Enzymatic Hydrolysis Conditions Research Articles

Biodegradability of renewable isosorbide and sebacate-based copolyesters

The growing environmental concerns associated with the use of plastics highlight the need to mitigate carbon emissions and environmental pollution via biodegradable plastics development. Herein, biotechnologically accessible and renewable building blocks, namely 1,4-butanediol and sebacic acid, were copolymerized with carbohydrate-derived isosorbide to afford random poly(butylene-co-isosorbide sebacate) with variable isosorbide content. The thermal stabilities of these copolyesters and their biodegradabilities under (non)enzymatic hydrolysis, compost, soil, and marine conditions were examined as functions of isosorbide content. With the increasing isosorbide content, the glass transition temperature increased, whereas the crystallinity and melting temperature decreased. Isosorbide incorporation enhanced hydrolyzability under alkaline and enzymatic conditions, while demonstrating minimal impact under neutral and acidic conditions. The in-compost degradation rate increased with the increasing isosorbide content because of the concomitant decrease in melting temperature and crystallinity. In soil and marine environments, the copolyesters were degraded faster than poly(butylene sebacate). At 30 mol% isosorbide, the degradation extent reached 97.2 and 68.3% after eight-week degradation in soil and 32-week degradation in a marine environment, respectively. This study is the first to report the biodegradability and degradation mechanisms of poly(butylene-co-isosorbide sebacate) and provides valuable insights into customizing the synthesis of biodegradable plastics to meet the degradation cycle requirements under various environmental conditions.

Optimization of enzymatic hydrolysis of cellulose extracted from bamboo culm for bioethanol production by Saccharomyces cerevisiae modified via CRISPR/Cas9

In the context of biorefinery, researchers have been looking for lignocellulosic biomasses and ideal treatments to produce economically viable biofuels. In this scenario, the bamboo culm appears as a plant matrix of great potential, given the high cellulose content of low crystallinity. Thus, the objective and differential of this work was to determine the best conditions for enzymatic hydrolysis of cellulose extracted from bamboo culm and to evaluate its potential application in the production of bioethanol through Separate Hydrolysis and Fermentation (SHF) and Saccharification and Simultaneous Fermentation (SSF) by Saccharomyces cerevisiae modified via CRISPR/Cas9. The average cellulose extraction yield was 41.87 % with an extraction efficiency of 86.76 %. In general, as the hydrolysis time increased, an increase in glucose production was observed in almost all assays, with higher hydrolysis efficiency values at 72 h. The results ranged from 2.09 to 19.8 g/L of glucose obtained with efficiency values of 10.47 to 99 %. The best conditions were found in test 5 (temperature of 36 °C and pH 5.0, with only 10 FPU/g of substrate Cellic Ctec2 Novozymes ® cocktail). It is observed that for all hydrolysis times the independent variables pH and temperature were significant under the hydrolysis efficiency, showing a negative effect, indicating that higher values of the same promote lower values of the response variable. For bioethanol production, a maximum concentration of 7.84g/L was observed for the SSH process after 4 h of fermentation, while for the SSF process it was 12.6 g/L after 24 h of fermentation, indicating the large potential of the simultaneous process together with the application of bamboo culm biomass for high production of biofuel.

Optimizing the Conditions of Pretreatment and Enzymatic Hydrolysis of Sugarcane Bagasse for Bioethanol Production.

