非光合微生物菌群好氧固定CO_2的研究

CO_2 fixation with non-photosynthetic microbial flora under aerobic condition

微生物固定CO_2在环境、资源方面具有重要意义。然而,通常具有较高固碳能力的光合细菌和氢-氧化细菌由于需要光照/严格厌氧和供氢,限制了其在反应器或土壤中的应用。本研究通过生物技术手段从海水及其沉积物中选育到在普通好氧条件下具有固碳能力的非光合微生物菌群,并通过电子供体和无机碳源结构的优化,显著提高了其对无机碳的同化能力,好氧条件下固碳菌液的最高无机碳同化效率可达110 mgCO_2/L·d,为实现普通环境条件下的微生物固碳奠定了基础。同时,通过分子生物学手段研究了不同环境条件下固碳微生物菌群的群落结构,以期为进一步优化固碳微生物群落结构,提升固碳效率提供理论依据。结果发现在不同培养条件下,菌群的群落结构发生了很大改变,表明不同条件下的固碳优势菌属于不同的种属,但通过测序、序列比对及构建系统发育树后发现,在已测序的16个显著条带中,11个是不可培养微生物,即其只能以共生方式存在,混合培养时,固定CO_2的效果可能是多种菌共同作用的结果。这意味着单一纯种微生物的固碳效率可能较低,研究与优化固碳微生物菌群的结构和配比将有利于固碳效率的提升。

CO2 fixation with microorganisms is of great significance in the environment and resources. However, the need for light and hydrogen restricts the application of photosynthetic bacteria and hydrogen-oxidizing bacteria with high efficiency of CO2 fixation capacity in reactors and soil. In this experiment, the non-photosynthetic microbial flora, which could fix CO2 under aerobic conditions, were obtained from seawater and sediments. The assimilation ability of the mixed microbial flora, to inorganic carbon was improved significantly through the optimization of the electron donor and the structure of inorganic carbon resource. The maximum assimilation efficiency of inorganic carbon of the mixed culture under aerobic conditions was 110 nag CO2/L·d. To further optimize the community structure of carbon fixation microorganisms for improving carbon fixation capacity, the community structure of inorganic carbon fixation microorganisms under different culture conditions was studied through molecular biological technology. It showed that the microbial community structure of various culture conditions was different obviously. Therefore, predominant microorganism.s of carbon fixation belong to different species. Through DNA sequence analysis, alignment and building phylogenetic tree, it was found that 11 species of 16 predominant species in the microbial flora was uncultured. This means that the carbon fixation efficiency of single microorganism may be lower, and the inorganic carbon fixation effect of the microbial flora may be the results of co-function of multi-microbial species. So that the efficiency of inorganic carbon fixation can be enhanced further through studying and optimizing microorganism structure and their match.