Pretreatment Enzymatic Hydrolysis Research Articles

Sequential Enzymatic Hydrolysis and Ultrasound Pretreatment of Pork Liver for the Generation of Bioactive and Taste-Related Hydrolyzates.

In the study of protein-rich byproducts, enzymatic hydrolysis stands as a prominent technique, generating bioactive peptides. Combining exo- and endopeptidases could enhance both biological and sensory properties. Ultrasound pretreatment is one of the most promising techniques for the optimization of enzymatic hydrolysis. This research aimed to create tasteful and biologically active pork liver hydrolyzates by using sequential hydrolysis with two types of enzymes and two types of ultrasound pretreatments. Sequential hydrolyzates exhibited a higher degree of hydrolysis than single ones. Protana Prime hydrolyzates yielded the largest amount of taste-related amino acids, enhancing sweet, bittersweet, and umami amino acids according to the Taste Activity Value (TAV). These hydrolyzates also displayed significantly higher antioxidant activity. Among sequential hydrolyzates, Flavourzyme and Protana Prime hydrolyzates pretreated with ultrasound showed the highest ferrous ion chelating activity. Overall, employing both Alcalase and Protana Prime on porcine livers pretreated with ultrasound proved to be highly effective in obtaining potentially tasteful and biologically active hydrolyzates.

A sustainable bio-circular way for biorefinery of rice straw into bioproducts based on energy-efficient pretreatment

Lignocellulosic biorefinery faces challenges associated with high energy input during pretreatment and high enzyme cost for enzymatic hydrolysis of cellulose, as well as the intricate valorization of lignin and hemicellulose. This study applied KOH-urea pretreatment to obtain maximum lignin removal of 68.93 % from rice straw at 80 °C for 60 min. The pretreatment consumed only 10.49 % of the total energy input. Five-time dilution of neutral black liquor can optimally stimulate the plant growth. Enzymatic conversion of KOH-urea-treated rice straw attained 92.02 % at 20 % solid concentration with 10 FPU cellulase/g substrate. The ethanol concentration achieved 37.02 g/L at a yield of 75.89 %. The solid residue after fermentation contained 42.40 % dietary fiber and 16.70 % protein, which is suitable as animal feed. This study developed a simple bio-circular way to concurrently produce liquid fertilizer, bioethanol, and animal feed from rice straw.

Comprehensive Analysis of Physicochemical Properties and Volatile Compounds in Different Strawberry Wines under Various Pre-Treatments.

Pre-fermentation treatment has an important impact on the color, aroma, taste, and other characteristics of fruit wine. To discover suitable pre-treatment techniques and conditions that yield strawberry wine of excellent quality, the influences of juice fermentation, pulp maceration, thermovinification, and enzymatic hydrolysis pre-treatments on the basic chemical composition, color, antioxidant capacity, and volatile organic compounds in strawberry wines were investigated. The results showed that the color, antioxidant properties, and volatile aroma of strawberry wines fermented with juice were different from those with pulp. Strawberry wines fermented from juice after 50 °C maceration had more desirable qualities, such as less methanol content (72.43 ± 2.14 mg/L) compared with pulp-fermented wines (88.16 ± 7.52 mg/L) and enzymatic maceration wines (136.72 ± 11.5 mg/L); higher total phenolic content (21.78%) and total flavonoid content (13.02%); enhanced DPPH (17.36%) and ABTS (27.55%) free radical scavenging activities; richer essential terpenoids and fatty acid ethyl esters, such as linalool (11.28%), ethyl hexanoate (14.41%), ethyl octanoate (17.12%), ethyl decanoate (32.49%), and ethyl 9-decenoate (60.64%); pleasant floral and fruity notes compared with juice-fermented wines macerated at normal temperatures; and a lighter color. Overall, juice thermovinification at 50 °C is a potential pre-treatment technique to enhance the nutrition and aroma of strawberry wine.

