Effect of exogenous calcium on morphological development and biopolymer synthesis in the fungus Aureobasidium pullulans

Madi, Nuri S.; McNeil, Brian; Harvey, Linda M.

doi:10.1016/s0141-0229(96)00232-3

Cited by 13 publications

(5 citation statements)

References 22 publications

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“…The pullulan content of the polysaccharide produced by the alginate-entrapped ATCC 42023 cells grown on glucose or sucrose was similar to the pullulan content of the polysaccharide synthesized by corn syrup-grown ATCC 201253 cells entrapped in calcium alginate or carrageenan beads during either the initial or second production cycle of 168 h [9,10]. A prior study showed that the presence of calcium ions stimulated production of polysaccharides with two different molecular weights by A. pullulans [17]. With this fungus also able to synthesize a different polysaccharide than pullulan [18], the presence of this alternate extracellular polysaccharide in the medium could explain the low pullulan content of the polysaccharide produced by the alginate-entrapped cells used during this study ( Table 2).…”

Section: Hours Cycle and Polysaccharide Concentration A)supporting

confidence: 53%

Effect of carbon source on polysaccharide production by alginate‐entrapped Aureobasidium pullulans ATCC 42023 cells

West

2011

J. Basic Microbiol.

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The production of the exopolysaccharide pullulan using entrapped cells of the fungus Aureobasidium pullulans ATCC 42023 was investigated relative to carbon source. Fungal cells grown on glucose or sucrose as a carbon source were entrapped in calcium alginate beads and found to be capable of synthesizing the polysaccharide for two production cycles. Using 2.5% glucose or sucrose as a carbon source, productivity was 18.3 or 21.9 mg polysaccharide/g cells × h, respectively after the initial production cycle and decreased to 9.6 or 8.5 mg polysaccharide/g cells × h, respectively, after the second production cycle. Independent of carbon source, the entrapped fungal cells exhibited a higher yield during the initial cycle than the second production cycle while the entrapped ATCC 42023 cells elaborated a polysaccharide with a higher pullulan content during the second production cycle compared to the initial production cycle.

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Section: Hours Cycle and Polysaccharide Concentration A)supporting

confidence: 53%

Effect of carbon source on polysaccharide production by alginate‐entrapped Aureobasidium pullulans ATCC 42023 cells

West

2011

J. Basic Microbiol.

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“…A shear rate (∂ u /∂ y ) of 300 s −1 was used, which was previously found to be the mean shear rate at usual operating conditions of shake flasks (Peter et al, ). Further relevant viscosity studies of shake flask cultures, conducted at shear rates differing from 300 s −1 are presented in Burns et al (), Byrne and Ward (), Madi et al (), and Peña et al (). Such increasing viscosities in combination with the presented increases of liquid film thickness (Figs.…”

Section: Resultsmentioning

confidence: 99%

Liquid films on shake flask walls explain increasing maximum oxygen transfer capacities with elevating viscosity

Giese

Azizan

Kümmel

et al. 2013

Biotech & Bioengineering

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In biotechnological screening and production, oxygen supply is a crucial parameter. Even though oxygen transfer is well documented for viscous cultivations in stirred tanks, little is known about the gas/liquid oxygen transfer in shake flask cultures that become increasingly viscous during cultivation. Especially the oxygen transfer into the liquid film, adhering on the shake flask wall, has not yet been described for such cultivations. In this study, the oxygen transfer of chemical and microbial model experiments was measured and the suitability of the widely applied film theory of Higbie was studied. With numerical simulations of Fick's law of diffusion, it was demonstrated that Higbie's film theory does not apply for cultivations which occur at viscosities up to 10 mPa s. For the first time, it was experimentally shown that the maximum oxygen transfer capacity OTRmax increases in shake flasks when viscosity is increased from 1 to 10 mPa s, leading to an improved oxygen supply for microorganisms. Additionally, the OTRmax does not significantly undermatch the OTRmax at waterlike viscosities, even at elevated viscosities of up to 80 mPa s. In this range, a shake flask is a somehow self-regulating system with respect to oxygen supply. This is in contrary to stirred tanks, where the oxygen supply is steadily reduced to only 5% at 80 mPa s. Since, the liquid film formation at shake flask walls inherently promotes the oxygen supply at moderate and at elevated viscosities, these results have significant implications for scale-up.

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“…Thus, the effect of Ca 2+ on PMLA production in a 7.5 L bioreactor was investigated in the following study. pullulans, and the exogenous Ca 2+ could increase yeast-like cell formation, thus reducing the transition of yeast cells to mycelia [20]. It is worth mentioning that the yeast-like form A. pullulans was the main PMLA producer [18].…”

Section: Effect Of Co 3 2on Pmla Productionmentioning

confidence: 98%

High molecular weight β-poly(l-malic acid) produced by A. pullulans with Ca2+ added repeated batch culture

Cao

Chen

Luo

et al. 2016

International Journal of Biological Macromolecules

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β-Poly(malic acid) (PMLA) has attracted increasing attentions because of its potential application in medicine and other industries. In this study, the variation of PMLA molecular weight (Mw) in the batch culture and the strategies to enhance PMLA Mw were studied. Adding exogenous Ca(2+) (0.1g/L CaCl2) to the medium caused a significant increase in both PMLA concentration and Mw (11.38% and 26.3%, respectively) when Na2CO3 was used as the neutralizer. The Mw of PMLA during the process of batch culture, which associated with the specific PMLA production per unit cell mass (Yp/x) before glucose was depleted, increased from 12.522 KDa to its maximum 18.693 KDa and then kept decreasing until the end of the culture. Compared with the results in batch culture, Mw increased by 84.4% (up to 19.51 kDa) with a productivity of 1.1 gh(-1)L(-1) when the cells were maintained in exponential growth phase during Ca(2+) added repeated batch culture. The present work provides an efficient approach to obtain superior quality PMLA product with high Mw.

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Effect of exogenous calcium on morphological development and biopolymer synthesis in the fungus Aureobasidium pullulans

Cited by 13 publications

References 22 publications

Effect of carbon source on polysaccharide production by alginate‐entrapped Aureobasidium pullulans ATCC 42023 cells

Effect of carbon source on polysaccharide production by alginate‐entrapped Aureobasidium pullulans ATCC 42023 cells

Liquid films on shake flask walls explain increasing maximum oxygen transfer capacities with elevating viscosity

High molecular weight β-poly(l-malic acid) produced by A. pullulans with Ca2+ added repeated batch culture

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