Optimum CFST bioreactor design: Experimental study using batch growth parameters for saccharomyces cerevisiae producing ethanol

Abstract

An optimum CFST bioreactor design equation is presented which can be used with linear growth-associated product inhibition models. Batch experiments were performed to determine Saccharomyces cerevisiue growth parameters required for solving the optimum design equation.The three bioreactors were designed in decreasing volumes to achieve theoretical glucose conversions of 99.9% and 99.99%. At steady state, the bioreactors appeared to reach the theoretical conditions as long as the flowrates were held equal or slightly below the optimum conditions. At very low flowrates, biomass death was observed in downstream reactors while at high flowrates, the theoretical conversions were not achieved. The experimental results confirm that optimally designed bioreactors can offer lower processing volumes to achieve high substrate conversions as compared to single CFST bioreactors.On prisente une Cquation de conception de bioriacteurs CFST pouvant &tre utilisCe avec des modkles d'inhibition de produits associCs croissance IinCaire. Des exptriences discontinues ont CtC menCes pour diterminer les paramktres de croissance de Succharomyces cerevisiae requis pour risoudre I'bquation de conception optimale.On a cony les trois biortacteurs de volume dicroissant afin d'obtenir des conversions theoriques de glucose de 99.9 et 99,99%. En rkgime permanent, les bioreacteurs semblent atteindre !es conditions thioriques tant yue les dCbits denieurent egaux ou ICgerement inferieurs a ceux des conditions optimales. A des dtbits trks faibles, on constate une mortalit6 de la biomasse dans les rCacteurs en aval tandis qu'k de forts dkbits, les conversions thCoriques ne sont pas atteintes. Lcs rksultats expkrimentaux confirment que les bioreacteurs conqus dans des conditions optimales peuvent offrir de plus faibles volumes de traitement pour des conversions de substrats klevees comparativement aux bioreacteurs CFST seuls.

Optimal design for CSTR's in series using reversible Michaelis-Menten reactions

“…Gooijer et al [2] have optimized a series of mixed reactors containing immobilized invertase obeying Michaelis-Menten kinetics. The mathematical procedure developed by Luyben and Tramper [1] has been used to optimize CSTR's in series used for microbial growth using variety of growth kinetic models [3,4]. They have found that the optimum holding time in downstream reactors always decreases.…”

Optimal design of interconnected bioreactors: New results

“…It was also verified that these results hold for biological reactions inhibited by the product w Ž .x cf. Wall and Hill 1992 . It should be noticed that the results of Hill and Robinson were in accordance with the ''fourth polynomial equation'' first proposed in 1966 by Bischoff to optimally compute the optimal concentrations of substrate in w Ž .…”

Optimum Design of N Continuous Stirred-Tank Bioreactors in Series for Fermentation Processes Based on Simultaneous Substrate and Product Inhibition

“…Ghose and Tyagi [2] showed that the volume required to achieve the same ethanol productivity is 58% less for two equal-size fermenters in series compared to one reactor. Using experimental data, Wall and Hill [22] confirmed the optimal design predictions for substrate (sugar), biomass and the product (ethanol) for each of the three unequal-size bioreactors in series used. Kalogeris et al [23] successfully used two CSTRs in series for biodegradation of the highly toxic chemical 1,3-DCP (200 mg/L); 68% substrate removal was achieved.…”

“…Experimental results confirmed the optimal design predictions for substrate, product and biomass concentrations for each of the 3 unequal-size reactors in series. [22] Minimum total volume of CSTRs in series based on substrate and product inhibition kinetic model obtained from [2].…”

“…Many fermentation processes are carried out in CSTRs in series that are usually equal in size. A number of investigators have studied the optimum design (not necessarily equal volume) of CSTRs in series with different cell growth and enzyme kinetics [20,22,28,29]. Previous studies reported the effect of either substrate or product inhibition on the optimum design of multistage bioreactors in series.…”