大腸桿菌在無氧環境下利用甘油生產酒精的模擬與分析

Abstract

世界能源危機的意識，使得利用微生物生產生質燃料如生質酒精、生質柴油等，已被廣泛的研究。雖然過去的研究主要探討以微生物分解纖維素的議題，纖維素降解程序仍然困難且繁鎖。相對地，甘油的化學結構簡單且能夠直接利用，而生質柴油生產的過程會產生大量的甘油。因此甘油成為生產生質燃料的理想材料。也因此，甘油厭氧利用的機制對於有效生成生質燃料與生物質有一定的重要性。 數學模擬應用於生物系統已有顯著的進展，這些模擬系統包含決定代謝反應的流量、預測基因調節作用以及對於細胞行為的解讀。雙相(two-phase)研究運用基礎流量模式(Elementary Flux Modes, EFMs)與非線性程式(nonlinear programming)分析並模擬大腸桿菌內甘油代謝之厭氧路徑。我們的分析能夠解釋並提供細菌於甘油厭氧代謝時，其生長問題的解決之道。此外，結合酵素動力準則與基礎流量模式能夠預測流量分布與代謝濃度，甚至作為基因剔除之參考。 這些資訊有助於代謝工程在基因層次之修飾並藉以提高目標物產量。

Using microbes as the machine to produce biofuel such as bioethanol and biodiesel have been widely investigated due to global energy crisis. While considerable attention has been paid in the past on issues related to decompose the cellulose by microbes, the procedure of cellulose degradation remains heavy and complicate. In contrast, the chemical structure of glycerol is simpler and can be used directly. Thus glycerol became an ideal substrate for biofuel generation because a mass of glycerol produced from biodiesel factory. Therefore, mechanism of glycerol anaerobic utilization is important for efficiently biofuel synthesis and biomass growth. Mathematical modeling for biology systems have progressed tremendously, including determination of metabolic fluxes, prediction of gene regulations, and interpretation of cell behaviors. A two-phase study was designed to utilizing elementary flux modes (EFMs) and nonlinear programming for analysis and modeling glycerol metabolic anaerobic pathway in Escherichia coli. Our analysis explains and provides solution for the growth problem of bacteria during glycerol anaerobic metabolism. Besides, the model combining enzyme kinetic principle and elementary flux modes (EFMs) could predict the flux distribution and concentration of metabolites even gene deletion, which helps metabolic engineering to modify gene for product optimization.