pH-controlled cell release and biomass distribution of alginate-immobilized Lactococcus lactis subsp. lactis

Klinkenberg, Geir; Lystad, K. Q.; Levine, David; Dyrset, Nils

doi:10.1046/j.1365-2672.2001.01420.x

Cited by 26 publications

(19 citation statements)

References 20 publications

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“…Mechanical properties of the beads are dependent of the initial cell loadings and growth of the strain inside the beads could also change these properties. Release of viable bacteria in the surrounding medium are also reported (Klinkenberg et al, 2001;Scannell et al, 2000) and appears for example when growth occurs in the beads. The microbial colonies reach the surface of the gel bead and this leads to the release of microorganisms.…”

Section: Cells Release From Alginate Matrixmentioning

confidence: 99%

Arsenite oxidation in batch reactors with alginate‐immobilized ULPAs1 strain

Simeonova¹,

Micheva²,

Müller³

et al. 2005

Biotech & Bioengineering

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Arsenic is one of the major groundwater contaminants worldwide. It was previously demonstrated that the beta-proteobacterium Cenibacterium arsenoxidans has an efficient As[III] oxidation ability. The present study was conducted to evaluate the performance of alginate-immobilized ULPAs1 in the oxidation of As[III] to As[V] in batch reactors. A two-level full factorial experimental design was applied to investigate the influence of main parameters involved in the oxidation process, i.e., pH (7-8), temperature (4 degrees C-25 degrees C), kind of nutrient media (2%-20% sauerkraut brine), and arsenic concentration (10-100 mg/L). One hundred milligram per liter of As[III] was fully oxidized by calcium-alginate immobilized cells in 1 h. It was found that the temperature as well as the kind of nutrient media used were significant parameters at a 95% confidence interval whereas only temperature was a significant parameter at a 99% confidence interval. The immobilization of the As[III] oxidizing strain in alginate beads offers a promising way to implement new treatment processes in the remediation of arsenic contaminated waters.

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Section: Cells Release From Alginate Matrixmentioning

confidence: 99%

Arsenite oxidation in batch reactors with alginate‐immobilized ULPAs1 strain

Simeonova¹,

Micheva²,

Müller³

et al. 2005

Biotech & Bioengineering

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“…The possible uses for encapsulated cells in industry, medicine, and agriculture are numerous, ranging from nitrification of domestic waste water (Vogelsang et al, 1997), production of ethanol by yeast (King et al, 1983), lactic acid by lactic acid bacteria (Klinkenberg et al, 2001), monoclonal antibodies by hybridoma cells (Jarvis et al, 1983), and of insulin by entrapment of insulin-producing cells (Lim et al, 1980;Soon-Shiong et al, 1992, 1994. Immobilization in ionically cross-linked alginate provides a simple and safe encapsulation procedure at physiological conditions (Strand et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Visualization of alginate–poly‐L‐lysine–alginate microcapsules by confocal laser scanning microscopy

Strand

Mørch

Espevik

et al. 2003

Biotech & Bioengineering

141

104

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Confocal laser scanning microscopy (CLSM) was used to study the distribution of polymers and cross-linking ions in alginate-poly-L-lysine (PLL) -alginate microcapsules made by fluorescent-labeled polymers. CLSM studies of Ca-alginate gel beads made in the presence and absence of non-gelling sodium ions revealed a more inhomogeneous distribution of alginate in beads formed in the absence of non-gelling ions. In the formation of alginate-PLL capsules, the polymer gradients in the preformed gel core were destabilized by the presence of non-gelling ions in the washing step and in the PLL solution. Ca-alginate gels preserved the inhomogeneous structure by exposure to ion-free solution in contrast to exposure to non-gelling ions (Na(+)). By exchanging Ca(2+) with Ba(2+) (10 mM), extremely inhomogeneous gel beads were formed that preserved their structure during the washing and exposure to PLL in saline. PLL was shown to bind at the very surface of the alginate core, forming a shell-like membrane. The thickness of the PLL-layer increased about 100% after 2 weeks of storage, but no further increase was seen after 2 years of storage. The coating alginate was shown to overlap the PLL layer. No difference in binding could be observed among coating alginates of different composition. This paper shows an easy and novel method to study the distribution of alginate and PLL in intact microcapsules. As the labeling procedures are easy to perform, the method can also be used for a variety of other polymers in other microencapsulation systems.

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“…However, results showed negligible release from immobilized cells after 24 hrs culture, irrespective of the coating material used. 2-It has been reported for alginate beads with entrapped L. lactis that the pH gradient was caused by lactic acid accumulation inside beads, leading to the inactivation of cells in the core of the beads (Klinkenberg et al 2001). Therefore, coating materials with more protection against external components results in a lower permeability for external and internal mass transfer and hence a higher inside inhibition factor, leading to a smaller amount of biomass produced.…”

Section: Immobilized Cell Kineticsmentioning

confidence: 99%