Amyloglucosidase Research Articles

Screening of oleaginous yeast for lipid production using rice residue from food waste as a carbon source

Rice residue from food waste contained of starch as a mainly component which could be either hydrolyzed to be fermentable sugars or directly used as a carbon source for the growth and high value metabolites production by various microorganisms. Therefore, this study focused on the utilization of rice residue and rice residue hydrolysate from food waste as a carbon source for the growth and lipids production of oleaginous yeast. Rice residue obtained from canteen of the Faculty of Agro-Industry, Chiang Mai University, Thailand. It composed of moisture content (76.68±0.55%), crude fat (1.76±0.47%), crude protein (3.04±0.06%), ash content (0.46±0.07%), and carbohydrate content (18.05±0.01%), respectively. Rice residue was then subjected to enzymatic hydrolysis using α-amylase and amyloglucosidase (AMG), resulting the maximal reducing sugars of 168.02±0.02 g/L. The screening of oleaginous yeast from flowers and leaves samples from Doi-Inthanon National Park, Faculty of Agro-Industry, Chiang Mai University, the culture collection of the Thailand Institute of Scientific and Technological Research (TISTR) and the Division of Biotechnology, Faculty of Agro-Industry, Chiang Mai University were investigated. Sixty-seven isolates were obtained, and only four isolates were identified as oleaginous yeast because of containing high lipids content more than 20% (w/w), when glucose or rice residue hydrolysate was used as a carbon source. Those oleaginous yeasts were identified as Rhodotorula sp. C7, Rhodosporidium paludigenum C10, and the new isolate TC32, respectively. Their growths and lipid productions were compared with Diozegia sp. TISTR5792. The results showed that, C7, C10, TISTR5792 and TC32 produced the maximal lipids content of 24.26±0.56, 23.69±0.91, 22.43±1.09 and 23.07±0.80% (w/w) when cultivated in the basal medium supplemented with enzymatic-rice residue hydrolysate. Surprisingly, we found that TISTR5792 and TC32 could grow well in the medium supplemented with rice residue > (without hydrolysis) and showed lipids content of 18.41±0.10 and 21.67±0.02% (w/w), respectively. These results indicated that rice residue from food waste shows a high potential to be an effective carbon source for the growth and lipid production of the selected oleaginous yeasts.

Ethanol Production From Cassava Wastes (Pulp And Peel) Using Alcohol Tolerant Yeast Isolated From Palm Wine

Introduction: The efficient ethanol production using Saccharomyces spp. isolated from palm wine in utilizing industrial wastes (cassava pulp and peel) was studied in the liquid state fermentation process. Methods: The percentage alcohol in the cassava pulp and peel was obtained by digesting the cassava waste with three different commercial exogenous enzymes which include alpha amylase (Termamyl), Amyloglucosidase (AMG), β-glucanase t a-amylase (Cereflo) and fermenting with yeast ( Saccharomyces spp.) isolated from palm wine. The combination of two enzymes in starch hydrolysis produced more sugars than individual enzyme usage and also yielded more of ethanol when compared to a single enzyme activity. It was also observed that AMG combined with Termamyl yielded 2.05% ethanol. Cereflo combined with Termamyl yielded 1.6% ethanol while Tennamyl alone yielded 1.26% ethanol from cassava pulp. However, it was also observed that AMG combined with Termamyl yielded 0.46% ethanol, Cereflo combined with Termamyl yielded 0.73% ethanol while Termamyl alone yielded 0.33% ethanol from cassava peel. Results: This implies that ethanol produced from cassava pulp is higher than ethanol produced from cassava peel, since the cassava pulp contains high starch than the peel. Conclusions: These digestions using these enzymes and subsequent ethanol production can go a long way in waste management for economic purposes.

Characterization and Application of BiLA, a Psychrophilic α-Amylase from Bifidobacterium longum.