The agricultural waste sugarcane bagasse (SCB) is a kind of plentiful biomass resource. In this study, different pretreatment methods (NaOH, H2SO4, and sodium percarbonate/glycerol) were utilized and compared. Among the three pretreatment methods, NaOH pretreatment was the most optimal method. Response surface methodology (RSM) was utilized to optimize NaOH pretreatment conditions. After optimization by RSM, the solid yield and lignin removal were 54.60 and 82.30% under the treatment of 1% NaOH, a time of 60 min, and a solid-to-liquid ratio of 1:15, respectively. Then, the enzymolysis conditions of cellulase for NaOH-treated SCB were optimized by RSM. Under the optimal enzymatic hydrolysis conditions (an enzyme dose of 18 FPU/g, a time of 64 h, and a solid-to-liquid ratio of 1:30), the actual yield of reducing sugar in the enzyme-treated hydrolysate was 443.52 mg/g SCB with a cellulose conversion rate of 85.33%. A bacterium, namely, Bacillus sp. EtOH, which produced ethanol and Baijiu aroma substances, was isolated from the high-temperature Daqu of Danquan Baijiu in our previous study. At last, when the strain EtOH was cultured for 36 h in a fermentation medium (reducing sugar from cellulase-treated SCB hydrolysate, yeast extract, and peptone), ethanol concentration reached 2.769 g/L (0.353%, v/v). The sugar-to-ethanol and SCB-to-ethanol yields were 13.85 and 11.81% in this study, respectively. In brief, after NaOH pretreatment, 1 g of original SCB produced 0.5460 g of NaOH-treated SCB. Then, after the enzymatic hydrolysis, reducing sugar yield (443.52 mg/g SCB) was obtained. Our study provided a suitable method for bioethanol production from SCB, which achieved efficient resource utilization of agricultural waste SCB.

Determination of Flavonoids and Phenolic Acids in the Liver of Wistar Rats after a Dietary Enrichment with Corinthian Currant (Vitis vinifera L., var. Apyrena): A Liquid Chromatography-Tandem Mass Spectrometry Study.

Corinthian currants are dried fruits produced from Vitis vinifera L. var. Apyrena grape. This study investigated the distribution of phenolic compounds in male Wistar rat livers following two distinct Corinthian currant long-term dietary intake protocols (3 and 10% w/w). Method optimization, comparing fresh and lyophilized tissues, achieved satisfactory recoveries (>70%) for most analytes. Enzymatic hydrolysis conditions (37 °C, pH 5.0) minimally affected phenolics, but enzyme addition showed diverse effects. Hydrolyzed lyophilized liver tissue from rats consuming Corinthian currants (3 and 10% w/w) exhibited elevated levels of isorhamnetin (20.62 ± 2.27 ng/g tissue and 33.80 ± 1.38 ng/g tissue, respectively), along with similar effects for kaempferol, quercetin, and chrysin after prolonged Corinthian currant intake. This suggests their presence as phase II metabolites in the fasting-state liver. This study is the first to explore phenolic accumulation in rat liver, simulating real conditions of dried fruit consumption, as seen herein with Corinthian currant.

Enzymatic Hydrolysis of Protein Hydrolysate from Pangasius sp. by-Product using Bromelain

Fish protein hydrolysate (FPH) is a product resulting from the degradation of fish protein into simple peptides and amino acids through hydrolysis. This study aims to optimise the enzymatic hydrolysis conditions of Pangasius sp. by-products to produce high-quality fish protein hydrolysate. Bromelain enzyme was used as the catalyst for hydrolysis. The degree of hydrolysis (DH), pH and antioxidant activity of FPH were used as response parameters. The optimisation was done using response surface methodology (RSM) by applying two factors (enzyme concentration and incubation time) with a 3-level Central Composite Design (CCD) model. The result showed that the bromelain concentration and incubation time of catfish protein hydrolysate gave significantly different effects (p<0.05) on the response parameters of Pangasius protein hydrolysate. Hydrolysis of Pangasius protein with 0.04% bromelain enzyme and incubation time of 2.8 hours resulted in DH, pH and DPPH antioxidant activity of 35.88%, 7.07 and 29.86%, respectively. The response value of Pangasius protein hydrolysate was within the range of the predicted value of hydrolysate. Therefore, the optimum conditions suggested by RSM can be used in the future production of Pangasius FPH. In addition, amino acid profiles of Pangasius protein hydrolysate showed high concentrations of Glycine, L-glutamic acid and L-aspartic Acid.

Study of Processing Conditions during Enzymatic Hydrolysis of Deer By-Product Tallow for Targeted Changes at the Molecular Level and Properties of Modified Fats.