Optimising chemo-enzymatic separation of polyester cellulose blends

The study demonstrates the potential of enzymatic hydrolysis and alkaline pretreatment for sustainable blended textile recycling. The target is complete cellulose removal while preserving the polyester integrity for recovery. Interactions of sodium hydroxide concentration (10 %–30 %), urea concentration (0 %–12 %), and temperature (-20 °C–50 °C) were investigated during pretreatment using a design of experiments. Analysis revealed a bimodal pattern in polyester mass loss, with one peak at lower concentrations and temperatures, and a more prominent peak at higher concentrations and temperatures. Cellulose hydrolysis also occurred under high NaOH concentrations and elevated temperatures (50 °C, 30 % NaOH, 0 % urea). Optimal conditions, preserving polyester integrity while achieving complete cellulose elimination, were identified at temperatures between 6.2 °C and 13.3 °C, with NaOH concentrations of 20.7 %–26.6 % (0 % urea) or 13.9 % NaOH and 12 % urea. These findings pave the way for a greener, more efficient textile recycling, advancing the circularity for textiles.

Optimization of Microwave-Assisted Organosolv Pretreatment for Enzymatic Hydrolysis of Cherry Tree Pruning and Pistachio Shells: a Step to Bioethanol Production

The overall purpose of this research work was to apply a microwave-assisted digestion process combined with ethanol organosolv as pretreatment for pistachio shells (PS) and cherry tree pruning (CTP) biomasses for cellulose production. This process would reduce the technical and environmental disadvantages of the accumulation of these agricultural wastes. A central composite design based on the Response Surface Methodology was applied to check the effect of reaction time, temperature, and concentration of ethanol acid solution. Adequate models have been obtained for the contents of cellulose and lignin of the treated solids as well as for solubilized cellulose percentage. Best conditions implied 67% ethanol and 30 min at 150 ∘\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$~\\mathrm {^\\circ }$$\\end{document}C, involving the production of a cellulose-enriched material (81.1% and 90.1% for treated CTP and PS, respectively). Finally, enzymatic hydrolysis of these materials was carried out, reaching glucose concentrations of 70 and 100 kg/m3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{3}$$\\end{document} for CTP and PS, resulting in enzymatic hydrolysis yields at 12 h of 97.2% and 76.9%. These high values are one of the main novelties and strengths of this work, as show the ease of the process and can have a beneficial influence on its scale-up, reducing both costs and environmental impact.

Structural characterization of lignin-carbohydrate complexes from Chinese quince fruits extracted after enzymatic hydrolysis pretreatment

Chinese quince fruit (CQF) contains abundant pectin; however, the pectin cannot be efficiently separated by conventional approaches because of strong lignin-carbohydrate complexes (LCC). In this study, to elucidate the structural characteristics of the original LCC formed by lignin and pectin in CQF, single and multiple enzymatic hydrolysis pretreatments were innovatively performed, and the resulting LCC preparations were comprehensively characterized using a series of techniques. The enzymatic hydrolysis pretreatments significantly increase the LCC yield, releasing LCC fractions with low molecular weights (Mw = 4660–8288 Da). LCC-4, isolated by pretreatment with cellulase plus xylanase, had the highest galacturonic acid content (15.5 %), followed by LCC-2 (isolated by xylanase pretreatment) of 14.0 %. In CQF, lignin develops lignin-carbohydrate (LC) bonds with pectin to form LCC, with phenyl-glycoside bond being the dominant linkage. Although the pectinase pretreatment reduced the pectin content, signals of the LC linkages in the 2D-HSQC spectra were enhanced. LCC-4 could be considered as the most representative of the original LCC in CQF due to its high pectin content and multiple LCC signals in the 2D-HSQC spectrum. The structural understanding of the original LCC in CQF will lay a foundation for designing appropriate methods for extracting pectin from CQF.

