[56] Continuous production of high-fructose syrup by cross-linked cell homogenates containing glucose isomerase

Poulsen, Poul Børge; Zittan, L.

doi:10.1016/s0076-6879(76)44058-2

Cited by 15 publications

(3 citation statements)

References 6 publications

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“…Lactose hydrolysis, in addition, prevents lactose crystallization on cooling or concentration and may accelerate flavor development during processing. Moreover, lactose hydrolysis in whey ultrafiltrate gives rise to sweet sugar syrup, which can be used to replace conventional sweeteners (29,30). Finally, the presence of lactose in wastewater of dairy industry creates environmental pollution problems, particularly when large quantities of whey are discharged, because these polluted waters constitute an excellent culture broad for noxious microorganisms (31)(32)(33).…”

Section: Introductionmentioning

confidence: 99%

Production of Low-Lactose Milk by Means of Nonisothermal Bioreactors

et al. 2004

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The effect of the immobilization time on the activity of immobilized beta-galactosidase from K. lactis was investigated. Six biocatalytic membranes, different only for the time of the enzyme immobilization, were obtained by using nylon membranes grafted with glycidyl methacrylate (GMA) and activated by hexamethylenediamine (HMDA) and glutaraldehyde (Glu), used as spacer and coupling agent, respectively. Comparison between the isothermal and nonisothermal yield of these biocatalytic membranes was carried out in the process of lactose hydrolysis in milk. All of the results, reported as a function of the immobilization time, have evidenced the influence of our variable parameter on the activity of the catalytic membranes. The membrane giving highest yield under isothermal and nonisothermal conditions was that obtained with 2 h of immobilization time. The industrial application of these membranes has been discussed in terms of percentage reduction of the production times.

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Section: Introductionmentioning

confidence: 99%

Production of Low-Lactose Milk by Means of Nonisothermal Bioreactors

et al. 2004

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“…There are no obvious competitors with the various immobilized cell processes even though the activities per unit of reactor volume could be improved. Although GI is produced by highly developed strains of organism that give relatively high enzyme yields the specific activity of the enzyme (on a protein basis) is low and may be further lowered very significantly on immobiliza tion (Poulsen & Zittan (1977) quote only a 20-30% retention of measurable enzyme activity). Thus a soluble, purified GI immobilized on to a solid support material should have a far higher activity per unit of reactor volume.…”

Section: (C) Proteinsmentioning

confidence: 99%

Immobilized cells

Bucke

Brown²

1983

Phil. Trans. R. Soc. Lond. B

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Cells of microbes and of higher organisms may be immobilized by a number of methods for a variety of purposes. Although the study of cell immobilization is comparatively novel, the methods that have been developed are very effective and there are few indications that further, greatly superior techniques are likely to evolve. Cells are best immobilized by aggregation, by adsorption onto a support material or by entrapment within gels, of which the natural polysaccharides K-carrageenan and calcium alginate have proved the most useful. Aggregation of cells usually involves heat treatment or chemical cross-linkage and causes total loss of cell viability. It is most suitable for the immobilization of cells so as to contain a single enzymic activity: many of the commercial preparations of glucose isomerase consist of aggregated cells. Adsorption of cells to surfaces is a gentle and simple technique: efficient immobilization is aided by the correct choice of pore size in the support material. Cell viabilities and activities are retained but adsorbed cells may be removed from supports fairly readily. Entrapment within gels allows the retention of cell viability and activity and by supplying full growth media, cells can be made to multiply within the beads of gel, giving very high cell densities. Polyacrylamide has been used satisfactorily for cell entrapment but has been superseded in industrial processes by K-carrageenan or calcium alginate. Industrial processes known to employ immobilized cells include the production of L-malic acid and L-aspartic acid and various steroid conversions. Very many other processes using immobilized cells have been studied at the academic level. Immobilization in polysaccharide gels, in particular, sometimes gives unexpected properties of longevity or activity to cells. These phenomena are largely unexplained but may be due to the gel material’s influencing the chemical composition of the immediate environment of the cells. The use of immobilized cells has not yet made a large impact on the fermentation industries but these are early days in the development of new technology and it is to be expected that processes involving immobilized cells will find wider industrial use in the near future.

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“…Glucose can be converted to fructose using the enzyme Glucose Isomerase (GI, EC 5.3.1.5), which can be obtained from various microbial resources such as Clostridium thermosulfurogenes [1], Streptomyces violaceoniger [2] and Thermus aquaticus [3]. As described above, Fructose is useful to make higher industrial value products such as high fructose corn syrup (HFCS) [4][5][6]. Since fructose absorption in the intestine is less than glucose [7], it is widely used in the food industry as healthier alternative for glucose [8].…”

Section: Introductionmentioning

confidence: 99%