The present work evaluated the influence of agitation and aeration on Escherichia coli growth and green fluorescent protein (GFP) production in conventional agitated tank bioreactors. The microorganism used was recombinant Escherichia coli BL21 DE3 pLysS pET28(a) and the culture medium was Luria-Bertani (LB) with lactose addition. For the quantification of GFP the samples were read in 96-well plates to determine the fluorescence unit (UF), using plate reader with 488 nm excitation wavelength and fluorescence emission of 507 nm. A previously established calibration curve was used for the conversion of UF to GFP concentration (mg/L). The experiments were carried out in a conventional agitated and aerated tank bioreactor, TEC-BIO-FLEX Tecnal-Brasil®, equipped with pH, temperature, dissolved oxygen, rotation, rotor for aeration and nutrient feed pumps, addition of antifoam and addition of acidic and basic solutions. The bioreactor has a total volume of 7.5 L and 5.0 L of useful volume. In the present work, 4 L of LB medium containing lactose at the concentration of 40 g/L were added to the reactor. Lactose acted as carbon source and inducing agent. For inoculation of the reactor, pre-inoculum was made in pure LB medium, maintained at 30oC, 150 rpm for period between 12-16h. The production phase was started with an optical density of 0.1. The antibiotics used were kanamycin and chloramphenicol at a concentration of 25 μg/mL. The tests were performed at 25oC, 0.5 vvm and only the stirring was varied: 400 rpm and 800 rpm. It was possible to observe increase in GFP production, however, there was no proportional increase in bacterial growth, a result evidenced by the Yp/x that did not remain constant in both conditions.

Evaluation of the influence of agitation and aeration on the production of green fluorescent protein (GFP) using recombinant Escherichia coli in conventional bioreactor

2019 Spring National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.