In most cases, the unused by-products of venison, including deer tallow, are disposed of in rendering plants. Deer tallow contains essential fatty acids and can be used to prepare products for everyday food and advanced applications. This work aimed to process deer tallow into hydrolyzed products using microbial lipases. A Taguchi design with three process factors at three levels was used to optimize the processing: amount of water (8, 16, 24%), amount of enzyme (2, 4, 6%), and reaction time (2, 4, 6 h). The conversion of the tallow to hydrolyzed products was expressed by the degree of hydrolysis. The oxidative stability of the prepared products was determined by the peroxide value and the free fatty acids by the acid value; further, color change, textural properties (hardness, spreadability, stickiness, and adhesiveness), and changes at the molecular level were observed by Fourier transform infrared spectroscopy (FTIR). The degree of hydrolysis was 11.8-49.6%; the peroxide value ranged from 12.3 to 29.5 µval/g, and the color change of the samples expressed by the change in the total color difference (∆E*) was 1.9-13.5. The conditions of enzymatic hydrolysis strongly influenced the textural properties: hardness 25-50 N, spreadability 20-40 N/s, and stickiness < 0.06 N. FTIR showed that there are changes at the molecular level manifested by a decrease in ester bonds. Enzymatically hydrolyzed deer tallow is suitable for preparing cosmetics and pharmaceutical matrices.

Enzymatic hydrolysis of soybean hulls to produce a potential carbon source for cultivation of exopolysaccharide-producing diazotrophic bacteria

Lignocellulosic biomass, such as soybean hulls, constitutes a promising alternative substrate for application in biotechnological processes, as it is abundant, inexpensive, and renewable. However, its use is limited by the inability of bacteria and yeasts to assimilate it. To solve this problem, pretreatment and enzymatic hydrolysis conditions of soybean hulls were studied to produce a substrate capable of assimilating by exopolysaccharide-producing diazotrophic bacteria. Pretreatments by microwave (power of 1.4 kW during 30 s, 60 s, or 120 s) or autoclave (1.1 atm and 121 °C during 15 min, 30 min, or 60 min) were tested to favor the enzymatic action. Celluclast 1.5L® was used as a biocatalyst. The best results for pretreatment were obtained in an autoclave (121 °C for 15 min), with an increase of 6.7 times in the concentration of reducing sugars (40.4 g/L) in relation to hydrolysis without any previous pretreatment (6.0 g/L). The best hydrolysis conditions were established as a temperature of 50 °C, pH 5.3, and enzyme/substrate ratio of 20 FPU/g, reaching 40.4 g/L of reducing sugars. The hydrolysate was composed mainly of cellobiose, followed of glucose, xylose, and arabinose. It was used for the cultivation of Mesorhizobium sp. Semia 816, producing 1.26 g/L biomass and 3.93 g/L exopolysaccharides (EPS). An increase in viscosity with a pH decrease was observed, as well as a high degradation temperature. These results proved that soybean hull hydrolysate can be assimilated by Mesorhizobium sp. Semia 816 to produce EPS with potential industrial applications.

Simultaneous Saccharification and Fermentation for Isobutanol Production from Banana Peel

Each year, near 40 million tons of banana peels are discarded around the world. This plant biomass could potentially be utilized for energy production. Simultaneous saccharification and fermentation (SSF) is an effective method for producing biofuels from plant biomasses. Since SSF with enzymatic hydrolysis and fermentation are performed simultaneously in the same reactor, the production process is simpler than most existing methods. Here, we describe isobutanol production using SSF with hydrothermally treated banana peel samples and an Escherichia coli strain able to utilize glucose and xylose to produce isobutanol. To enhance the glucose and xylose concentrations, the reaction conditions for the enzymatic hydrolysis of plant biomass using two kinds of saccharification enzymes were optimized, including the enzyme unit ratio, reaction temperature and sample gram. When the optimized conditions for enzymatic hydrolysis were applied to SSF, the glucose and xylose produced from the hydrothermally treated samples were consumed, producing isobutanol. Moreover, the isobutanol concentration increased with an increasing initial culture pH, reaching 1.27 g/L at pH 6.5, which was consistent with the optimal initial culture pH for isobutanol production by this E. coli strain. Taken together, these results indicate that the established method is potentially useful for industrial isobutanol production.

