Optimisation of Operating Conditions in Fed-Batch Baker’s Yeast Fermentation

Abstract

TurkeySaccharamyces cerevisia known as baker's yeast is a product used in various food industries. Worldwide economic competition makes it a necessity that industrial processes be operated in optimum conditions, thus maximisation of biomass in production of saccharamyces cerevisia in fedbatch reactors has gained importance. The facts that the dynamic fermentation model must be considered as a constraint in the optimisation problem, and dynamics involved are complicated, make optimisation of fed-batch processes more difficult.In this work, the amount of biomass in the production of baker's yeast in fed-batch fermenters was intended to be maximised while minimising unwanted alcohol formation, by regulating substrate and air feed rates. This multiobjective problem has been tackled earlier only from the point of view of finding optimum substrate rate, but no account of air feed rate profiles has been provided. Control vector parameterisation approach was applied the original dynamic optimisation problem which was converted into a NLP problem. Then SQP was used for solving the dynamic optimisation problem. The results demonstrate that optimum substrate and air feeding profiles can be obtained by the proposed optimisation algorithm to achieve the two conflicting goals of maximising biomass and minimising alcohol formation.

Maximizing biomass concentration in baker’s yeast process by using a decoupled geometric controller for substrate and dissolved oxygen

“…Significant complexity arises in maintaining the biomass concentration along a desired trajectory while simultaneously holding the ethanol concentration below a certain value. The final biomass or ethanol concentration that is achieved varies with the operating conditions and the control schemes used (Atasoy et al, 2013;Valentinotti et al, 2003;Borowiak et al, 2012;Chuo et al, 2011;Yüzgeç et al, 2009;Hitit et al, 2014).…”

“…After crossing this stage, the central carbon flux is directed towards the production of ethanol and acetic acid, resulting in a decrease in the biomass production yield. Thus, biomass and ethanol are products formed in the extremes of metabolic regimes from yeast (Atasoy et al, 2013). Irrespective of the product at the end, the yeast fermentation process needs stringent regulation of critical process parameters to follow a particular metabolic regime.…”

Multiobjective Optimization for Enhanced Production of Therapeutic Proteins in Escherichia coli: Application of Real-Time Dielectric Spectroscopy

“…Product concentration and productivity of a biologic are significant for commercialization, and thus, optimization of the total biomass in a reactor plays a significant role. , Several researchers have attempted to apply various optimization objectives including biomass maximization and undesired product minimization, wherein different manipulated variables (MVs) like the substrate feed rate and air feed rate have been implemented. − Because the downstream operation accounts for a significant production cost for any biologic, achieving maximum biomass with a minimum reactor volume will be beneficial with respect to enhanced productivity and economics and thus could serve as an alternative for the generally developed cost-based objective functions if the total production cost is unknown. , Therefore, the combination of the two aforementioned conflicting objectives and achieving higher volumetric productivity of a biologic would be relevant in view of growing interest of continuous processing in the biopharmaceutical industry …”