Model-Based Optimization of a Fed-Batch Bioreactor for Mab Production Using a Hybridoma Cell Culture
Total Page:16
File Type:pdf, Size:1020Kb
molecules Article Model-Based Optimization of a Fed-Batch Bioreactor for mAb Production Using a Hybridoma Cell Culture Gheorghe Maria 1,2 1 Department of Chemical and Biochemical Engineering, University Politehnica of Bucharest, Polizu Str. 1-7, P.O. 35-107, 011061 Bucharest, Romania; [email protected]; Tel.: +40-744-830-308 2 Romanian Academy, Calea Victoriei, 125, 010071 Bucharest, Romania Academic Editors: Si Amar Dahoumane and Diego Ettore Liberati Received: 28 September 2020; Accepted: 26 November 2020; Published: 30 November 2020 Abstract: Production of monoclonal antibodies (mAbs) is a well-known method used to synthesize a large number of identical antibodies, which are molecules of huge importance in medicine. Due to such reasons, intense efforts have been invested to maximize the mAbs production in bioreactors with hybridoma cell cultures. However, the optimal control of such sensitive bioreactors is an engineering problem difficult to solve due to the large number of state-variables with highly nonlinear dynamics, which often translates into a non-convex optimization problem that involves a significant number of decision (control) variables. Based on an adequate kinetic model adopted from the literature, this paper focuses on developing an in-silico (model-based, offline) numerical analysis of a fed-batch bioreactor (FBR) with an immobilized hybridoma culture to determine its optimal feeding policy by considering a small number of control variables, thus ensuring maximization of mAbs production. The obtained time stepwise optimal feeding policies of FBR were proven to obtain better performances than those of simple batch operation (BR) for all the verified alternatives in terms of raw material consumption and mAbs productivity. Several elements of novelty (i–iv) are pointed out in the “conclusions” section (e.g., considering the continuously added biomass as a control variable during FBR). Keywords: monoclonal antibodies (mAbs) maximization; hybridoma cell culture; fed-batch bioreactor dynamics optimization; raw material consumption; time stepwise operating policy 1. Introduction Over the last decades, there has been a continuous trend in developing increasing numbers of effective cell or enzymatic reactors [1] to industrialize various biosynthesis technologies for producing industrial fine chemicals (including the bio-mimetic emulations, eventually by using Systems Biology tools, among others [2,3]) by using free-suspended or immobilized cell cultures/enzymes [4]. Effective and selective biosyntheses replaced energetically intensive chemical processes [5,6]. Bioreactors with microbial/animal cell cultures used for the production of a lot of products have been developed in simple constructive/operating alternatives as reviewed in Table1 together with some examples. Complex alternatives are extensively discussed by [7,8]. In spite of their larger volumes, continuously mixing aerated tank reactors, operated in BR (batch), or FBR (semi-batch) modes, are preferred for processes requiring high oxygen transfers, and rigorous temperature/pH control, as the case of the approached mAbs production. Molecules 2020, 25, 5648; doi:10.3390/molecules25235648 www.mdpi.com/journal/molecules Molecules 2020, 25, x FOR PEER REVIEW 2 of 26 Table 1. The main constructive and operating alternatives of bioreactors [1,4,5]. Molecules 2020, 25, x FOR PEER REVIEW 2 of 26 MoleculesReactor 2020 Type, 25, x FOR PEERNotation REVIEW [Examples] Operation; Modeling Hypotheses 2 of 26 Molecules 2020, 25,Table x FOR 1.PEER The REVIEW main constructive and operating alternatives of bioreactors [1,4,5]. 2 of 26 Molecules 2020, 25,Table x FOR 1.PEER The REVIEW main constructive and operatingisothermal, alternatives iso-pH, of bioreactors and iso-DO [1,4,5]. (air sparger);2 of 26 Reactor Type Notation [Examples] Operation; Modeling Hypotheses MoleculesMolecules2020 2020, 25, 25, 5648,Table x FOR 1.PEER(i) The simple REVIEW main Bconstructiveatch Reactor and operatingperfectly alternatives mixed of bioreactors liquid phase [1,4,5]. (with no 22 of of 25 26 Reactor Type Notation [Examples] Operation; Modeling Hypotheses Table 1. The main( constructiveBR) and operatingconcentration alternatives gradients, of bioreactors by using [1,4,5]. mechanical Reactor Type Notation [Examples] isothermal,Operation; iso-pH, Modeling and iso-DO Hypotheses (air sparger); Table 1. The main constructive and operating alternatives of bioreactors [1,4,5]. Reactor TypeTable 1. (i)TheNotation simpleExamples: mainconstructive B [Examples]atch [9,10] Reactor and operatingisothermal,agitation). alternativesperfectlyOperation; iso-pH,Reactants/biomass mixed of bioreactorsModeling liquidand iso-DO phase [Hypotheses1,4, 5added ].