Application of process system engineering tools to the fed-batch production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) from a vinasses–molasses Mixture

Real‐time optimization and control for polyhydroxybutyrate fed‐batch production at pilot plant scale

“…The differences obtained in the calculated feeding profiles influence the polymer obtained, not only in terms of polymer concentration but also in terms of thermo-mechanical properties. 31 The substrate control law applied, for most of the time, the highest feed flow rate in order to keep the substrate concentration at 23 g/L. On the other hand, the combined-oriented optimization applied a high feed flow rate during the first process stage (where X t (t) < X trh ), but then, during the second stage, the feeding policy changed and the feed flow rate was kept at low values.…”

“…Although the attained productivity (0.364 g/L h) is low, it is around 35% higher than previously reported values for PHA production from a similar vinasses-molasses mixture at 5 L-scale. 31 Furthermore, in a complete review, Blunt et al 44 mentioned that the highest volumetric PHA productivity reported in the open literature (using sucrose as substrate at 6.6 L scale) is 5.1 g/L h (reported by Wang and Lee 45 Since then, similar results have not been reported on a scale of more than 100 L. According to the authors in their review, it was found that more recently, fed-batch and cyclic (batch and fedbatch) bioreactor operation strategies have reported productivities of 1 g/L h to 2 g/ L h under more realistic conditions for pilot or industrial-scale production (i.e. including the utilization of lower-cost waste carbon substrates and atmospheric air as aeration medium).…”

“…Microorganism and culture conditions Vinasses used in this work were provided by INCAUCA S.A.S (Valle del Cauca, Colombia), which were pre-treated as described by García et al 31 Cupriavidus necator (C. necator) ATCC 17699 was cultured in Tryptic Soy Broth (TSB) and glycerol (30% wt. ), and preserved at a temperature of −20°C.…”

“…The polymer quantification protocol used, as well as FTIR analysis, is described in detail in a previous work. 31 Finally, Size Exclusion Chromatography (SEC) was used for determining the number average (Mn) and weight average (Mw) molecular masses of the biopolymer obtained. Chloroform was used as eluent, with a flow rate of 1 mL/min and temperature of 23°C.…”

“…The soft-sensor block was built based on a previous work, 31 where substrate concentration is predicted by using CO 2 measurements at the off-gas. The equation derived for the soft-sensor prediction is: 31…”