Production of β-glucosidase, exo-β-l,4-glucanase and endo-³-l,4-glucanase by selected microscopic fungi

Augustín, Jozef; Zemek, J.; Kuniak, Ľ.; Fassatiová, O.

doi:10.1007/bf02927217

Cited by 4 publications

(2 citation statements)

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“…Some studies have shown that pullulan is produced more in stationary, compared to exponential-phase, growth. , This is consistent with the idea that pullulan is a secondary metabolite, and so it is produced only when growth decreases, although by a strict definition, secondary metabolites refer to diffusible products, and thus pullulan would not be such a compound. Other studies have shown that pullulan production is optimal during active cell growth or that synthesis is independent of biomass/growth . In our study, adhesion was greater in the earlier growth phase.…”

Section: Discussionsupporting

confidence: 59%

“…Other studies have shown that pullulan production is optimal during active cell growth 58 or that synthesis is independent of biomass/growth. 59 In our study, adhesion was greater in the earlier growth phase. We could suppose that it is advantageous for the microbe to adhere in order to gain nutrients or to seek protection from predators in the aqueous suspension, but these ideas are very speculative at this time.…”

Section: Discussionsupporting

confidence: 47%

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Adhesion of Aureobasidium pullulans Is Controlled by Uronic Acid Based Polymers and Pullulan

et al. 2005

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Aureobasidium pullulans is a potentially pathogenic microfungus that produces and secretes the polysaccharide pullulan and other biomacromolecules, depending on the microbe's physiological state. The role of these macromolecules in mediating adhesion and attachment were examined. Interfacial forces and adhesion affinities of A. pullulans were probed for early-exponential phase (EEP) and late-exponential phase (LEP) cells, using atomic force microscopy (AFM). Biochemical assays showed that A. pullulans produces both pullulan and a uronic acid based polymer. The pullulan is not produced until the LEP, and it can be removed by treatment with pullulanase. Both adhesion forces between the microbe and the AFM tip (silicon nitride) and attachment of the cells to quartz sand grains were controlled by the density of the uronic acid polymer. Uronic acid polymers doubled in density between the EEP and the LEP and were unaffected by the enzyme pullulanase. Retention to quartz in a packed column was quantified using the collision efficiency (R), the fraction of collisions between the microbes, and the sand grains, that result in attachment. Adhesion forces and retention on glass were well correlated, with these values being higher for EEP cells (F adh ) 7.65 ( 4.67 nN; R ) 1.15) than LEP (F adh ) 2.94 ( 0.75; R ) 0.49) and LEP + pullulanase cells (F adh ) 2.33 ( 2.01 nN; R ) 0.43). Steric interactions alone do not describe the adhesion behavior of this fungus, but they do provide information regarding the length and density of the macromolecules studied.

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