(air (with sparger); atno the Reactor Type (i)Notation simple (BBR [Examples]atch) Reactor concentrationisothermal,perfectlyOperation;beginning iso-pH, mixed gradients, Modeling of andliquid the iso-DOby batch phase Hypothesesusing only.(air (with mechanical sparger); no Reactor Type Notation [Examples] Operation; Modeling Hypotheses (i) simpleExamples: (BBRatch) [9,10] Reactor concentrationisothermal,agitation).perfectly iso-pH,Reactants/biomass mixed gradients, andliquid iso-DOby phase using added (air (with mechanical sparger); at no the (i) simpleExamples: (BBRatch) [9,10] Reactor concentrationisothermal,agitation).perfectlybeginning iso-pH,Reactants/biomass mixed gradients, of liquidand the iso-DOby batch phase using added only.(air (with mechanical sparger); atno the isothermal, iso-pH, and iso-DO (air sparger); (i) simple Batch Reactor perfectly mixedIbidem. liquid phase (with no Examples:(BR) [9,10] perfectlyconcentrationagitation). mixedbeginning Reactants/biomass liquidgradients, of phase the by batch (with using no addedonly. concentrationmechanical at the (i)(ii) simple SeqBRBatch (SeqReactoruential (BR ) Examples:(BR) [9,10] Reactantsconcentrationagitation).gradients, and/orbeginning Reactants/biomass bygradients, biomass using of the mechanical addedby batch using ataddedonly. agitation). themechanical beginning at the Batch-to-batchExamples: R [9eactor),10] Examples: [9,10] Reactantsagitation).of eachbeginning batch,/biomass Reactants/biomass in addedoptimized Ibidem.of the at batch the amounts beginning addedonly. at(to of the be the (ii)Examples: SeqBR (Seq [11,12]uential batch only. Reactants and/orbeginning biomassdetermined) Ibidem.of the added batch atonly. the beginning B(ii)atch-to-batch SeqBR (Seq Ruentialeactor) Reactantsof each and/or batch, biomassin optimizedIbidem. added amounts at the beginning (to be B(ii)atch-to-batchExamples: SeqBR (Seq [11,12] Ruentialeactor) Reactantsof each and/or batch, biomassindetermined) optimizedIbidem. added amounts at the beginning (to be B(ii)atch-to-batchExamples: SeqBR (Seq [11,12] Ruentialeactor) (ii) SeqBR (Sequential Reactantsof each and/or batch, biomassindetermined) optimizedIbidem.Ibidem. added amounts at the beginning (to be B(ii)atch-to-batch(iii)BExamples: SeqBRatch-to-batch Semi- B(Seqatch [11,12] RuentialReactor) (fed-eactor) Reactants and/or biomass added at the beginning of ReactantsIbidem.of each Substrates/bioma and/or batch, biomassindetermined) optimized addedss/supplements amounts at the beginning (to added be Bbatch)atch-to-batchExamples:Examples: Reactor [11,12] R [(11SBReactor),12] or each batch, in optimized amounts (to be determined) duringof each the batch,batch byindetermined) optimizedfollowing aamounts certain (optimal)(to be Examples:FBR). [11,12] (iii) Semi-Batch (fed- determined) Ibidem. Substrates/biomapolicy (to be determined)ss/supplements added batch)(iii)Examples: S emi-ReactorBatch [13–21] (SBR (fed- or duringIbidem. the Substrates/bioma batch by followingss/supplements a certain (optimal) added batch)(iii) S emi-ReactorFBR).Batch (SBR (fed- or duringIbidem. the Substrates/bioma batchpolicy by (to following be determined)ss/supplements a certain (optimal) added batch)(iii)(iii)Examples:S Semi- emi-ReactorFBR).BBatchatch [13–21] ( (fed-batch)SBR (fed- or Ibidem. Substrates/biomass/supplements added duringIbidem. the Substrates/bioma batchpolicy by (to following be determined)ss/supplements a certain (optimal) added (iv)batch)(iii)Examples:R BRPeactor S emi-R eactorFBR).(B (BSBRatchatch [13–21] ( orSBRR (fed-eactorFBR or). during the batch by following a certain (optimal) Examples: [13–21] duringIbidem. the Substrates/bioma batchpolicypolicy by (to (to followingIbidem. be be determined) ss/supplements a certain (optimal) added withbatch)Examples: intermittent/ ReactorFBR). [13–21] (SBRPulse- or Reactantsduring the and/or batchpolicy bybiomass (to following be determined) added a certain during (optimal) the batch Examples:like additionsFBR). [13–21] of (iv) BRP (Batch Reactor in a Pulse-likepolicy additions (to be ofdetermined) equal/uneven solution biocatalyst/substrates).Examples: [13–21] Ibidem. with(iv) BRP intermittent/ (Batch RPeactorulse- Reactantsvolumes, and/or with biomass a Ibidem.certain added frequency during (to the be batch with(iv)(iv) likeBRPBRP intermittent/Examples: additions( B(BatchatchR Reactor eactorPofulse- with inReactants a Pulse-like and/or additions biomassdetermined)Ibidem.Ibidem. of added equal/uneven during the solution batch (iv)intermittent BRP[22–25] (Batch/P ulse-likeReactor withbiocatalyst/substrates).like intermittent/ additions Pofulse- Reactants and/or biomass added during the batch in additions of Reactantsin a Pvolumes,ulse-like and/or withadditions biomass a Ibidem.certain of added equal/uneven frequency during (to the