Strategies for Enhancing Product Yield: Design of Experiments (DOE) for Escherichia coli Cultivation

Abstract

E. coli is considered one of the best model organism for biopharmaceutical production by fermentation. Its utility in process development is employed to develop various vaccines, metabolites, biofuels, antibiotics and synthetic molecules in large amounts based on the amount of yield in shake flasks, bioreactors utilised by batch, fed-batch and continuous mode. Production of the desired molecule is facilitated in the bioreactor by employing strategies to increase biomass and optimised yield. The fermentation is a controlled process utilising media buffers, micronutrients and macronutrients, which is not available in a shake flask. To maximise the production temperature, dissolved oxygen (aerobic), dissolved nitrogen (anaerobic), inducer concentration, feed or supplementation of nutrients is the key to achieving exponential growth rate and biomass. Design of experiments (DOE) is critical for attaining maximum gain, in cost-effective manner. DOE comprises of several strategies likewise Plakett-Burman., Box–Behnken, Artificial Neural Network, combination of these strategies leads to reduction of cost of production by 2–8 times depending on molecules to be produced. Further minimising downstream process for quickly isolation, purification and enrichment of the final product.

Controlling Substrate- and Stereospecificity of Condensation Domains in Nonribosomal Peptide Synthetases

“…To this end, plasmids harboring the DNA fragment grsA*-grsB or mutants thereof were generated and independently introduced into the heterologous expression host HM0079. Instead of changing one cultivation factor at a time, Design of Experiment (DOE) , was employed to optimize the cultivation conditions, which were applied in all subsequent experiments (Supporting Information “Experimental Procedures”, Table S4 and Figure S8). Five single colonies of each HM0079 strain carrying grsA* and grsB, grsB-F155I, grsB-N256A, or grsB-E386L were cultivated in parallel, and pentapeptides were extracted from the cultures after 48 h. With mutations F155I and N256A, only d -form peptides were detected and the percentage of vPVOL increased from 9% (HM0079/grsA*-grsB) to 30% and 40%, respectively (Figure C).…”