In this study, a novel α-amylase was cloned from Bifidobacterium longum and named BiLA. The enzyme exhibited optimal activity at 20 °C and a pH value of 5.0. Kinetic analysis using various carbohydrate substrates revealed that BiLA had the highest k(cat/)K(m) value for amylose. Interestingly, analysis of the enzymatic reaction products demonstrated that BiLA specifically catalyzed the hydrolysis of oligosaccharides and starches up to G5 from the nonreducing ends. To determine whether BiLA can be used to generate slowly digestible starch (SDS), starch was treated with BiLA, and the kinetic parameters were analyzed using porcine pancreatic α-amylase (PPA) and amyloglucosidase (AMG). Compared to normal starch, BiLA-treated starch showed lower k(cat)/K(m) values with PPA and AMG, suggesting that BiLA is a potential candidate for the production of SDS.

Replacement of Yolk of the Chicken Embryoin ovowith Fresh Yolk or Yolk Varying in Granule and Cholesterol Content

A method has been devised to study the nutritional role of yolk cholesterol in the development of the chicken ( Gallus gallus domesticus) embryo using egg yolk replacement. Preliminary experiments revealed that 11 mL of yolk in medium-sized eggs were adequate to support embryos from 4 to 20 days of incubation, and that low levels of β-cyclodextrin (β-CD) and amyloglucosidase (AG) in yolk were tolerated by the embryo. Fresh egg yolk was treated with β-CD at 50 °C, centrifuged to remove the insoluble β-CD-cholesterol complex, and incubated with AG to degrade residual β-CD. The cholesterol content was reduced from 13.1 mg g−1in fresh egg yolk to 1.3 mg g−1in cholesterol-reduced yolk supernatant (CRYS). Yolk granules co-precipitated with the β-CD-cholesterol complex. The cholesterol concentration of CRYS supplemented with granules from fresh yolk ( i.e. CRYSg) was 3.2 mg g−1. When yolks of early 5-day embryos were replaced with 11 mL of CRYS, the maximum survival was 17 days of incubation. When yolks were replaced with 11 mL CRYSg, 30% of embryos survived to 20 days, a significant increase in survival compared to CRYS ( P < 0.05). Sixty per cent of embryos receiving fresh yolk (yolk controls) and 83% of embryos in intact eggs (intact controls) survived to 20 days. The controls did not differ significantly ( P > 0.05). Embryos in the CRYS and CRYSg groups had shorter survivals than yolk controls ( P < 0.001) and intact controls ( P < 0.005). These results suggest a methodological approach for investigations of egg yolk cholesterol and yolk granules in chick embryo development.

Solid state fermentation with recovery of Amyloglucosidase from extract by direct immobilization in cross linked enzyme aggregate for starch hydrolysis

Abstract Main limitations in application of Amyloglucosidase (AMG), an important industrial enzyme for starch hydrolysis, areits high production cost and limited reusability. Immobilization techniques have been tried to address the issue of reusability, however, these techniques either increase the cost of enzyme o rare difficult to scale up owing to special requirements for synthesis of carriers. We tried to address the issue of production cost and reusability for enzyme application by forming carrier free cross-linked enzyme aggregate (CLEA) of AMG from crude SSF extract of Aspergillus niger . CLEA recovered 65 percent activity from extract and retained 90% even after 25 cycles of reuse. CLEA showed improved affinity toward substrate; higher storage, thermal and pH stability. Use of cheap SSF and direct immobilization of AMG from extract can reduce the cost of starch hydrolysis.

Simultaneous saccharification and fermentation of cassava waste for ethanol production

The efficiency of enzymatic and microbial saccharification of cassava waste for ethanol production was investigated and the effective parameters were optimized. The mixture of amylase and amyloglucosidase (AMG) resulted in a significantly higher rate of saccharification (79.6%) than the amylase alone (68.7%). Simultaneous saccharification and fermentation (SSF) yielded 6.2 g L-1 ethanol representing 64.5% of the theoretical yield. Saccharification and fermentation using pure and co-cultures of fungal isolates including Rhizopus stolonifer, Aspergillus terreus, Saccharomyces diastaticus and Zymomonas mobilis revealed that the co-culture system involving S. diastaticus and Z. mobilis was highly suitable for the bio-conversion of cassava waste into ethanol, resulting in 20.4 g L-1 in 36 h (91.3% of the theoretical yield).

