서강대학교

초록/요약

Lactic acid is one of popular organic acid because of its wide range of utility and applicability. Conventionally, lactic acid was mainly regarded as food additives or health care supplies. But in recent bio-industry, lactic acid is come into the spotlight because it can be used as intermediate to produce biodegradable polymer. Systems biotechnology technique is widely used for optimization of fermentation conditions and prediction of final product’s yield. For these reasons, dynamic model of lactic acid fermentation using Lactococcus lactis is constructed. Additionally, metabolic flux analysis (MFA) and metabolic control analysis (MCA) have done for intensive metabolic understanding of lactic acid bacteria. To construct kinetic model of lactic acid fermentation, metabolic kinetic parameters and enzyme concentrations are collected from BRENDA and other literatures. Kinetic parameters of metabolic pathway are attained from KEGG database and literatures. Parameter estimation has conducted with COPASI software for the purpose of construct more accurate metabolism model. Experimental used in parameter estimation was attained from LC-MS/MS analysis and time course simulation result. MFA results were reasonable explanation to experimental data. Through parameter estimation, metabolic system of lactic acid bacteria can be thoroughly understandable through comparison to original parameters. Coefficients derived from MCA, indicates that reaction rate of LDH is activated by fructose 1, 6-bisphosphate and pyruvate. And pyruvate appears to be stronger activator on LDH than fructose 1, 6-bisphosphate. Also, pyruvate acts as inhibitor to PK and PTS. Glucose 6-phosphoate and phosphoenolpyruvate shows activation effect on PK. PERM is the strongest effector on flux through LDH. Concentration control coefficient (CCC) shows similar result to flux control coefficient (FCC).