Track
Poster Abstract
Title
Dynamic Flux Balance Modeling of a Microbial Co-Culture for Efficient Batch Fermentation of Glucose and Xylose Mixtures
Subject Area
Biological Conversion
Abstract
A requirement for the economically viable production of fuels from cellulosic biomass is the efficient consumption and conversion of its constituent sugars. Genetically engineering a single organism to metabolize multiple sugars typically results in inefficiencies due to diauxic growth and/or limitations in substrate uptakes. We present a mathematical model of a synthetic consortium for the production of ethanol from mixtures of glucose and xylose. The co-culture is composed of wild-type Saccharomyces cerevisiae and Escherichia coli strain ZSC113, two microbes that will specifically uptake glucose and xylose, respectively. Dynamic flux balance analysis is employed to compare this co-culture to mono-cultures of individual S. cerevisiae and E. coli strains capable of consuming both sugars with respect to their batch ethanol productivities. The effects of altering the amount of each microbe present in reactor inoculum and changing the time at which the batch is switched from aerobic to anaerobic cultivation are investigated. Through these process engineering strategies, a nearly two-fold increase in ethanol productivity over pure cultures is predicted under the assumption of optimal growth conditions for each microbe. Future work will focus on verifying these results experimentally to test the limitations of this assumption and the assumption that the microbes are non-interacting.
Dynamic Flux Balance Modeling of a Microbial Co-Culture for Efficient Batch Fermentation of Glucose and Xylose Mixtures
A requirement for the economically viable production of fuels from cellulosic biomass is the efficient consumption and conversion of its constituent sugars. Genetically engineering a single organism to metabolize multiple sugars typically results in inefficiencies due to diauxic growth and/or limitations in substrate uptakes. We present a mathematical model of a synthetic consortium for the production of ethanol from mixtures of glucose and xylose. The co-culture is composed of wild-type Saccharomyces cerevisiae and Escherichia coli strain ZSC113, two microbes that will specifically uptake glucose and xylose, respectively. Dynamic flux balance analysis is employed to compare this co-culture to mono-cultures of individual S. cerevisiae and E. coli strains capable of consuming both sugars with respect to their batch ethanol productivities. The effects of altering the amount of each microbe present in reactor inoculum and changing the time at which the batch is switched from aerobic to anaerobic cultivation are investigated. Through these process engineering strategies, a nearly two-fold increase in ethanol productivity over pure cultures is predicted under the assumption of optimal growth conditions for each microbe. Future work will focus on verifying these results experimentally to test the limitations of this assumption and the assumption that the microbes are non-interacting.