Kinetic studies on the expression of alginate and extracellular proteins by <i>Pseudomonas aeruginosa</i> FRD1 and PAO1

Abstract

Pseudomonas aeruginosa is characterized by its capability to produce extracellular virulence proteins and to establish biofilm-based infections that do not respond easily to conventional treatments. However, the physiological conditions that decrease the fitness of such a persistent pathogen would assist the host to defend itself and reduce the infection prevalence. Therefore, developing treatments against P. aeruginosa requires a quantitative understanding of the relationship between bacterial growth kinetics and secretion of alginate and proteins, in addition to the ecological factors that control their synthesis. For this purpose, we examined various environmental factors that affect the specific product yield coefficients (expressed as g product/OD 600) of alginate and extracellular proteins using a mucoid (FRD1) and a non-mucoid (PAO1) clinical isolate of P. aeruginosa, respectively. The results suggested magnesium sulfate, trace elements and hydrogen peroxide as significant variables that positively affect alginate synthesis by the FRD1 cells. However, the production of extracellular proteins by PAO1 was negatively affected by the concentration of ferrous sulfate. For understanding the kinetics of expressing alginate and extracellular proteins by the cells, a well-controlled 5 L tank bioreactor was used. The results suggested that under the bioreactor controlled conditions, both alginate and extracellular proteins are expressed parallel to biomass increase in the cells of P. aeruginosa.

Biosynthesis of Silver Nanoparticles by Aspergillus terreus: Characterization, Optimization, and Biological Activities

“…Design of experiments (DOE) such as fractional factorial designs are sets of statistical and mathematical tools used for analysis and modeling of the processes where the response is influenced by several variables (Lotfy et al, 2018a). DOE are generally used to identify the most significant parameters in the bioprocess and to predict the optimal conditions (El-Helow et al, 2019;Lotfy et al, 2019). DOE are more effective, reliable and consume less materials, time, and effort to determine the near optimum settings for each variable.…”

Hyaluronic acid production by Klebsiella pneumoniae strain H15 (OP354286) under different fermentation conditions

“…Adopting statistical optimization methods like fractional factorial design and response surface methodology could be beneficial. These techniques, as showcased in studies by Lotfy [ 64 ], Walid [ 65 ], and El-Helow [ 66 ], can better elucidate the intricate interplays between variables, offering a more rounded perspective on the subject. 2.…”

Improved production of Bacillus subtilis cholesterol oxidase by optimization of process parameters using response surface methodology

“…FFD and RSM have been applied in several biotechnological applications [23][24][25][26][27][28] as they provide quick screening and evaluation of the optimal levels of variables. In the current work, according to the Plackett-Burman experiment, cholesterol concentration (g/l), inoculum size (%), and magnesium sulphate (g/l) were the most significant factors affecting cholesterol degradation (%) by B. subtilis.…”

“…Screening and predicting the levels of optimal variables using a mathematical model through fractional factorial design (FFD) and response surface methodology (RSM) have been reported in various biotechnological applications [23][24][25][26][27][28]; however, these techniques have not been applied to the synthesis of cholesterol oxidase by B. subtilis. In the present work, FFD and RSM were implemented to enhance the cholesterol oxidase synthesis by B. subtilis.…”