Fig. 2
From: Revisiting Escherichia coli as microbial factory for enhanced production of human serum albumin
Effect of process parameters on the solubility of rHSA: densitometric analysis. a 12% SDS PAGE showing the change in the level of folding of rHSA subjected under different process conditions (A-L). Gel images (1–3; process conditions A–F) and (4–6; Process conditions G–L) represents the level of folding of rHSA under reducing and oxidizing intracellular environment respectively when induced via IPTG based (I) or AI and subjected to different post induction temperature. Lane UI represents uninduced cells; Lane I, induced cells; Lane SI, supernatant IPTG induced; PI, pellet IPTG induced; SAI, supernatant autoinduced; PAI, pellet autoinduced; Lane M, medium range protein molecular weight marker; Lane BSA, BSA Standard. b Graph shows the percentage of the soluble fraction of rHSA when expressed in E. coli cells subjected to different process parameters (A–L)—comprising intracellular environment, post induction temperature, and induction type- as obtained through their respective band intensities in the gel. The solubility of the rHSA has been depicted as the percentage of the rHSA obtained in the soluble fraction of the total expressed rHSA in the E. coli host system by carrying out densitometric analysis. Error bars represent standard error of the mean (SEM) with mean having 95% confidence limit. c Graph shows HSA activity units obtained when expressed in E. coli cells subjected to different process parameters (A–L) comprising intracellular environment (Rosetta DE3 or Origami2 DE3 E. coli cells), post induction temperature (18, 25, 37 °C) and induction type (IPTG or AI). Each bar represents the activity units of rHSA obtained when the normalized soluble fraction of the cell lysate, subjected to the respective condition, is analyzed for the activity assay. Rosetta only and Origami only bar represents the untransformed cells of E. coli strains and thus the control conditions. Here one unit of enzyme activity corresponds to one nanomole of pNP produced from pNPA per minute. Enzymatic activity expressed in the units of-nanomoles of pNP released/min/g dry cell weight. Error bars represent standard error of the mean (SEM) with mean having 95% confidence limit