Alanine Functionalized Magnetic Nanoparticles for Reversible Amyloglucosidase Immobilization

A hydrophobic group/comonomer N-methacryloyl-(l)-alanine (MAAL) containing 2-hydroxyethyl methacrylate (HEMA)-based magnetic hydrophobic nanoparticles was synthesized by using a microemulsion polymerization technique for immobilization of amyloglucosidase (AMG). The magnetic hydrophobic nanoparticles with an average diameter of 79 nm were characterized with Fourier transform infrared spectroscopy, transmission electron microscopy, zeta-size analysis, and electron spin resonance spectroscopy. Hereby, the effecting factors such as initial concentration of AMG, pH, and temperature on the immobilization were investigated. After determining the optimum immobilization conditions, the kinetic constants (KM and Vmax) and properties of free and immobilized AMG were investigated in batch studies. The maximum AMG adsorption capacity of the magnetic hydrophobic nanoparticles was 294.42 mg/g at pH 3.0. The optimum pH and temperature for free and immobilized AMG were found to be pH 5.0 and 60 °C. The KM value for immob...

Assessment of amyloglucosidase activity during production and storage of laminated pie dough. Impact on raw dough properties and sweetness after baking

Amyloglucosidase (AMG) is an enzyme that hydrolyzes starch into glucose units. AMG activity was tested in a model pie dough during the dough-making process (after mixing and sheeting) and during storage for 4 weeks at 4 °C. The activity was quantified by measuring the glucose content of dough and baked products using HPLC. The consequences of AMG activity on the sweet taste of the baked products (sensory ranking test) and on the rheological properties of the dough were studied and compared with a control dough formulated with sucrose. The results showed a significant production of glucose during the dough-making process and during baking when AMG was used. During the dough-making process, AMG activity was limited by the substrate. During baking, the substrate was no longer a limiting factor and the amount of glucose released was directly proportional to the amount of AMG used. The mixing time was increased and the elastic properties of the dough decreased when AMG was added. However, these impacts of AMG on dough properties were not as significant as those of sucrose addition. Addition of 0.75% AMG (flour basis) developed a sweet taste equivalent to that obtained by addition of 17% sucrose (flour basis).

Modification to AOAC official methods 2009.01 and 2011.25 to allow for minor overestimation of low molecular weight soluble dietary fiber in samples containing starch.

AOAC Official Methods 2009.01 and 2011.25 have been modified to allow removal of resistant maltodextrins produced on hydrolysis of various starches by the combination of pancreatic alpha-amylase and amyloglucosidase (AMG) used in these assay procedures. The major resistant maltodextrin, 6(3),6(5)-di-alpha-D-glucosyl maltopentaose, is highly resistant to hydrolysis by microbial alpha-glucosidases, isoamylase, pullulanase, pancreatic, bacterial and fungal alpha-amylase and AMG. However, this oligosaccharide is hydrolyzed by the mucosal alpha-glucosidase complex of the pig small intestine (which is similar to the human small intestine), and thus must be removed in the analytical procedure. Hydrolysis of these oligosaccharides has been by incubation with a high concentration of a purified AMG at 60 degrees C. This incubation results in no hydrolysis or loss of other resistant oligosaccharides such as FOS, GOS, XOS, resistant maltodextrins (e.g., Fibersol 2) or polydextrose. The effect of this additional incubation with AMG on the measured level of low molecular weight soluble dietary fiber (SDFS) and of total dietary fiber in a broad range of samples is reported. Results from this study demonstrate that the proposed modification can be used with confidence in the measurement of dietary fiber.

