Year: 2024
Type: article
Abstract: Microorganisms in large-scale bioreactors are exposed to heterogeneous environmental conditions due to physical mixing constraints. Nutritional gradients can lead to transient expression of energetically wasteful stress responses and as a result, can reduce the titres, rates and yields of a bioprocess at larger scales. To what extent these process parameters are impacted is often unknown and therefore bioprocess scale-up comes with major risk. Designing platform strains to account for these intermittent stresses before introducing synthesis pathways is one strategy for de-risking bioprocess development. For example, Escherichia coli strain RM214 is a derivative of wild-type MG1655 that has had several genes and whole operons removed from its genome based on their metabolic cost. In this study, we engineered E. coli strain RM214 (referred to as WG02) to produce octanoic acid from glycerol in batch-flask and fed-batch bioreactor cultivations and compared it to an octanoic acid-producing E. coli MG1655 (WG01). In batch flask cultivations, the two strains performed similarly. However, in carbon limited fed-batch bioreactor cultivations, WG02 provided a greater than 22% boost to biomass compared to WG01 while maintaining similar titres of octanoic acid. Reducing the biomass accumulation of WG02 with nitrogen limited fed-batch cultivation resulted in a 16% improvement in octanoic acid titre over WG01. Finally, in a scale-down system consisting of a stirred tank reactor (representing a well-mixed zone) and plug flow reactor (representing an intermittent carbon starvation zone), WG02 again improved octanoic acid titre by almost 18% while maintaining similar biomass concentrations as WG01.
Source: Microbial Biotechnology
Institutions: University of Wisconsin–Madison, University of Stuttgart
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $3,700
Awards: G1953973806, G3540844361, THIS COOPERATIVE AGREEMENT IS AWARDED TO THE UNIVERSITY OF WISCONSIN FOR A PROJECT ENTITLED, ''ACETATE AS A
PLATFORM FOR CARBON-NEGATIVE PRODUCTION OF RENEWABLE FUELS AND CHEMICALS'' IN ACCORDANCE WITH FOA NUMBER
DE-FOA-0002387 (ECOSYNBIO) AND CONTROL NUMBER 2387-1511.
THROUGH AN ACADEMIC-INDUSTRIAL COLLABORATION, THIS PROJECT WILL DEVELOP A PARTITIONED MIXOTROPHIC PROCESS FOR
CONVERTING CO2 AND H2 TO REDUCED CHEMICAL PRODUCTS INCLUDING MEDIUM CHAIN FATTY ALCOHOLS AND TRITERPENOIDS, G5620962805, G6119448328
OpenAlex ID: W4404153625