Enhancing thermo-induced recombinant protein production in Escherichia coli by temperature oscillations and post-induction nutrient feeding strategies

Hydroxycinnamic acids and curcumin production in engineered Escherichia coli using heat shock promoters

“…For example, thermal induction can alter the protein folding of the recombinant proteins favoring protein aggregation into inclusion bodies [24,40]. Slower heating rates or the overexpression of a negative feedback deficient heatshock response transcription factor ( 32 ) would possibly prevent this problem in the production of heterologous proteins [28,40,41]. To evaluate the effect of the heat shock or the elevated TIR value in the expression of TAL, protein gel showing the proteins present in the soluble and insoluble fractions of cell-free extracts were performed ( Fig.…”

“…In some cases, protein production at 40-42 • C [24] also proved to be very efficient. Also, oscillatory induction should be considered since it has shown to be more effective, as it leads to longer productive times that result in higher titers [28]. In addition, this strategy reduces the drawbacks associated with the use of high temperature, such as formation of inclusion bodies, acetate overproduction, decreased growth rate, plasmid instability, proteolytic susceptibility and metabolic stress caused by heterologous protein production and heat shock [22,47].…”

“…Constitutive promoters or promoters induced by starvation of an essential nutrient, or by shift in a physical or physicochemical factor, such as temperature or pH, allow an inducer-free environment for heterologous protein expression [23]. Thermal induction in E. coli is carried out by increasing the temperature (usually 37 • C) to 42 • C or higher for a certain period and then, shifting it down [24][25][26][27][28][29][30][31]. A thermal induction strategy has the potential of reducing the fermentation cost since expensive chemicals or special media are not required.…”

Potential Applications of the Escherichia coli Heat Shock Response in Synthetic Biology

“…The heat transfer limitations of bioreactors should be considered, but slow heating rates such those often observed in large-scale bioreactors may favor heterologous protein production [69]. Fast heating rates generate a large imbalance between tricarboxylic acid cycle and glycolysis, leading to high energy requirements for overcoming the physiological stress [69,70]. In addition, HS promoters can help to reduce inclusion body formation and proteolytic degradation of more complex proteins because they are in general weaker promoters, and therefore the synthesis rate of the recombinant protein is reduced, allowing proper folding.…”

Process optimization of high-level extracellular production of alkaline pectate lyase in recombinant Escherichia coli BL21 (DE3)

“…However, if exponential feeding is applied in the full-course of fed-batch phase, the cultivations often leads to overproduction of acetate because the cells suffer from dissolved oxygen (DO) limitation. Therefore, to address this, in the present study, a multi-step feeding strategy based on cell growth and nutritional requirements was developed, which has been previously employed to achieve HCDC of E. coli [15,23]. In addition, appropriate induction and feeding strategies were established by examining major influential factors (e.g.…”