12 results on '"Wang, Feng-Sheng"'
Search Results
2. Optimization of fed-batch fermentation using mixture of sugars to produce ethanol.
- Author
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Hunag, Wen-Hung, Shieh, Grace S., and Wang, Feng-Sheng
- Subjects
FERMENTATION ,SUGARS ,ETHANOL ,SACCHAROMYCES ,BIOCHEMICAL engineering ,STOCHASTIC systems ,PROCESS optimization - Abstract
Abstract: In this study, we introduce a two-phase design approach to optimize a fed-batch fermentation process using a mixture of sugars to produce ethanol. In the first phase, the batch time-series observations were collected and used to construct a kinetic model of Saccharomyces diastaticus LORRE 316. The primary kinetic model was then applied in the second phase to determine the optimal control policy for a fed-batch fermentation process and to retune the kinetic model parameters using the fed-batch information. Two runs were performed in the second phase to achieve the maximum ethanol production rate for the fed-batch fermentation process. Parameter estimation and process optimization were carried out sequentially with a run-to-run approach, which yielded useful estimated parameters even when the model is extrapolated, as observed from cross-validation. [Copyright &y& Elsevier]
- Published
- 2012
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3. Computer-aided biocompatible solvent design for an integrated extractive fermentation–separation process
- Author
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Cheng, Hou-Chieh and Wang, Feng-Sheng
- Subjects
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SOLVENTS , *BIOCOMPATIBILITY , *FERMENTATION , *SEPARATION (Technology) , *COMPUTER-aided design , *EVOLUTIONARY computation , *MATHEMATICAL optimization , *FUZZY systems - Abstract
Abstract: Computer-aided process/solvent design is introduced to find a feasible biocompatible solvent for an extractive fermentation and separation process. The designed biocompatible solvent serves as both the extractant for extractive fermentation and the entrainer for extractive distillation, to yield water-free ethanol. Several goals, such as maximizing production rate and extraction efficiency, and limiting solvent utilization, are simultaneously considered in the optimal solvent design problem. Thus, the design was formulated as a mixed-integer nonlinear optimization problem. A two-phase computational scheme was introduced to solve the problem. The mixed-integer hybrid differential evolution (MIHDE) algorithm was first applied to solve the problem in order to obtain a feasible solution. The feasible solution was then served as an initial starting point for the mixed-integer sequential quadratic programming (MISQP) solver to numerically confirm that the optimal design was achieved. We have compared the crisp and fuzzy approaches to the design problem. The fuzzy goal attainment approach is able to address goal trade-offs and yield an overall satisfactory grade for the problem. [ABSTRACT FROM AUTHOR]
- Published
- 2010
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4. Kinetic modeling of batch fermentation for mixed-sugar to ethanol production.
- Author
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Huang, Wen-Hung and Wang, Feng-Sheng
- Subjects
FERMENTATION ,SUGARS ,ETHANOL ,MICROBIAL growth ,BATCH processing ,PARAMETER estimation ,SYSTEMS theory ,MATHEMATICAL optimization - Abstract
Abstract: We analyze the growth dynamics of Saccharomyces diastaticus LORRE 316 utilizing mixed-sugar to produce ethanol and glycerol, using three alternative modeling frameworks, namely S-system, lin-log model and Monod''s model. The S-system and lin-log model have identical steady-state solutions, but differ in their representation of transients. The global/local optimization method was applied to determine optimal parameter values for each model. Hybrid differential evolution with data collocation was first applied to determine a satisfied solution. Such a global search phase could avoid yielding a premature estimate and alleviate computational burden. The optimal estimate obtained from the global search phase was then served as the initial starting point for a local optimization method to obtain the refined solution. From experimental observation, the dynamical prediction using the S-system is more acceptable than those of the lin-log model and Monod''s model. [Copyright &y& Elsevier]
- Published
- 2010
- Full Text
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5. Optimal trade-off design of integrated fermentation processes for ethanol production using genetically engineered yeast
- Author
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Chen, Ming-Liang and Wang, Feng-Sheng
- Subjects
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ENGINEERING design , *FERMENTATION , *ALCOHOL , *TRANSGENIC plants , *YEAST , *GLUCOSE , *SENSITIVITY analysis - Abstract