Kinetic Studies of Enzymatic Hydrolysis Pre-Treatment of Waste Bread Under Preliminary Conditions

This study investigate the process conditions of enzyme concentration (2.0, 4.0, 6.0% w/v), temperature (30, 40, 50 °C), and reaction time (0, 60, 90, 120, 180, 240 min) of enzymatic hydrolysis for sugar recovery from waste bread. The kinetics of the enzyme (α-amylase) was studied to analyse the chemical reaction and the activity of the α-amylase towards the starch present in the waste bread. Enzymatic hydrolysis with different substrate concentration (5, 10, 15, 20 g) was conducted to analyse the kinetics of the enzyme with increasing amount of substrate concentration. The highest reducing sugar yield from the waste bread was 119.73 mg/mL at 15g of substrate concentration, 6.0% w/v enzyme concentration, temperature 50°C and 180 mins reaction time. From this value, the percentage recovery of the reducing sugar was 71.84%. The Michaelis-Menten equation was applied to study the kinetics of enzymatic hydrolysis of waste bread. The Vmax value was 3443.234 µmol/L/min and the Km value was 6.0g.

Efficient production of ferulic acid and p-coumaric acid from reed straws via combined enzymatic hydrolysis and hydrothermal pretreatment

The present study aimed to evaluate an available process for production of ferulic acid (FA) and p-coumaric acid (pCA) that could be potentially used as functional agents in food processing. The hydrothermal pretreatment combined with enzymatic hydrolysis (HP-CEH) was explored for efficient production of phenolic acids from reed straws. The results indicated that HP-CEH significantly increased production of phenolic acids. The recovery yield of ferulic acid and p-coumaric acid was respectively found to be 0.69 and 0.81 mg/g dry reed straw when performed by HP-CEH for 16 h. The degradation of hemicellulose, lignocellulose and lignin, and disruption of cell walls or cellulose fibers contributed to phenolic acids production from reed straws. Moreover, the scavenging activity of hydroxyl radical and DPPH radical of the phenolic acids extracted by HP-CEH was respectively obtained to be 77.32% and 86.77%.

Effects of high-speed shear and double-enzymatic hydrolysis on the structural and physicochemical properties of rice porous starch

This study aimed to investigate the physicochemical properties of the rice porous starch (HSS-ES) prepared by high-speed shear combined with double-enzymatic (α-amylase and glucoamylase) hydrolysis, and to reveal their mechanism. The analyses of 1H NMR and amylose content showed that high-speed shear changed the molecular structure of starch and increased the amylose content (up to 20.42 ± 0.04 %). FTIR, XRD and SAXS spectra indicated that high-speed shear did not change the starch crystal configuration but caused a decrease in short-range molecular order and relative crystallinity (24.42 ± 0.06 %), and a loose semi-crystalline lamellar, which were beneficial to the followed double-enzymatic hydrolysis. Therefore, the HSS-ES displayed a superior porous structure and larger specific surface area (2.962 ± 0.002 m2/g) compared with double-enzymatic hydrolyzed porous starch (ES), resulting in the increase of water and oil absorption from 130.79 ± 0.50 % and 109.63 ± 0.71 % to 154.79 ± 1.14 % and 138.40 ± 1.18 %, respectively. In vitro digestion analysis showed that the HSS-ES had good digestive resistance derived from the higher content of slowly digestible and resistant starch. The present study suggested that high-speed shear as an enzymatic hydrolysis pretreatment significantly enhanced the pore formation of rice starch.

Advanced oxidation processes in the treatment of corn stalks

The depletion of fossil fuel reserves and severe environmental damage, resulting in climate change and global warming lead to a necessary shift to alternative renewable resources. Lignocellulose is a valuable feedstock for biorefineries, but its conversion is hindered by the limitations of conventional pretreatments lacking selectivity. This step should also be cost-effective and sustainable. In this paper, combined advanced oxidation techniques were applied for the treatment of corn stalks as a pretreatment for enzymatic hydrolysis. Their effect on delignification and cellulose digestibility was monitored. The combined non-thermal plasma/Fenton treatment appears to be suitable for breaking the complex lignocellulose structure, with a lignin content decrease of 39%. This treatment enhanced carbohydrate hydrolysis, resulting in 2.25 times increase in hexose yield, compared to the untreated sample. Long-term plasma treatment positively affected the textural properties, total porosity, and pore size diameter, of lignocellulose biomass. It enables the creation of materials with a stable system of pores and channels, for the unhindered diffusion of large organic molecules such as enzymes. Additionally, a combination of plasma treatment with Fenton reaction increased selectivity towards lignin degradation in comparison to independently applied Fenton treatment. This could be a significant advantage for a bottleneck in the current valorization of biomass.