Pretreatment and enzymatic hydrolysis optimization of lignocellulosic biomass for ethanol, xylitol, and phenylacetylcarbinol co-production using Candida magnoliae.

Cellulosic bioethanol production generally has a higher operating cost due to relatively expensive pretreatment strategies and low efficiency of enzymatic hydrolysis. The production of other high-value chemicals such as xylitol and phenylacetylcarbinol (PAC) is, thus, necessary to offset the cost and promote economic viability. The optimal conditions of diluted sulfuric acid pretreatment under boiling water at 95°C and subsequent enzymatic hydrolysis steps for sugarcane bagasse (SCB), rice straw (RS), and corn cob (CC) were optimized using the response surface methodology via a central composite design to simplify the process on the large-scale production. The optimal pretreatment conditions (diluted sulfuric acid concentration (% w/v), treatment time (min)) for SCB (3.36, 113), RS (3.77, 109), and CC (3.89, 112) and the optimal enzymatic hydrolysis conditions (pretreated solid concentration (% w/v), hydrolysis time (h)) for SCB (12.1, 93), RS (10.9, 61), and CC (12.0, 90) were achieved. CC xylose-rich and CC glucose-rich hydrolysates obtained from the respective optimal condition of pretreatment and enzymatic hydrolysis steps were used for xylitol and ethanol production. The statistically significant highest (p ≤ 0.05) xylitol and ethanol yields were 65% ± 1% and 86% ± 2% using Candida magnoliae TISTR 5664. C. magnoliae could statistically significantly degrade (p ≤ 0.05) the inhibitors previously formed during the pretreatment step, including up to 97% w/w hydroxymethylfurfural, 76% w/w furfural, and completely degraded acetic acid during the xylitol production. This study was the first report using the mixed whole cells harvested from xylitol and ethanol production as a biocatalyst in PAC biotransformation under a two-phase emulsion system (vegetable oil/1M phosphate (Pi) buffer). PAC concentration could be improved by 2-fold compared to a single-phase emulsion system using only 1M Pi buffer.

Effects of soybean endogenous enzyme hydrolysis on the quality of soymilk after blanching

This study examined the relationship between the endogenous enzymatic hydrolysis conditions and the quality and flavor of soymilk derived from blanched soybeans. Results represented that following blanching, the lipoxygenase activity of soybeans decreased by 88.50% and the endogenous protease activity greatly improved compared to unblanched. During the subsequent endogenous enzymatic hydrolysis, the stability factor and sensory score dropped as the amount of okara rose, although the content of peptides and amino acids nitrogen increased. At an enzymolysis temperature of 50 °C, the soymilk had the highest sensory score. After 60 min of enzymolysis, the beany odor was weakened maximumly; the levels of polypeptide and amino acid nitrogen increased by 45.00% and 43.33%, respectively. Enzymatic hydrolysis at 50 °C for 60 min without okara generated the finest soymilk. Blanching diminished the primary components of the beany odor of raw soymilk. Enzymolysis of blanched pretreatment soymilk further dropped the content of beany odor components and exhibited a richer variety and concentration of volatile components. Following the hydrolysis of endogenous enzymes generated after blanching, the overall quality of soymilk was enhanced.

The Production of Bioactive Peptides by Optimization of Enzymatic Hydrolysis Process of Protein from Tilapia Fish Skin Waste (Oreochromis niloticus, Linnaeus 1758) using Alcalase 2.4.L

Aims: This study aimed at developing bioactive peptides by optimization of the enzymatic hydrolysis process of protein from tilapia fish skin waste (Oreochromis niloticus, Linnaeus 1758) using alcalase 2.4.L. Background: Natural bioactive peptides are considered to have low toxicity and therapeutic properties as antioxidants. Objective: The conditions of protein hydrolysis obtained from tilapia fish skin waste (Oreochromis niloticus, Linnaeus 1758) were optimized using alcalase 2.4.l Methods: In this study, the hydrolysis of protein obtained from tilapia fish skin waste (TFSW) was optimized using alcalase 2.4.L by central composite design (CCD). Degree of hydrolysis (DH), radical scavenging activities (DPPH), and ferric-reducing antioxidant power (FRAP) were used as dependent variables, whereas temperature, pH, and proportion of enzyme to the substrate (PE%) as independent variables. Results: The optimum degree of hydrolysis DH%, DPPH, and FRAP were achieved at a temperature of 58.4 ℃, a pH of 8.7, except for DPPH, which was achieved at a pH of 7.0. Conclusion: The present work demonstrated that TFSW could be used as a source to produce bioactive peptides with significant antioxidant activities under specific conditions of enzymatic hydrolysis.

