• Journal of Microbiology
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• v.44 no.2
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• pp.233-242
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• 2006

The objectives of this study were to optimize submerged culture conditions of a new fungal isolate, Ganorderma resinaceum, and to enhance the production of bioactive mycelial biomass and exopolysaccharides (EPS) by fed-batch culture. The maximum mycelial growth and EPS production in batch culture were achieved in a medium containing 10 g/l glucose, 8 g/l soy peptone, and 5 mM $MnCl_2$ at an initial pH 6.0 and temperature $31^{\circ}C$. After optimization of culture medium and environmental conditions in batch cultures, a fed-batch culture strategy was employed to enhance production of mycelial biomass and EPS. Five different EPS with molecular weights ranging from 53,000 to 5,257,000 g/mole were obtained from either top or bottom fractions of ethanol precipitate of culture filtrate. A fed-batch culture of G. resinaceum led to enhanced production of both mycelial biomass and EPS. The maximum concentrations of mycelial biomass (42.2 g/l) and EPS (4.6 g/l) were obtained when 50 g/l of glucose was fed at day 6 into an initial 10 g/l of glucose medium. It may be worth attempting with other mushroom fermentation processes for enhanced production of mushroom polysaccharides, particularly those with industrial potential.

• Journal of applied mathematics & informatics
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• v.24 no.1_2
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• pp.387-397
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• 2007

According to the controllability of pulse times and the amount of jumps in the states at these times in the process of fed-batch culture producing 1,3-propanediol, this paper proposes a terminal optimal control model, whose constraint condition is the nonlinear impulsive delay system. The existence of optimal control is discussed and an optimization algorithm which is applied to each subinternal over one cycle for this optimal control problem is constructed. Finally, the numerical simulations show that the terminal intensity of producing 1,3-propanediol has been increased obviously.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1979.10a
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• pp.242-242
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• 1979

The general efforts of applied research and development can be divided into product development, process development, process design, process equipment design, and operation The fed batch culture as one effort of theprocess development in fermentation industry has been practiced since the early times of human history. One particular industrial application with long history is in the cultivation of the baker's yeast where the glucose effect at relatively high glucose concentration is the general rule.

• Microbiology and Biotechnology Letters
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• v.20 no.6
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• pp.668-676
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• 1992

For the purpose of optimizing poly-l3-hydroxybutyrate (PHB) production from Alcaligenes eutrophus, two-stage fed-batch culture was adopted. In this system, specifk growth rate was maximized during the first stage whereas specific production rate was maximized during the second stage. The optimal concentrations of glucose and ammonium chloride were 16.6 and 0.54 g/I in the growth stage and 20.0 and 0.07 g/l in the production stage, respectively. Proportional feedback control considering time lag was suggested for PHB production process and a simulator was developed for real-time control purpose.

• Journal of Microbiology and Biotechnology
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• v.31 no.9
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• pp.1305-1310
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• 2021

Shikimate is a key high-demand metabolite for synthesizing valuable antiviral drugs, such as the anti-influenza drug, oseltamivir (Tamiflu). Microbial-based strategies for shikimate production have been developed to overcome the unstable and expensive supply of shikimate derived from traditional plant extraction processes. In this study, a microbial cell factory using Corynebacterium glutamicum was designed to overproduce shikimate in a fed-batch culture system. First, the shikimate kinase gene (aroK) responsible for converting shikimate to the next step was disrupted to facilitate the accumulation of shikimate. Several genes encoding the shikimate bypass route, such as dehydroshikimate dehydratase (QsuB), pyruvate kinase (Pyk1), and quinate/shikimate dehydrogenase (QsuD), were disrupted sequentially. An artificial operon containing several shikimate pathway genes, including aroE, aroB, aroF, and aroG were overexpressed to maximize the glucose uptake and intermediate flux. The rationally designed shikimate-overproducing C. glutamicum strain grown in an optimized medium produced approximately 37.3 g/l of shikimate in 7-L fed-batch fermentation. Overall, rational cell factory design and culture process optimization for the microbial-based production of shikimate will play a key role in complementing traditional plant-derived shikimate production processes.

