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| 2. |
- Adlercreutz, Patrick, et al.
(författare)
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Oxygen supply to immobilized cells : 1. Oxygen production by immobilized Chlorella pyrenoidosa
- 1982
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Ingår i: Enzyme and Microbial Technology. - : Elsevier BV. - 0141-0229. ; 4:5, s. 332-336
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Tidskriftsartikel (refereegranskat)abstract
- Oxygen supply at high cell densities of aerobic organisms is a great problem in immobilized cell preparations. To investigate the possibility of in situ oxygen generation the alga Chlorella pyrenoidosa was immobilized on alginate beads. The conditions for optimal oxygen production were investigated and in long term experiments the preparations were successful for at least 30 days.
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| 3. |
- Adlercreutz, Patrick, et al.
(författare)
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Oxygen supply to immobilized cells : 2. Studies on a coimmobilized algae-bacteria preparation with in situ oxygen generation
- 1982
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Ingår i: Enzyme and Microbial Technology. - : Elsevier BV. - 0141-0229. ; 4:6, s. 395-400
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Tidskriftsartikel (refereegranskat)abstract
- A coimmobilized mixed culture of algae, Chlorella pyrenoidosa, and bacteria, Gluconobacter oxydans, has been studied. The conversion of glycerol to dihydroxyacetone(1,3-dihydroxy-2-propanone), catalysed by the bacteria, was used to indicate the oxygen supply in the immobilized preparation. The oxygen produced by the algae in the coimmobilized preparation was used by the bacteria more effectively than when the cells were immobilized separately and mixed within the reactor. A preparation consisting of only bacteria and no algae was much less effective. The coimmobilized preparation was used in the continuous production of dihydroxyacetone for six days without any significant loss of activity.
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| 4. |
- Adlercreutz, Patrick, et al.
(författare)
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Oxygen supply to immobilized cells - 3. Oxygen supply by hemoglobin or emulsions of perfluorochemicals
- 1982
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Ingår i: European Journal of Applied Microbiology and Biotechnology. - 0171-1741. ; 16:4, s. 165-170
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Tidskriftsartikel (refereegranskat)abstract
- Oxygen supply is a critical point in technical processes when aerobic cells are used in immobilized preparations. This report concerns the use of hemoglobin or emulsions of perfluorochemicals (completely fluorinated organic compounds) to carry oxygen to immobilized cells. Both methods work well and do not seem to harm the cells. The perfluorochemical method of improving oxygen supply showed a higher operational stability than the hemoglobin method.
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| 5. |
- Adlercreutz, Patrick, et al.
(författare)
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Oxygen supply to immobilized cells - 4. Use of p-benzoquinone as an oxygen substitute
- 1984
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Ingår i: Applied Microbiology and Biotechnology. - 0175-7598. ; 20:5, s. 296-302
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Tidskriftsartikel (refereegranskat)abstract
- Oxygen supply is a critical point in technical processes when aerobic cells are used in immobilized preparations. In this study p-benzoquinone is used as a substitute for oxygen in the oxidation of glycerol to dihydroxyacetone by immobilized Gluconobacter oxydans cells. The reaction rate was much higher when p-benzoquinone was used compared to when oxygen was used. In an experiment with free cells p-benzoquinone gave a rate more than four times that of oxygen, and with immobilized cells the difference was even greater. p-benzoquinone is more effective than oxygen because it gives a higher maximal reaction rate (the reason for this fact is discussed) and because it is more soluble in water than oxygen. The operational stability of the process is comparatively good. In one experiment the productivity decreased from 60 to 10 mmol/h·g over an 8-day period when p-benzoquinone was used. When oxygen was used in a similar experiment the productivity decreased from 14 to 6 mmol/h·g. The byproduct formed from p-benzoquinone, hydroquinone, can be oxidized to p-benzoquinone which can be re-used. Seven succesive regenerations of p-benzoquinone were performed without any loss of efficiency.
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