Slower in vivo glucogenesis from starch oligomers by mucosal sucrase‐isomaltase (1039.8)

While luminal α‐Amylase (AMY) is recognized as a starch digesting enzyme, the products require that glucose be hydrolyzed from the non‐reducing ends of the oligosaccharide produced. Two mucosal enzyme complexes are required for glucogenesis: Maltase‐glucoamylase (Mgam) is a fast and Sucrase‐isomaltase (Si) is a slow α‐glucosidase. Mgam was knocked‐out in mice with the objective of determining role of Si on in vivo starch digestion to glucose. 8 mice were fed 0.5 gm. of chow containing normal maize starch. 2 h after feeding they were euthanized and 4 segments of small bowel (SB) snap‐frozen. The segments were thawed and homogenized in water. Protein assays were by Bradford method. The homogenate was denatured in 80% ethanol at 80°C. Supernatant was collected by centrifugation. Free glucose of concentrated supernatant was determined by glucose oxidase/peroxidase. Soluble oligosaccharides were determined by diluting supernatant with buffer, pH 4.5, in 10% ethanol and 2.5 units of amyloglucosidase (AMG) added. Free glucose was assayed as above. Residual starch was assayed as glucose after hydrolysis to glucose of the gelatinized precipitate in 90% DMSO by the AMG/AMY method. Fractions were summed as total carbohydrate (CHO). All Assays were in triplicate. At 2 h wild type (WT) mice had a peak of residual starch in the distal jejunum (DJ); peak of oligomers in the proximal ilium (PI); and very little total CHO in the distal ilium (DI). Mgam nulls had significantly increased residual starch and total CHO in DI. When expressed as oligomers/starch there was significant accumulation in null DI. Compared with nulls, the free glucose/oligomers in WT was significantly increased in proximal Jejunum, PI, and DI. In conclusion, at 2 h after starch feeding the slower remaining Si activity of Mgam null can produce free glucose but precursor oligomers accumulate in DI and the total SB in vivo glucose production is significantly reduced compared to WT mice.Grant Funding Source: USDA ARS

Functionality of porous starch obtained by amylase or amyloglucosidase treatments

Porous starch is attracting very much attention for its absorption and shielding ability in many food applications. The effect of two different enzymes, fungal α-amylase (AM) or amyloglucosidase (AMG), on corn starch at sub-gelatinization temperature was studied as an alternative to obtain porous starch. Biochemical features, thermal and structural analyses of treated starches were studied. Microscopic analysis of the granules confirmed the enzymatic modification of the starches obtaining porous structures with more agglomerates in the case of AMG treated starches. Several changes in thermal properties and hydrolysis kinetics were observed in enzymatically modified starches. Hydration properties were significantly affected by enzymatic modification being greater influenced by AMG activity, and the opposite trend was observed in the pasting properties. Overall, results showed that enzymatic modification at sub-gelatinization temperatures really offer an attractive alternative for obtaining porous starch granules to be used in a variety of foods applications.

Immobilization of amyloglucosidase from SSF of Aspergillus niger by crosslinked enzyme aggregate onto magnetic nanoparticles using minimum amount of carrier and characterizations

• Amyloglucosidase from solid state fermentation extracts was directly immobilized. • Crosslinked enzyme aggregate onto magnetic nanoparticles was prepared. • High recovery (∼93% activity) into immobilized enzyme using 14 times less carrier. • Immobilized enzyme showed enhanced substrate affinity, stability, reusability. • Procedure expected to reduce the cost of starch hydrolysis process. Immobilizations of enzymes are done for operational stability, recovery and re-use of the enzymes and easy separation of products. Amyloglucosidase (AMG) obtained from solid state fermentation (SSF) of Aspergillus niger was directly immobilized by novel technique of crosslinked enzyme aggregate onto magnetic nanoparticles. AMG was covalently linked to the magnetic nanoparticle (MNP) to form a monolayer of AMG (MNP–AMG), followed by crosslinked aggregates with free AMG (which was not immobilized) to yield MNP with high enzyme loading (MNP–AMG n ). Under optimized conditions, very high recovery (92.8%) of enzyme activity was obtained in MNP–AMG n using 14 times less carrier compared to the quantity of carrier required by conventional method. MNP–AMG n showed enhanced affinity for substrate, thermal stability, storage stability and reusability.

