Evolutionary Engineering Applications in Microbial Ethanol Production - Abstract
Microbial biofuel production using renewable resources is an important alternative to conventional petroleum-based fuels. In this respect, conversion of the cellulosic biomass as the renewable resource to simple sugars and biofuels is the main strategy. Among a variety of biofuel types, ethanol is a widely studied biofuel, and ethanol production from lignocellulosic biomass is a major field of research. For efficient ethanol production, improvements in both the producer microorganism and the process are required. Most of the research for the improvement of the microorganism focuses on sugar utilization, tolerance to inhibitor stresses that occur during ethanol production, and tolerance to ethanol as the product. As all of these properties are genetically complex (multigenic) properties, evolutionary engineering, based on random mutation and systematic selection of desired phenotypes without the need for prior genetic or biochemical information about the basis of the desired phenotype, is a powerful and practical strategy to obtain these desired phenotypes. In this review, evolutionary engineering applications of microbial ethanol production are discussed, regarding sugar utilization, inhibitor and ethanol stress tolerance.