Microbially-Active Functional Material Based Bioreactors for Continuous Production of Biofuels and Industrial Feedstock

拟议研究的更广泛的科学影响包括开发一种提高生物燃料生产效率的技术。生物能源和化学原料在利用可持续资源满足我们的能源和工业需求，同时最大限度地减少对环境的影响方面具有巨大的潜力。由于易于操作和控制，目前大多数工业过程使用间歇式生物反应器。开发一种成本效益高、反应动力学快、效率高、生产率高的连续流固定化微生物反应器是一个尚未满足的需求。稳定的连续流动生物反应器具有接近恒定的细胞密度，不需要频繁的接种和启动，并且允许持续生产感兴趣的代谢物，如生物乙醇。在实现这一目标的过程中需要克服的最复杂的问题，也是以前的尝试中没有克服的一个问题，是开发一种固定材料，在不阻碍微生物代谢途径的情况下保持固定微生物细胞的活力。在这种程度上，PI开发了一种新的美国专利正在申请中，以形成MAF材料，其中细胞活力和代谢途径都被保留。MAF材料是纤维内含有微生物的薄聚合物纤维支架，通过静电纺丝过程形成。这些薄的聚合纤维具有较高的营养物质和代谢物扩散率，使微生物能够存活。此外，纤维以完全随机的方式相互重叠，形成开放的孔结构，非常适合用于流动反应器。本提案旨在设计、开发、表征和评估一种以MAF材料为关键部件的IMBR。在IMBR中使用MAF材料将具有变革性。其核心假设是，这样一个系统将更有效率，生产率更高。除了设计和开发基于MAF材料的实验室规模IMBR之外，拟议研究的主要目标是：(i)评估和比较基于MAF材料的间歇发酵罐和IMBR的效率，（ii）确定IMBR中微生物的寿命和稳定性，以及（iii）优化MAF材料的特性，如孔隙率，纤维直径和IMBR流速，以提高IMBR的效率。PI最近通过静电纺丝工艺开发了MAF材料；这一工艺被广泛应用于聚合物纤维工业，因此很容易扩展到大规模的商业用途。

1159772ChidambaramThe broader scientific impacts of the proposed research involve developing a technology to increase the efficiency in biofuel production. Biologically generated energy and chemical feedstock hold immense potential in using sustainable resources to meet both our energy, as well as industrial needs, while minimizing environmental impacts. Most industrial processes currently use batch bioreactors due to ease of operation and control. There is an unmet need to develop a cost-effective continuous-flow, immobilized microbial bioreactor that has faster reaction kinetics, high efficiency and productivity. Stable continuous-flow bioreactors that have near constant cell densities do not require frequent inoculation and startup, and allows for consistent production of metabolites of interest, such as bioethanol. The most complex issue to be overcome in the pursuit of this goal, which is also the one issue that was not overcome in previous attempts, is to develop an immobilization material that maintains the viability of the immobilized microbial cells without hindering the metabolic pathways of the microbe. To this extent, the PI has developed a novel US Patent Pending immobilization process to form MAF materials in which both cell viability and metabolic pathways are preserved. MAF materials are thin polymeric fibrous scaffold containing microorganisms within the fibers and are formed via the process of electrospinning. These thin polymeric fibers have high rates of diffusion of nutrients and metabolites to allow microbial survival. Further, the fibers overlap each other in a completely random manner, giving rise to an open pore structure that is ideal for use in a flow reactor. This proposal aims to design, develop, characterize, and evaluate an IMBR in which the MAF material forms the key component. The use of MAF materials in an IMBR will be transformational. The central hypothesis is that such a system will be more efficient and have high productivity.The principal objectives of the proposed research, in addition to the design and development of MAF materials based laboratory-scale IMBRs, are to: (i) evaluate and compare the efficiencies of the MAF material-based batch fermentors and IMBRs, (ii) determine the longevity and stability of microbes in the IMBRs, and (iii) optimize the MAF material characteristics such as porosity, fiber diameter, and IMBR flow rate, to increase efficiency of IMBRs.The PI has recently developed the MAF materials via the process of electrospinning; a process that is widely used in the polymeric fiber industry and therefore makes it readily scalable for large-scale commercial use.