Aqueous two-phase poly(ethylene glycol)–sodium polyacrylate system for amyloglucosidase purification: Equilibrium diagrams and partitioning studies

Extraction and purification of amyloglucosidase (AMG) using aqueous two phase systems (ATPSs) composed by polyethylene glycol (PEG, average molar mass of 4000g/mol) and sodium polyacrylate (NaPA, average molar mass of 15,000g/mol) has been studied. Phase equilibrium diagrams were obtained at pH 6.0 and 9.0, which were used for partitioning studies. The selectivity (S) and partition coefficient (Ke) of AMG were evaluated as a function of pH, temperature and concentration of PEG and NaPA, and it was found that these parameters were affected by pH and NaPA concentrations. A face-centered design with the response surface methodology was applied for selectivity optimization. The highest value found for S was 1.6 at pH of 6.5, temperature of 25°C, PEG concentration of 12.5% (w/w) and NaPA concentration of 11.4% (w/w). The corresponding Ke was 2.0. The purification factor (PF) and the recovery yield (Y) were determined as 1.9% and 86%, respectively.

The ionic liquid isopropylammonium formate as a mobile phase modifier to improve protein stability during reversed phase liquid chromatography.

The room temperature ionic liquid isopropylammonium formate (IPAF) is studied as a reversed phase HPLC mobile phase modifier for separation of native proteins using a polymeric column and the protein stability is compared to that using acetonitrile (MeCN) as the standard organic mobile phase modifier. A variety of important proteins with different numbers of subunits are investigated, including non-subunit proteins: albumin, and amyloglucosidase (AMY); a two subunit protein: thyroglobulin (THY); and four subunit proteins: glutamate dehydrogenase (GDH) and lactate dehydrogenase (LDH). A significant enhancement in protein stability is observed in the chromatograms upon using IPAF as a mobile phase modifier. The first sharper peak at about 2min represented protein in primarily the native form and a second broader peak more retained at about 5-6min represented substantially denatured or possibly aggregated protein. The investigated proteins (except LDH) could maintain the native form within up to 50% IPAF, while a mobile phase, with as low as 10% MeCN, induced protein denaturation. The assay for pyruvate using LDH has further shown that enzymatic activity can be maintained up to 30% IPAF in water in contrast to no activity using 30% MeCN.

Ectopic expression of bacterial amylopullulanase enhances bioethanol production from maize grain

Heterologous expression of amylopullulanase in maize seeds leads to partial starch degradation into fermentable sugars, which enhances direct bioethanol production from maize grain. Utilization of maize in bioethanol industry in the United States reached ±13.3billion gallons in 2012, most of which was derived from maize grain. Starch hydrolysis for bioethanol industry requires the addition of thermostable alpha amylase and amyloglucosidase (AMG) enzymes to break down the α-1,4 and α-1,6 glucosidic bonds of starch that limits the cost effectiveness of the process on an industrial scale due to its high cost. Transgenic plants expressing a thermostable starch-degrading enzyme can overcome this problem by omitting the addition of exogenous enzymes during the starch hydrolysis process. In this study, we generated transgenic maize plants expressing an amylopullulanase (APU) enzyme from the bacterium Thermoanaerobacter thermohydrosulfuricus. A truncated version of the dual functional APU (TrAPU) that possesses both alpha amylase and pullulanase activities was produced in maize endosperm tissue using a seed-specific promoter of 27-kD gamma zein. A number of analyses were performed at 85°C, a temperature typically used for starch processing. Firstly, enzymatic assay and thin layer chromatography analysis showed direct starch hydrolysis into glucose. In addition, scanning electron microscopy illustrated porous and broken granules, suggesting starch autohydrolysis. Finally, bioethanol assay demonstrated that a 40.2±2.63% (14.7±0.90g ethanol per 100g seed) maize starch to ethanol conversion was achieved from the TrAPU seeds. Conversion efficiency was improved to reach 90.5% (33.1±0.66g ethanol per 100g seed) when commercial amyloglucosidase was added after direct hydrolysis of TrAPU maize seeds. Our results provide evidence that enzymes for starch hydrolysis can be produced in maize seeds to enhance bioethanol production.

