Scale-up and application of a cyclone reactor for fermentation processes

Weuster‐Botz, Dirk; Hünnekes, E.; Hartbrich, A.

doi:10.1007/s004490050467

Cited by 7 publications

(4 citation statements)

References 15 publications

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“…Despite the long history of GAs and their current widespread use, there have been only a few examples of using GAs in fermentation technology. For instance, recently, WeusterBotz et al (56)(57)(58)(59) and Zuzek et al (67) used GAs to study medium optimization (for instance, to maximize hydrocortisone ⌬ 1 -dehydrogenase activity in Arthrobacter simplex cultures in a synthetic medium [58]). In our proof of principle experiments we examined whether it is feasible to use GAs to study an experimental system that is significantly more complex.…”

Section: Discussionmentioning

confidence: 99%

Efficient Improvement of Silage Additives by Using Genetic Algorithms

Davies

Merry

Kell

et al. 2000

Appl Environ Microbiol

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The enormous variety of substances which may be added to forage in order to manipulate and improve the ensilage process presents an empirical, combinatorial optimization problem of great complexity. To investigate the utility of genetic algorithms for designing effective silage additive combinations, a series of small-scale proof of principle silage experiments were performed with fresh ryegrass. Having established that significant biochemical changes occur over an ensilage period as short as 2 days, we performed a series of experiments in which we used 50 silage additive combinations (prepared by using eight bacterial and other additives, each of which was added at six different levels, including zero [i.e., no additive]). The decrease in pH, the increase in lactate concentration, and the free amino acid concentration were measured after 2 days and used to calculate a "fitness" value that indicated the quality of the silage (compared to a control silage made without additives). This analysis also included a "cost" element to account for different total additive levels. In the initial experiment additive levels were selected randomly, but subsequently a genetic algorithm program was used to suggest new additive combinations based on the fitness values determined in the preceding experiments. The result was very efficient selection for silages in which large decreases in pH and high levels of lactate occurred along with low levels of free amino acids. During the series of five experiments, each of which comprised 50 treatments, there was a steady increase in the amount of lactate that accumulated; the best treatment combination was that used in the last experiment, which produced 4.6 times more lactate than the untreated silage. The additive combinations that were found to yield the highest fitness values in the final (fifth) experiment were assessed to determine a range of biochemical and microbiological quality parameters during full-term silage fermentation. We found that these combinations compared favorably both with uninoculated silage and with a commercial silage additive. The evolutionary computing methods described here are a convenient and efficient approach for designing silage additives.The ensiling of forage crops in order to obtain winter or buffer feed for ruminant livestock is widely practiced in advanced management systems in temperate regions. The aim is to preserve crops having high moisture contents by encouraging rapid fermentation of water-soluble carbohydrates (WSC) in the crops to lactic acid by epiphytic lactic acid bacteria (LAB), which decreases the pH and inhibits the activities of plant enzymes and pathogenic or spoilage bacteria that could decrease the nutritive value of the silage.Grass is the predominant crop ensiled in Europe, and 50 million tons of grass silage are made each year in the United Kingdom alone (23, 61, 62). As with maize, the main crop ensiled in the United States, high WSC levels and a low buffering capacity in this crop are conducive to rapid acidification by epip...

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Section: Discussionmentioning

confidence: 99%

Efficient Improvement of Silage Additives by Using Genetic Algorithms

Davies

Merry

Kell

et al. 2000

Appl Environ Microbiol

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“…pressure, temperature as well as hydrocyclone geometry on the recovery and concentration of yeast cells. Moreover, Weuster-Botz et al [84] developed a fermentation process with high oxygen transfer for the continuous methanol controlledproduction of formate dehydrogenase with Candida boidinii. They applied three geometrically similar cyclones with different liquid volumes (0.5, 2.5 and 15L) and obtained more than 100% improvement in dry cell mass concentration and about 100% improvement in the enzyme space-time yield.…”

Section: Biological Applications Of Hydrocyclonesmentioning

confidence: 99%

The Potential of Hydrocyclone Application for Mammalian Cell Separation in Perfusion Cultivation Bioreactors

Atlam¹

2013

Int. J. Biotech. Well. Indus.

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Hydrocyclones have been traditionally applied for long times in many industrial fields, such as in mineral processing and mining, chemical and petrochemical, and food industries. They have many characteristics that favor them as separation system in solid/liquid, gas/liquid and liquid/liquid processes. During the last two decades, they have been evaluated for their possible application in the separation of microbial and mammalian cells. Nowadays, mammalian cells are widely used for the production of a large number of valuable therapeutic proteins, antibodies, hormones and vaccines. This review highlights the potential of the application of hydrocyclones for mammalian cell separation in continuous perfusion biorecators. The discussion will cover the structure of hydrocyclone, mechanism of separation inside hydrocyclones, different theories describing the separation process, as well as the effect of changing different geometrical variables on the efficiency and performance of the separation process. Furthermore, we will focus on the latest developments achieved in the field of separation of living cells in both laboratory and pilot plant cultivation scales.

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“…In particular, oxygen is generally known as a limiting factor for numerous oxidation processes, aerobic fermentations, and wastewater treatment. [4][5][6] Many processes have been developed and improved significantly regarding oxygen entry through membrane technology, [7] thin silicon tubes, [8,9] or cyclone reactors [10] for aeration. Dispersive methods potentially inactivate the enzymes by the complex effects of hydrodynamic shear stress and the gas/liquid interface.…”

Section: Introductionmentioning

confidence: 99%