Table 1. Main properties of bacterial IBs adjustable through process conditions.

 Parameter       IBs structure features                             Reference

                 When culture time after induction increased,
                                                                    (Margreiter, et al.,
                 IBs median diameter augmented. Also, as the
                                                                    2008, Upadhyay,
                 culture time passed, IBs showed strong binding
                                                                    et al., 2012,
 Culture time    with Congo red and Thioflavin-T (suggesting
                                                                    Castellanos-
                 more amyloid content), and they became
                                                                    Mendoza, et al.,
                 more resistant to proteolysis and
                                                                    2014)
                 denaturation.

               Low concentration of inductor (IPTG)                 (Luo, et al., 2006,
 Inductor      decreased the aggregation and hydrodynamic           Margreiter, et al.,
 concentration diameter. Some IBs increased in RP content           2008, Jhamb &
               under lower inductor concentration.                  Sahoo, 2012)

                 At low specific growth rates, less abundant IBs
                                                                    (Iafolla, et al.,
 Growth rate     were found. However, more RP was present in
                                                                    2008)
                 IBs formed at the fastest growth rate.

                                                                (Schein &
                 IBs formed at low temperature presented        Noteborn, 1988,
                 some properly folded and active proteins, less Strandberg &
                 impurities, and were solubilized and denatured Enfors, 1991,
 Temperature     faster than those formed at high temperature. Jevsevar, et al.,
                 Increase in temperature promoted RP            2005, de Groot &
                 aggregation and improved the IB production     Ventura, 2006,
                 rate.                                          Peternel, et al.,
                                                                2008)

                                                                    (Strandberg &
                 Relative amount of IBs increased with the
                                                                    Enfors, 1991,
                 decline in pH during culture. IBs formed under
                                                                    Castellanos-
 pH              basic pH, presented more -helices, were less
                                                                    Mendoza, et al.,
                 resistant to proteolysis and bonded less
                                                                    2014, Calcines-
                 Thioflavin-T, vs. IBs produced at acidic pH.
                                                                    Cruz, et al., 2018)

                 Diffused protein clusters were seen inside cells
                 cultured in shake flasks under acoustic
                 resonant mixing at high energy (20 g)              (Valdez-Cruz, et
 Agitation
                 compared with IBs formed under orbital             al., 2017)
                 agitation. IBs at 20 g were less resistant to
                 proteolysis.




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Human interferon–α2 (IFN–α2); interferon–γ (IFN–γ); Human growth hormone (hGH); Xylanase
(XynB); Alzheimer-related peptide Ab42 mutant fused to green fluorescent protein
(Ab42(F19D)-GFP); green fluorescent protein (GFP); protein A from Staphylococcus aureus and
I-galactosidase (SpA-gal); Isopropyl β-D-1-thiogalactopyranoside (IPTG); Not determined (N.D.);
guanidinium chloride. (GnCl); Thioflavin-T (Th-T); Recombinant protein (RP).




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