SIMULTANEOUS HYDROLYSIS AND FERMENTATION OF RICE STRAW: EFFECT OF LIGNIN PRETREATMENT ON GLUCOSE AND ETHANOL CONCENTRATIONS

Lignin is a component of lignocellulosic materials which is relatively difficult to degrade. Its presence limits the use of lignocellulosic materials when they are converted to glucose and ethanol. This objective of the studi to reduce concentration of lignin contained in rice straw, carried out enzymatic hydrolysis and fermentation Pretreatment was carried out at a temperature of 100-140ºC and a NaOH concentration of 4- 10% for 16 hours. Hydrolysis and fermentation separately with the addition of cellulase enzymes and Saccharomyces cereviceae during fermentation. The nutrients used for bacterial growth included (NH4)2HPO4 0.5 g/L, MgSO4.7H2O 0.025 g/L. The media then incubated for 15 hours in a shaker at 30°C. at 80 rpm. The results of the study achieved a decrease in lignin during 16 hours the percentage reduction in lignin concentration for variations in NaOH concentrations of 4, 6, 8 and 10% were 33.76, 44.96, 55.73 and 31.41%. The best conditions were achieved during the delignification time of 16 hours at a concentration of 8% NaOH, which was a 44.96% reduction in deligtnification. Hydrolysis and fermentation of rice straw that for 6 to 48 hours, resulted the percentage of increasing glucose and ethanol concentrations before and after pretreatment was 32.99% and 39.99%.

The effects of various enzymatic saccharifications and microwave pretreatment durations on sugar yield and its property alterations of Chinese spirits distillers residues

This study evaluated the effect of different enzymatic hydrolysis and different microwave pretreatment durations on the sugar yield of Chinese spirits distillers residues (CSDR). Addition of both α-amylase and cellulase in the enzymatic hydrolysis of distillers grains resulted in a higher yield of reducing sugar (145.74 ± 4.20 mg·g–1). Fourier transform infrared spectroscopy (FTIR) revealed that different enzyme treatments degraded different functional groups of the cellulose structure. Subsequently, the highest reducing sugar yield (181.33 ± 6.42 mg·g–1) was achieved at microwave pretreatment time of 6 min and was 1.29-fold higher than that of the untreated sample. The differences in the structural features of CSDRs under various microwave pretreatment durations were characterized by scanning electron microscopy, FTIR spectroscopy, and X-ray diffraction. The data revealed that the optimal microwave pretreatment time at 6 min could obviously remove lignin, and then obtain the highest CrI value, achieving the highest reducing sugar yield.

Optimisation of pre-harvest sago frond sap for the production of l-lactic acid using Lactococcus lactis IO-1

