Mass transfer in bioreactors and reactors

这项研究计划的目的是了解从几纳米到几微米的分子长度尺度的化学反应和扩散之间的耦合作用。这项研究将调查与能源和环境有关的两个重要反应；油砂沥青的热裂解，以及细菌将碳氢化合物输送到细胞内和产甲烷联合体细菌之间。在高温裂解和烃类生物转化过程中，反应分子的短距离运动都对反应有深刻的影响。例如，当油砂沥青中的大分子在高温下破裂时，我们希望破裂的碎片逸出到气相中，释放出有价值的产品。如果破碎的碎片不能足够快地扩散出液相，那么它们就会发生反应，形成低价值的焦炭。在细菌转化碳氢化合物的过程中，细胞壁在决定哪些化合物进入细胞中起着关键作用。细胞壁内的蛋白质泵可以将抗生素和碳氢化合物等化合物从细胞中移除。了解和控制化合物在细胞壁上的运动是利用细菌作为有效的生物反应器进行环境净化和将碳氢化合物转化为有用产品的关键一步。

The objective of this research program is to understand the role of coupling between chemical reactions and diffusion of molecules length scales from a few nanometers to a few microns. The research will investigate two important reactions relevant to energy and the environment; thermal cracking of oil sands bitumen, and the bacterial transport of hydrocarbons into cells and between bacteria in methanogenic consortia. In both high-temperature cracking and in biological conversion of hydrocarbons, the reactions are profoundly affected by the movements of the reacting molecules over short distances. For example, when large molecules in oil sands bitumen break apart at high temperature, we want the cracked fragments to escape to the vapor phase to release valuable products. If the cracked fragments cannot diffuse out of the liquid phase fast enough, then they can react to form low-value coke instead. In bacterial conversion of hydrocarbons, the cell wall plays the key role in determining which compounds enter the cell. Protein pumps within the cell wall can remove compounds such as antibiotics and hydrocarbons from the cell. Understanding and controlling the movement of compounds across the cell wall is a crucial step to using bacteria as effective bioreactors for environmental cleanup and for conversion of hydrocarbons to useful products.