Enzyme-Catalyzed Production of Potato Galactan-Oligosaccharides and Its Optimization by Response Surface Methodology

Abstract

This work shows an optimized enzymatic hydrolysis of high molecular weight potato galactan yielding pectic galactan-oligosaccharides (PGOs), where endo-β-1,4-galactanase (galactanase) from Cellvibrio japonicus and Clostridium thermocellum was used. For this, response surface methodology (RSM) by central composite design (CCD) was applied. The parameters varied were temperature (°C), pH, incubation time (min), and enzyme/substrate ratio (U/mg). The optimized conditions for the production of low degree of polymerization (DP) PGOs were obtained for each enzyme by spectrophotometric assay and confirmed by chromatography. The optimal conditions predicted for the use of C. japonicus galactanase to obtain PGOs of DP = 2 were T = 51.8 °C, pH 5, E/S = 0.508 U/mg, and t = 77.5 min. For DP = 3, they were T = 21 °C, pH 9, E/S = 0.484 U/mg, and t = 12.5 min; and for DP = 4, they were T = 21 °C, pH 5, E/S = 0.462 U/mg, and t = 12.5 min. The efficiency results were 51.3% for substrate hydrolysis. C. thermocellum galactanase had a lower yield (35.7%) and optimized conditions predicted for PGOs of DP = 2 were T = 60 °C, pH 5, E/S = 0.525 U/mg, and time = 148 min; DP = 3 were T = 59.7 °C, pH 5, E/S = 0.506 U/mg, and time = 12.5 min; and DP = 4, were T = 34.5 °C, pH 11, E/S = 0.525 U/mg, and time = 222.5 min. Fourier transformed infrared (FT-IR) and nuclear magnetic resonance (NMR) characterizations of PGOs are presented.

NVCL-Based Galacto-Functionalized and Thermosensitive Nanogels with GNRDs for Chemo/Photothermal-Therapy

“…CDDP and DOX were tested since those agents are widely used in chemotherapy while being very different: one organic molecule (DOX) and one metal-based inorganic compound. Additionally, the galactose linking onto the nanogels can provide the target-specific property by improving the interaction between the nanoparticles and specific receptors of tumor cells [ 28 , 29 ]. In this investigation, two types of experiments were carried out: first, CDDP or DOX were loaded into selected nanogels, and then in vitro release was evaluated under conditions that mimic a healthy (pH 7.4 and 37 °C) and cancerous (pH 6 and 40 °C) tissue.…”

Cytotoxicity activities and chemical characteristics of exopolysaccharides and intracellular polysaccharides of Physarum polycephalum microplasmodia

“…This similarity, in fact, was consistent with the result of a monosaccharide analysis, which pointed out that glucose was the main component (86.46%) of the IPS, whereas for EPS it was galactose (80.22%). However, the EPS might be not related to galactan chains because when compared with the IR spectrum of potato pectic galactan, no similar characteristic was observed [ 35 ]. In addition, based on the data shown in Table 2 , it would be anticipated that the presence of a large amount of unknown components in the samples might have caused some interference to the FTIR recorded spectra of the EPS samples.…”