Abstract: In this study, we considered a multi-stage integrated extractive fermentation with cell recycling for ethanol production using the genetically engineered Sacchromyces yeast 1400 (pLNH33), which can utilize glucose and xylose as carbon sources to produce ethanol. Each stage consists of a stirred-tank bioreactor, a cell settler and an extractor. A generalized mathematical model was formulated to express the multi-stage integrated process. The aim of the optimization problem was to obtain the maximum overall productivity and conversions subject to the interval inequality constraints for the residual glucose and xylose concentrations and the total sugar supply. A fuzzy goal attainment method was applied to the multiobjective problem in order to achieve the maximum satisfaction for all design requirements. From the computational results, the integrated extractive fermentation with cell recycling (involving the extraction of ethanol from the extractor in situ to alleviate product inhibition) led to an optimal overall productivity that was 8.0% higher than that obtained by the method of continuous fermentation with cell recycling, and about 13-fold higher than that obtained by the method of continuous fermentation without cell recycling. [Copyright &y& Elsevier]
- Published
- 2010
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6. Optimal process/solvent design for ethanol extractive fermentation with cell recycling
- Author
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Cheng, Hou-Chieh and Wang, Feng-Sheng
- Subjects
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COMPUTER-aided design , *ALCOHOL , *FERMENTATION , *SOLVENTS , *BIOCOMPATIBILITY , *EXTRACTION (Chemistry) - Abstract
Abstract: In this study, the computer-aided process/solvent design is introduced to find an optimal biocompatible solvent and to maximize the ethanol production rate simultaneously for the single- or double-stage extractive fermentation process with cell recycling. Such a process/solvent design problem is formulated as a mixed-integer nonlinear programming problem that is solved by mixed-integer hybrid differential evolution in order to obtain a global design. The double-stage process can use a smaller amount of fresh solvent to increase ethanol productivity compared with that of the single-stage process, but it will also decrease overall conversion. Comparing the case studies, the simultaneous process/solvent design could yield higher overall ethanol productivity than that of the process design. The maximum ethanol production rate for the double-stage extractive fermentation with cell recycling was about 10-fold higher than that of continuous fermentation and about twofold higher than that of continuous fermentation with cell recycling. [Copyright &y& Elsevier]
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- 2008
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7. Optimal biocompatible solvent design for a two-stage extractive fermentation process with cell recycling
- Author
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Cheng, Hou-Chieh and Wang, Feng-Sheng
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SOLVENTS , *FERMENTATION , *DESIGN , *BIOCHEMICAL engineering , *INDUSTRIAL microbiology - Abstract
In this study, crisp and fuzzy multiple-goal optimization approaches are respectively introduced to design an optimal biocompatible solvent to a two-stage extractive fermentation with cell recycling for ethanol production. When designing a biocompatible solvent for the extractive fermentation process, many issues, such as extractive efficiency, conversion, amount of solvent utilized and so on, have to be considered. An interactive multiple-goal design procedure is introduced to determine a trade-off result in order to satisfy such contradicted goals. Both approaches could be iterated to solve the interactive multiple-goal design problem in order to yield a trade-off result. However, the crisp optimization design is a tedious task that requires the designer to provide various pairs of the upper bounds for the design problem to obtain the corresponding solution. The fuzzy optimization approach is able to be trade-off several goals simultaneously and to yield the overall satisfactory grade for the product/process design problem. [Copyright &y& Elsevier]
- Published
- 2008
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8. Trade-off optimal design of a biocompatible solvent for an extractive fermentation process
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Cheng, Hou-Chieh and Wang, Feng-Sheng
- Subjects
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CHEMICAL engineering , *SOLVENTS , *MATHEMATICAL optimization , *FUZZY mathematics , *NONLINEAR programming , *FERMENTATION - Abstract
In this study, crisp and flexible optimization approaches are, respectively, introduced to design an optimal biocompatible solvent for an extractive fermentation process. The optimal design problem is formulated as a mixed-integer nonlinear programming model in which performance requirements of the compounds are reflected in the objective and the constraints. In general, the requirements for the objective and constraints are not rigid; consequently, the flexible or fuzzy optimization approach is applied to soften the rigid requirement for maximization of the extraction efficiency and to consider the mass flow rate and biocompatibility of solvent as the softened inequality constraints to the solvent design problem. Having elicited the membership function for the objective function and the constraint, the optimal solvent design problem can be formulated as a flexible goal attainment problem. Mixed-integer hybrid differential evolution is applied to solve the problem in order to find a satisfactory design. [Copyright &y& Elsevier]
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- 2007
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9. Kinetic modeling using S-systems and lin-log approaches
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Wang, Feng-Sheng, Ko, Chih-Lung, and Voit, Eberhard O.