• KSBB Journal
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• v.15 no.2
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• pp.181-187
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• 2000

The production of heterologous protein using GAL promoter in conventional S. cerevisiae has several problems to s이ve for c commercialization. In this research, S. cerevisiae mutant(reg1-501, gaI1), which cannot use galactose and has alleviated g glucose repression level, is used as host for optimizing induction of GAL promoter. In this experiment, the effects of specific g growth rate on specific recombinant protein expression rate were tested in both cases and optimum fed batch fermentation m method was obtained in both cases. Through these experiments, optimum condition of recombinant protein production by G GAL promoter using S. cerevisiae mutant (reg1-501, gal1) were found.

• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.4
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• pp.275-287
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• 2000

Fermentation strategies for recombinant protein production in Pichia pastoris have been investigated and are reviewed here. Characteristics of the expression system, such as phenotypes and carbon utilization, are summarized. Recently reported results such as growth model establishment, app58lication of a methanol sensor, optimization of substrate feeding strategy, DOstat controller design, mixed feed technology, and perfusion and continuous culture are discussed in detail.

• KSBB Journal
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• v.6 no.1
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• pp.15-25
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• 1991

The optimal glucose concentration for the high-density culture of recombinant yeasts was obtained using dynamic simulation. An adaptive and predictive algoritilm complimented by the rule base was proposed for the control of the fed-batch fermentation process. The measurement of process variables has relatively long sampling period and relatively long time delay characteristics. As one of the solution on these problems, prediction techniques and rule bases were added to a classical recursive identification and control algorithm. Rule bases were used in the determination of control input considering the difference between the predicted value and the measured value. A mathelnatical model was used in the estimation and interpretation of the changes of state variables and parameters. Better performances were obtained by employing the control algorithm proposed in the present study compared to the conventional adaptive control method.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.6
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• pp.459-464
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• 2004

The objective of this study is to improve cephalosporin C (CPC) production byoptimization of medium and culture conditions. A statistical method was introduced to optimize the main culture medium. The main medium for CPC production was optimized using a statistical method. Glucose and corn steep liquor (CSL) were found to be the most effective factors for CPC production. Glucose and CSL were optimized to 2.84 and $6.68\%$, respectively. CPC produc­tion was improved $50\%$ by feeding of $5\%$ rice oil at day 3rd and 5th day during the shake flask culture of C acremonium M25. The effect of agitation speeds on CPC production in a 2.5-L bio­reactor was also investigated with fed-batch mode. The maximum cell mass (54.5 g/L) was obtained at 600 rpm. However, the maximum CPC production (0.98 g/L) was obtained at 500 rpm. At this condition, the maximum CPC production was improved about $132\%$ compared to the re­sult with batch flask culture.

• Microbiology and Biotechnology Letters
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• v.28 no.5
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• pp.291-297
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• 2000

A strain producing high levels of compaction was isolated from soil and identified as Penicillium sp. Y-8515 based on the morphological characteristics and ribosomal RNA sequence analysis. Optimization of several different carbon and nitrogen sources for the effective production of compaction was performed resulting in the medium compositions containing 5%(w/v) glucose, 1.0 % soybean meal, 0.5% yeast extract, 0.5%(NH$_4$)$_2$$SO_4$, 0.25%,$ NaH_2$$PO_4$, 0.25% $CaCO_3$. The fixed con-centration of glucose(5%, w/v) and relatively lower concentrations(less than 2.5%, w/v) of soybean meal stimu-lated the transformation of the growth morphology from filamentous to pellet form. Comparing to that by filamentous form, the production of compactin by pellet form increased up to 1.5 folds. In a fed-batch fermentation, continuous feeding of the mixture of glucose and nitrogen source at the ratio of 10:1 showed 3.5-fold more produc-tion yield of compaction comparing to the batch mode.