Analysis and develerent of micmenviroment in aerobic/anaerobic soils controlling microbial consortia for remediation

土壤是由固、液、气三相组成的非均质环境。在降解危险化学品的生物强化过程中引入土壤的微生物被认为只在环境有利的微环境中生长。到目前为止，人们一直认为土壤微生物的生长受土壤微场地结构的影响。然而，决定微生物在微区生长的因素和机制还不是很清楚。尤其是空间和物理微环境的影响还没有得到重视。本研究旨在探讨土壤微环境，尤其是土壤物理环境对微生物生长和群落结构的影响。通过呼吸苯二酚图谱分析、直接镜检法、16S RNA基因的PCR-DGGE分析等方法对微生物生物量和群落结构进行了测定。在好氧微生物中用脱氢酶测定微生物活性，在厌氧微生物中用多氯联苯脱氯活性测定微生物活性，评价土壤颗粒大小、含水率和土壤固结对好氧微生物生长和群落结构的影响。对颗粒大小和水分含量有显著影响。培养1个月后，微生物群落结构趋于稳定。以4个不同平均直径(0.01 mm~2 mm)的玻璃微珠为模型粒子，构成均匀的物理环境。在好氧微生物中，随着玻璃微珠直径的减小，微生物的生长程度降低，放线菌与变形杆菌的比例增大。在厌氧微生物中，虽然对多氯联苯的脱氯活性影响不大，但不同的玻璃微珠大小导致了不同的群落结构。

Soil is a heterogenous environment composed of solid, liquid and atmospheric phases. Microorganisms introduced into soil in the procedure of bioaugumentation for degrading hazardous chemicals are considered to grow only at the microsites with favorable environments. Until now, it has been believed that the growth of soil microorganisms are affected by soil structure of microsites. However, the factors and mechanisms determining the microbial growth at the microsites are not well understood. Especially, the effects of space and physical microenvironment has not been focused. In this project, we evaluate the effect of soil microenvironment, especially physical environment, on microbial growth and the community structure.Microbial biomass and community structure were measured by respiratory quinone profile analysis, direct microscopic method, PCR-DGGE analysis of 16S RNA genes. Microbial activity was measured by dehydrogenase in the case of aerobes and by PCB dechlorination activity in the case of anaerobes.We evaluated the effects of particle size, moisture content and consolidation of soils on the growth and community structure of aerobic microorganisms. Significant effects were observed in particle size and moisture content. Microbial community structure became stable after 1 month of incubation. As model particles, four glass beads with different average diameter (0.01mm to 2mm) were used to make a homogenous physical environment. In aerobic microorganisms, with the decrease of diameter of glass beads, the degree of growth decreased and the ratio of Actinobacteria to Proteobacteria increased. In anaerobic microorganisms, although PCB dechlorination activity was not affected significantly, the different glass beads size resulted in the different community structure.