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MECHANICS (Physics) , *ESCHERICHIA , *AMINO acids , *ENTEROBACTERIACEAE - Abstract
Abstract: We analyze the growth dynamics and production of an industrially interesting amino acid in a recombinant Escherichia coli strain, using in parallel two alternative modeling frameworks, namely S-systems and lin-log models. These models have identical steady-state solutions, but differ in their representation of transients. The models were parameterized with data from two bioprocesses that differed in their initial culture concentrations and then used to predict responses under yet a different initial culture regimen. Among the S-system models, several alternatives representing slightly different pathway structures, were tested. All were found to be capable of capturing the dynamics of all variables in the test systems and also of predicting the dynamic responses under new conditions. The lin-log models also captured the dynamics, but not as well as the S-system models. A probable reason for the inferior performance of lin-log models is their intrinsic property of not representing situations well where variable concentrations are moderately small. [Copyright &y& Elsevier]
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- 2007
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10. Run-to-run fed-batch optimization for protein production using recombinant Escherichia coli
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Ko, Chih-Lung and Wang, Feng-Sheng
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ESCHERICHIA coli , *PROTEIN synthesis , *ENTEROBACTERIACEAE , *MICROBIOLOGICAL synthesis - Abstract
Abstract: A two-phase design approach is introduced to determine the optimal feed rate, fed glucose concentration and fermentation time to maximize protein productivity using recombinant Escherichia coli BL21 (pBAW2) strain. The first phase is applied to determine a primary S-system kinetic model using batch time-series data. Two runs were carried out in the second phase to achieve the maximum protein productivity for the fed-batch fermentation process. The computational results using the S-system kinetic model obtained from the second run are in better agreement with the experiments than those using the kinetic model obtained from batch time-series data. For cross-validation, two extra fed-batch experiments with different feed strategies were carried out for comparison with the optimal fed-batch result. From the experimental results, this approach could improve productivity by at least 3%. [Copyright &y& Elsevier]
- Published
- 2006
- Full Text
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11. S-system approach to modeling recombinant Escherichia coli growth by hybrid differential evolution with data collocation
- Author
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Ko, Chih-Lung, Wang, Feng-Sheng, Chao, Yun-Peng, and Chen, Te-Wei
- Subjects
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ESCHERICHIA coli , *ENTEROBACTERIACEAE , *ESTIMATION theory , *PARAMETER estimation - Abstract
Abstract: In this study, we have established a suitable model to describe the dynamic characteristic of an aspartase-overproducing Escherichia coli strain. A traditional Monod model and power-law models are respectively applied to describe the dynamic behaviors. When the model structure was selected, the parameter values of the model should be determined by the global/local optimization method. There are two major challenges, numerical integration for differential equations and finding global parameter values. In this study, we introduce hybrid differential evolution, which is a variant of genetic algorithms, to avoid obtaining a premature solution. In addition, we apply a modified collocation method to avoid numerical integration. The Monod''s model could only predict the growth characteristic of the recombinant E. coli, qualitatively. The S-system representation could suit for constructing the model structure of the microbial growth. [Copyright &y& Elsevier]
- Published
- 2006
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12. Performance analysis and fuzzy optimization of a two-stage fermentation process with cell recycling including an extractor for lactic acid production
- Author
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Wang, Feng-Sheng and Lin, Kun-Jun
- Subjects
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LACTIC acid , *DECISION making , *GLUCOSE , *MATHEMATICAL optimization - Abstract
In this study, we consider a two-stage fermenter with cell recycling including an extractor to produce lactic acid. When the extractor was omitted, the proposed process was simplified to two special processes. Under the same operating conditions, we compared the overall lactic acid productivity and glucose conversion for the three processes. The proposed fermentation process was more efficient than the other processes. To simultaneously obtain the maximum productivity and conversion, the problem is formulated as a fuzzy multiobjective optimization problem. The fuzzy decision is introduced to convert the multiobjective fuzzy optimization problem into the fuzzy goal attainment problem. Hybrid differential evolution is applied to solve the fuzzy goal attainment problem to obtain a global Pareto solution. [Copyright &y& Elsevier]
- Published
- 2003
- Full Text
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