METABOLITE PROFILING OF CELLULOLYTIC MICROORGANISMS FOR BIOFUEL PRODUCTION

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 背景：对于已建立的以纤维素为基础的产氢共培养系统，已经在具有合养微生物的生物反应器中实现了适度的产氢。然而，人们对生物体之间的代谢相互作用知之甚少。这一缺陷阻碍了提高制氢效率的系统优化。 方法：以纤维素为原料，与溶纤维梭菌H10和沼泽红假单胞菌CGA584共培养制氢。H10的黑暗发酵将纤维素分解成小的有机酸、二氧化碳和氢气。CGA584不能直接利用纤维素或葡萄糖，但它可以进一步降解H10大量产生和释放的发酵产物，产生额外的H2。建立了稳定的共培养体系，并对合养生长的动力学和化学计量进行了监测。我们已经确定了H10产生和释放的几种有机酸，但重要的是确定其他以前未确定的代谢物是否由H10释放，从而可供CGA584吸收和代谢。因此，我们建议使用AMS来确定H10释放的其他代谢物的存在或不存在，这些代谢物是使用带有UV-Vis和折射率检测的高效液相无法检测到的。 这些实验结果将为进一步表征H10和CGA584在以纤维素为原料生产氢气作为生物燃料过程中的代谢相互作用提供基础。 预期结果和未来方向：我们预计我们能够确定之前未确定的代谢物是否由H10分泌，这将使我们能够开发方法来识别这些代谢物并在未来的实验中监测它们。这些实验还将证实，H10分泌的代谢物是CGA584的唯一碳源。这些信息，以及它将实现的其他实验的数据，将为计算模拟由于纤维素降解而产生的氢燃料生产中H10和CGA584之间的相互作用提供基础。然后，可以使用有效的计算模型来预测生物燃料生产的最佳增长条件。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Background: For established cellulose-based H2-producing co-culture systems, modest H2 production has been achieved in bioreactors with syntrophic microorganisms. However, the metabolic interactions between the organisms are poorly understood. This shortcoming hinders system optimization for improving H2 production efficiency. Methods: We achieved a co-culture system for H2 production based on cellulosic materials with Clostridium cellulolyticum H10 and Rhodopseudomonas palustris CGA584. Dark fermentation by H10 decomposes cellulose into small organic acids, CO2 and H2. CGA584 cannot use cellulose or glucose directly, though it can further degrade fermentation products produced and released in large quantities by H10, yielding additional H2. A stable co-culture was established and the kinetics and stoichiometry of the syntrophic growth were monitored. We have identified several of the organic acids produced and released by H10, but it is important to determine whether other, previously unidentified metabolites are released by H10 and thus become available for uptake and metabolism by CGA584. Therefore, we propose to use AMS to determine the presence or absence of additional metabolites released by H10 that are not detectable using HPLC with UV-Vis and refractive index detection. Results from these experiments will provide the basis for further characterization of the metabolic interaction between H10 and CGA584 in the production of H2 as a biofuel using cellulose as a feedstock. Expected Results and Future Directions: We anticipate that we be able to determine whether previously unidentified metabolites are secreted by H10, which will allow us to develop methods to identify those metabolites and monitor them in future experiments. These experiments will also confirm that metabolites secreted by H10 are the sole carbon source for CGA584. This information, and data from the additional experiments it will enable, will provide a basis for computational modeling of the interaction between H10 and CGA584 in the production of H2 fuel as a result of cellulose degradation. A valid computational model can then be used to predict optimal growth conditions for biofuel production.