Multi-pass high pressure homogenization of commercial enzymes: Effect on the activities of glucose oxidase, neutral protease and amyloglucosidase at different temperatures

This study evaluated the residual activities of amyloglucosidase (AMG) at 65 and 80 °C, glucose oxidase (GO) at 50 and 75 °C and neutral protease at 20 and 55 °C after 3 passes of high pressure homogenization (HPH) at 150 MPa and 200 MPa (neutral protease and AMG) and at 100 and 150 MPa (GO). The results for AMG and neutral protease showed that the improvement in maximum enzyme activity was reached after one pass at 200 MPa, with an increment in the AMG residual activity measured at 80 °C (activity increased from 13% to 21%) and in the neutral protease residual activity at 20 °C (activity increased from 50% to 64%). However, the multiple passes caused no improvement in the activities of the enzymes. To the contrary, the results obtained for GO showed that HPH at 150 MPa continuously improved the activity at 75 °C up to three passes, reaching an activity three times higher than the native sample. Additionally, it was observed that two passes of GO at 100 MPa resulted in the same level of GO activation reached after a single pass at 150 MPa. These results suggest that multiple HPH effects differ for each enzyme evaluated and can be applied to improve GO activity. Enzymes can be used in several areas of food industry. However, the price of enzymes and their low stability limits the enzymes' application in food industry. The HPH is suggested to process the enzyme prior to application, to increase enzyme activity mainly at non-ideal temperature. Therefore, the application of high pressure homogenization to improve enzymes activity can expand the range of enzyme uses.

Ethanol Production from Starch by Co-Immobilized Amyloglucosidase—Zymomonas Mobilis Cells in a Continuously-Stirred Bioreactor

ABSTRACTContinuous ethanol production from starch was studied in a continuously-stirred bioreactor using co-immobilized amyloglucosidase (AMG) and Zymomonas mobilis cells. In this process, saccharification of starch and fermentation to ethanol were carried out in a single reactor.The experiments were carried out at three sets of conditions for which temperature and centrifuged cell weight were 35°C and 20.3 g; 30°C and 19.0 g; 35°C and 29.2 g, respectively. The maximum volumetric ethanol productivity (7.6 g·L−1h−1) was achieved with 0.45 g·g−1 yield at the 0.20 h−1 dilution rate at 35°C, with the initial centrifuged cell concentration of 29.2 g. The maximum ethanol concentration (43.5 g L−1) was obtained at the 0.15 h−1 dilution rate with a 96 % conversion of substrate.When experimental conditions in the reactor were compared to each other, the initial concentration of immobilized cells was found to have a significant positive influence on the kinetic parameters of ethanol fermentation.

Iron Oxide Filled Magnetic Carbon Nanotube–Enzyme Conjugates for Recycling of Amyloglucosidase: Toward Useful Applications in Biofuel Production Process

