Purified chitin-glucan complex (CGCpure) was extracted from Komagataella pastoris biomass using a hot alkaline treatment, followed by neutralization and repeated washing with deionized water. The co-polymer thus obtained had a β-glucan:chitin molar ratio of 75:25 and low protein and inorganic salts contents (3.0 and 0.9 wt%, respectively). CGCpure had an average molecular weight of 4.9 × 10(5)Da with a polydispersity index of 1.7, and a crystallinity index of 50%. Solid-state NMR provided structural insight at the co-polymer. X-ray diffraction suggests that CGCpure has α-chitin in its structure. CGCpure presented an endothermic decomposition peak at 315°C, assigned to the degradation of the saccharide structures. This study revealed that K. pastoris CGC has properties similar to other chitinous biopolymers and may represent an attractive alternative to crustacean chitin derived-products, being a reliable raw material for the development of new/improved pharmaceutical, cosmetic or food products.

structural analysis, molecular weight, chitin–glucan complex (CGC), Komagataella pastoris, thermal properties

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
2	Ac	172.8	22.9
	bDGlcpN	103.5	55.0	74.2-76.4	85.7	74.2-76.4	62.0


1H NMR data:
missing...

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

*O[C@@H]1[C@@H](CO)O[C@@H](*)[C@H](NC(C)=O)[C@H]1O

203.194 g/mol (C₈H₁₃R₂NO₅, R = next and previous repeats, not counted in mol weight)

Purified chitin-glucan complex (CGCpure) was extracted from Komagataella pastoris biomass using a hot alkaline treatment, followed by neutralization and repeated washing with deionized water. The co-polymer thus obtained had a β-glucan:chitin molar ratio of 75:25 and low protein and inorganic salts contents (3.0 and 0.9 wt%, respectively). CGCpure had an average molecular weight of 4.9 × 10(5)Da with a polydispersity index of 1.7, and a crystallinity index of 50%. Solid-state NMR provided structural insight at the co-polymer. X-ray diffraction suggests that CGCpure has α-chitin in its structure. CGCpure presented an endothermic decomposition peak at 315°C, assigned to the degradation of the saccharide structures. This study revealed that K. pastoris CGC has properties similar to other chitinous biopolymers and may represent an attractive alternative to crustacean chitin derived-products, being a reliable raw material for the development of new/improved pharmaceutical, cosmetic or food products.

structural analysis, molecular weight, chitin–glucan complex (CGC), Komagataella pastoris, thermal properties

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
	bDGlcp	103.5	74.2-76.4	85.7	68.5	74.2-76.4	62.0


1H NMR data:
missing...

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

[*]O[C@@H]1[C@@H](O)[C@H]([*])O[C@H](CO)[C@H]1O

162.141 g/mol (C₆H₁₀R₂O₅, R = next and previous repeats, not counted in mol weight)

Enzymatic degradation of guar galactomannan is studied using gel permeation chromatography (GPC) and steady shear viscometry. In very dilute polymer solutions, reaction rate increases with first-order kinetics with substrate concentration. In the intermediate concentration regime, the enzyme/polymer binding saturates, and the degradation kinetics is zero-order. The observations are in accord with a Michaelis-Menton kinetics model. The Michaelis-Menton parameter, Km and Vmax, were determined to be 0.6 mM and 0.78 nmol/(mL s) for guar at pH = 7, where the maximal velocity of the reaction, Vmax, was measured in terms of the molar concentration of glycosidic bonds broken per unit time. However, as the solution increases in concentration, the reaction rate decreases and the enzyme diffusion through the concentrated polymer gel becomes a limiting factor. A reaction-diffusion model is presented to express the competition between enzyme reaction and diffusion. The scaling theory and kinetic data are used to define the boundaries of the polymer concentration regimes between substrate (i.e., polymer strand) limited reactions, enzyme limited reactions, and hindered diffusion limited reactions. The influence of polymer derivatization on the degradation kinetics was also explored. The degradation rate was shown to be greatly affected by the type of substituent groups as well as the degree of substitution. The triggering mechanism and controlled degradation were found for the enzymatic hydrolysis of cationically derivatized guar solutions.

Galactomannan, enzymatic degradation, guar gum

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

[*]O[C@@H]1[C@@H](CO)O[C@@H](O[C@@H]2[C@@H](CO[C@H]3O[C@H](CO)[C@H](O)[C@H](O)[C@H]3O)O[C@@H](O[C@@H]3[C@@H](CO)O[C@@H](O[C@@H]4[C@@H](CO[C@H]5O[C@H](CO)[C@H](O)[C@H](O)[C@H]5O)O[C@@H](O[C@@H]5[C@@H](CO)O[C@@H]([*])[C@@H](O)[C@H]5O)[C@@H](O)[C@H]4O)[C@@H](O)[C@H]3O)[C@@H](O)[C@H]2O)[C@@H](O)[C@H]1O

1134.987 g/mol (C₄₂H₇₀R₂O₃₅, R = next and previous repeats, not counted in mol weight)