They are divided phylogenetically into two groups, which seem to correspond to different preferences in growth temperature, as well as differences with respect to oxidases and nitrate reduction. We then summarized the applications of Exiguobacterium spp. in environmental bioremediation of a wide range of pollutants, such as organic matters （including azo dyes, pesticides, petroleum, etc）, heavy metals, industrial wastewaters, as well as their role in promoting plant growth. The development of Exiguobacterium spp. and their active substances in environment remediation, agricultural and industrial productions were proposed. We believed that environmental genomics studies will help greatly in screening and establishment of engineered Exiguobacterium spp. strains for environmental applications. Fig 1, Tab 2, Ref 56