Biofuels are fast advancing as a new research area to provide alternative sources of sustainable and clean energy. Recent advances in nanotechnology have sought to improve the efficiency of biofuel production, enhancing energy security. In this study, we have incorporated iron oxide nanoparticles into single-walled carbon nanotubes (SWCNTs) to produce magnetic single-walled carbon nanotubes (mSWCNTs). Our objective is to bridge both nanotechnology and biofuel production by immobilizing the enzyme, Amyloglucosidase (AMG), onto mSWCNTs using physical adsorption and covalent immobilization, with the aim of recycling the immobilized enzyme, toward useful applications in biofuel production processes. We have demonstrated that the enzyme retains a certain percentage of its catalytic efficiency (up to 40%) in starch prototype biomass hydrolysis when used repeatedly (up to ten cycles) after immobilization on mSWCNTs, since the nanotubes can be easily separated from the reaction mixture using a simple magnet. The enzyme loading, activity, and structural changes after immobilization onto mSWCNTs were also studied. In addition, we have demonstrated that the immobilized enzyme retains its activity when stored at 4 °C for at least one month. These results, combined with the unique intrinsic properties of the nanotubes, pave the way for greater efficiency in carbon nanotube-enzyme bioreactors and reduced capital costs in industrial enzyme systems.

Increasing fungi amyloglucosidase activity by high pressure homogenization

Abstract High pressure homogenization (HPH) was recently described as a process able to improve the activity of some enzymes; therefore, the HPH effects on amyloglucosidase (AMG) were investigated. Enzyme solution at pH 2.9, 4.3 and 6.5 were processed at pressures of 0 (just sample circulation on the equipment), 500, 1000, 1500 and 2000 bar and the HPH effects were determined through the enzyme residual activity measured at 35, 65 and 80 °C. Results at 35 °C showed no relative changes on AMG activity after HPH up to 2000 bar for the three evaluated pH. Similarly, at 65 °C (optimum temperature), native and homogenized enzyme at pH 2.9 and 6.5 showed no significant activity changes. On contrary, when enzyme was homogenized at pH 4.3 and its activity evaluated at optimum temperature, a significant activity increase (5–8%) was observed after homogenization at pressures of 1000 bar and above. At 80 °C, it was observed an AMG relative activity increase after HPH for the three evaluated pH. Sample homogenized at pH 2.9 showed a gradual and significant activity increase, reaching a maximum increment of 100% after homogenization at 2000 bar with reference to the native enzyme. At pH 4.3 and 6.5, homogenization up to 1000 bar resulted on a significant AMG activity increase of around 20 and 30%, respectively. Therefore, the results highlighted that HPH can increase AMG activity, being dependent on the pH of enzyme solution and the applied pressure. Also, it was observed that process can change the AMG activity at different temperatures, being especially interesting when AMG activity at high temperature is required. Industrial relevance Two important application of amyloglucosidase are the starch saccharification to obtain corn syrup and the use in juice processing aiming to prevent turbidity and viscosity enhancement caused by unripe fruit. The HPH is suggested to process the enzyme prior to application, to increase its activity at high temperature with consequent time and energy economy during saccharification process. Also HPH is a promising non thermal methodology applied to stabilize juices microbiologically and physically, through particle size reduction and the high stability of amyloglucosidase during HPH process can be important to guarantee the effectiveness of amyloglucosidase during and after HPH.

Study of the covalently immobilized amyloglucosidase on macroporous polymer by mathematical modeling of the pH optima

BACKGROUND: A totally new approach has been applied for mathematical modeling of the enzyme activity/pH relationship, for quantification and distribution of enzyme activity in and out of carrier pores. This is a very simple and elegant method for determination of the distribution of enzyme molecules on the surface and inside the particles, simply through measurement of enzyme activity at different pH values. RESULTS: Amyloglucosidase (AG) from Aspergillus niger was covalently immobilized onto poly(GMA-co-EGDMA) by the glutaraldehyde and periodate methods. Mathematical modeling of the pH optima for two types of covalently immobilized AG resulted in higher enzyme amounts on the surface within periodate immobilizate (67%) in comparison with glutaraldehyde immobilizate (53%). These values are modified to 64.25% for periodate immobilizate and 49.95% for glutaraldehyde immobilizate when diffusion effects are taken into account. CONCLUSION: The mathematical model applied enabled observation of the difference between the two types of coupling agents and different immobilization procedures throughout quantification of the immobilized enzyme on the matrix surface and inside pores. Copyright © 2012 Society of Chemical Industry