The major restriction of sago palm plantation is the long maturation period for the starch extraction. As such, alternative commodity has to be identified to increase commercial value of sago palm especially from the by-product. Sago frond has been harvested to have numerous advantages as an alternative substrate for the production of biomaterial and biofuel such as lactic acid and bioethanol. This study focuses on effective approach to maximise the concentration of sugar in the substrate and to identify the ideal concentration of sago frond sap (SFSp) as sole media to produce l-lactic acid and grow L. lactis IO-1. Result shows that SFSp extracted from sago rachis using a roller press machine contained glucose (43.8 g/L), xylose (17.3 g/L) as free sugars and starch (5.55 g/L). Combination of enzymatic hydrolysis and sterilisation pre-treatment was found to maximise the concentration of total carbon source (68 g/L) and sterilised sago frond sap suitable to be used for fermentation process. The ideal concentration of SFSp that was determined at 50% dilution produces the highest amount of l-lactic acid (24.02 g/L) synergist by most efficient sugar consumption (89.93%). The use of SFSp as fermentation medium for l-lactic acid production generated maximum biomass concentration of 14.53 g/L. The utilisation of SFSp extracted from pre-harvest sago frond as substrate promote efficiency of l-lactic acid production associated to exceptional growth performance of L. lactis IO-1. In conclusion, the concept of utilizing by-product from sago palm as novel raw material promise reliable resources and superiority of L. lactis IO-1 to metabolise sugar in SFSp promote lucrative and ethical production of l-lactic acid.

Hybridising plasma functionalized water and ultrasound pretreatment for enzymatic protein hydrolysis of Larimichthys polyactis: Parametric screening and optimization

Hybridising plasma functionalized water and ultrasound pretreatment for the enzymatic hydrolysis (HPUEH) of Larimichthys polyactis was evaluated by adopting Plackett-Burman design for parametric screening of six key variables, and Box-Behnken design for optimizing three most significant variables including plasma generating voltage (PV), ultrasound treatment time (UT), and enzyme concentration (EC). The models developed for predicting the degree of hydrolysis (DoH), protein recovery (PVY), and soluble protein content (SPC) were sufficiently fitted to the experimental data (R2 ≥ 0.966) with non-significant lack of fit and used for determining the optimum conditions as PV of 70 V, UT of 15 min, and EC of 1.787%, with predictive values of 27.74%, 85.62%, and 3.28 mg/mL for DoH, PVY, and SPC, respectively. HPUEH presented hydrolysates with smaller peptide sizes and molecular weights, enhanced DoH, PVY, SPC, amino acids and antioxidant activity, but reduced emulsifying and foaming properties when compared with conventional enzymatic hydrolysis.

Effects of enzymatic hydrolysis and alkalization pretreatment on biohydrogen production by chlorella photosynthesis

The effects of alkalization pretreatment and enzymolysis on biohydrogen production with Chlorella vulgaris microalgae biomass by photosynthesis were studied, the alkalization pretreatment enzymolysis was to alkalize biomass raw materials before enzymolysis, the biohydrogen production kinetics equation of microalgae biomass was put forward by comparing the biohydrogen process of enzymatic hydrolysis with that of alkaline pretreatment enzymatic hydrolysis. The experimental results show: the optimum initial substrate concentration for biohydrogen production by enzymatic hydrolysis and alkaline pretreatment was 24 g/L, the maximum biohydrogen was 132.1 mL and 294.5 mL, the maximum specific biohydrogen production was 22.0 mL/g and 49.1 mL/g, and the maximum biohydrogen content was 43.9% and 56.8%. The effect of biohydrogen production by enzymatic hydrolysis after alkaline pretreatment of microalgae biomass is obviously better than that by direct enzymatic hydrolysis, which provides scientific reference and development of high efficiency and low cost biohydrogen production technology by photosynthesis of microalgae biomass.

Lewis base enhanced neutral deep eutectic solvent pretreatment for enzymatic hydrolysis of corn straw and lignin characterization

In order to improve the pretreatment behavior of neutral deep eutectic solvent (DES), a novel method was proposed by using three types of Lewis base (sodium carbonate, sodium sulfite and sodium acetate as catalysts to pretreat corn straw at 120 °C for 3 h. As compared to DES, DES with Na2SO3, DES with NaAC and DES with Na2CO3, all can remove most of hemicellulose and lignin in pretreated corn straw. Meanwhile, the 94.5% of glucose yield was obtained treated by DES with Na2CO3 and was approximately five-fold higher than that of the untreated substrate at an enzyme loading of 15 FPU/g material. The regenerated lignin displayed well-preserved structures, and possessed a high purity (more than 84%), narrow molecular weight distribution (PDI <2.4), excellent thermal stability. Overall, this work provided detailed analysis for efficient deconstruction of corn straw for future industrialized application.

One-Pot Pretreatment for Furfural Production and Enhancing Enzymatic Hydrolysis by Des-Based Biphasic System: Chemical, Topochemical, and Morphological Changes

One-Pot Pretreatment for Furfural Production and Enhancing Enzymatic Hydrolysis by Des-Based Biphasic System: Chemical, Topochemical, and Morphological Changes

Optimization of Microwave Assisted Organosolv Pretreatment for Enzymatic Hydrolysis of Cherry Tree Pruning and Pistachio Shells

Optimization of Microwave Assisted Organosolv Pretreatment for Enzymatic Hydrolysis of Cherry Tree Pruning and Pistachio Shells

Synergistic Effect of Enzyme Hydrolysis and Microwave Reactor Pretreatment as an Efficient Procedure for Gluten Content Reduction

In this study, we assessed the effects of microwave irradiation of wheat gluten proteins as a pretreatment performed in a microwave reactor that could accurately control process parameters as a function of power and temperature, as well as comparing it with conventional heat treatment. The aim was to identify suitable combinations of partial enzymatic hydrolysis and microwave pretreatment parameters to produce gluten hydrolysates with reduced allergenicity and conserved techno-functional features for food application. FTIR analysis, and total and reactive SH group contents confirmed that the microwave-controlled heating can significantly change the secondary structure and conformation of gluten protein. The microwave treatment had the largest effect at 200 W and 100 °C, at which the content of gluten has been reduced by about 2.5-fold. The microwave pretreatment also accelerated the enzymatic hydrolysis of gluten, changing the kinetic profile. The apparent hydrolysis rate constants (k2) were 1.00, 3.68, 3.48, 4.64 and 4.17 min−1 for untreated gluten, and those pretreated with microwave power of 200, 400, 600 and 800 W, respectively. Compared to the heat treatment, it appeared that microwave specific non-thermal effects had a significant influence on the gluten structure and allergenicity and, in combination with the enzymatic hydrolysis, ultimately yielded protein hydrolysates with enhanced antioxidant and functional properties.

Optimization of Enzymatic Hydrolysis Conditions for the Production of Crisp Plum Juice by Response Surface Methodology

Objective: To investigate the optimum enzymolysis extraction process conditions of plum fruit, and to provide theoretical bases fordeep processing andutilizationof itsresources. Method: The juice yield was used as an indicator. On the basis of single-factor experiments, response surface methodology (RSM) was employed to optimize the enzymatic hydrolysis pretreatment conditions for extracting fruit juice from crisp plum with methods of adding enzymes, including pectinases, cellulase and complex enzyme consisted of pectinases and cellulase. Result: The results suggested that the extraction parameters in the order of significance were enzymolysis temperature, enzyme concentration, enzymolysis pH, and enzymolysis time by response surface analysis. The optimum conditions of enzymolysis with pectinases were pectinases concentration 0.45 g/L, enzymolysis temperature 38 ℃, enzymolysis pH3.8 and enzymolysis time 72 min, in which the average juice yield of crisp plum was 78.63%. The optimum conditions of enzymolysis with cellulase were cellulase concentration 0.55 g/L, enzymolysis temperature 41 ℃, enzymolysis pH4.2 and enzymolysis time 105 min, in which the average juice yield of crisp plum was 74.33%. The optimum conditions of enzymolysis with complex enzyme were pectinases concentration 0.45 g/L, cellulase concentration 0.55 g/L, enzymolysis temperature 41 ℃, enzymolysis pH4.0 and enzymolysis time 87 min, in which the average juice yield of crisp plum was 81.51%. Conclusion: In the extract process of crisp plum juice, juice yields all increased when extracting juice, by adding pectinases, cellulase or complex enzyme consisted of pectinases and cellulose on the corresponding optimal conditions of enzymatic hydrolysis. The study provides technical references for the product development of Guizhou plum fruit.