Tolerance of engineered Rhodosporidium toruloides to sorghum hydrolysates during batch and fed-batch lipid production

BackgroundOleaginous yeasts are a promising candidate for the sustainable conversion of lignocellulosic feedstocks into fuels and chemicals, but their growth on these substrates can be inhibited as a result of upstream pretreatment and enzymatic hydrolysis conditions. Previous studies indicate a high citrate buffer concentration during hydrolysis inhibits downstream cell growth and ethanol fermentation in Saccharomyces cerevisiae. In this study, an engineered Rhodosporidium toruloides strain with enhanced lipid accumulation was grown on sorghum hydrolysate with high and low citrate buffer concentrations.ResultsBoth hydrolysis conditions resulted in similar sugar recovery rates and concentrations. No significant differences in cell growth, sugar utilization rates, or lipid production rates were observed between the two citrate buffer conditions during batch fermentation of R. toruloides. Under fed-batch growth on low-citrate hydrolysate a lipid titer of 16.7 g/L was obtained.ConclusionsCitrate buffer was not found to inhibit growth or lipid production in this engineered R. toruloides strain, nor did reducing the citrate buffer concentration negatively affect sugar yields in the hydrolysate. As this process is scaled-up, $131 per ton of hydrothermally pretreated biomass can be saved by use of the lower citrate buffer concentration during enzymatic hydrolysis.Graphical

Preparation, Characterization, and Antioxidant Properties of Selenium-Enriched Tea Peptides.

The research on the activity of selenium (Se)-enriched agricultural products is receiving increasing attention since Se was recognized for its antioxidant activities and for its enhancement of immunity in trace elements. In this study, antioxidant Se-containing peptides, namely, Se-TAPepI-1 and Se-TAPepI-2, were optimally separated and prepared from Se-enriched tea protein hydrolysates by ultrafiltration and Sephadex G-25 purification, and subsequently, their physicochemical properties, oligopeptide sequence, and potential antioxidant mechanism were analyzed. Through the optimization of enzymatic hydrolysis conditions, the Se-enriched tea protein hydrolyzed by papain exhibited a better free radical scavenging activity. After separation and purification of hydrolysates, the two peptide fractions obtained showed significant differences in selenium content, amino acid composition, apparent morphology, peptide sequence, and free radical scavenging activity. Therein, two peptides from Se-TAPepI-1 included LPMFG (563.27 Da) and YPQSFIR (909.47 Da), and three peptides from Se-TAPepI-2 included GVNVPYK (775.42 Da), KGGPGG (552.24 Da), and GDEPPIVK (853.45 Da). Se-TAPepI-1 and Se-TAPepI-2 could ameliorate the cell peroxidation damage and inflammation by regulating NRF2/ARE pathway expression. Comparably, Se-TAPepI-1 showed a better regulatory effect than Se-TAPepI-2 due to their higher Se content, typical amino acid composition and sequence, higher surface roughness, and a looser arrangement in their apparent morphology. These results expanded the functional activities of tea peptide and provided the theoretical basis for the development of Se-containing peptides from Se-enriched tea as a potential natural source of antioxidant dietary supplements.

Extraction, optimization, and functional quality evaluation of carotenoproteins from shrimp processing side streams through enzymatic process.

The study aimed to develop an effective and eco-friendly enzymatic process to extract carotenoproteins from shrimp waste. The optimization of enzymatic hydrolysis conditions to maximize the degree of deproteinization (DDP) of carotenoprotein from shrimp head waste (SHW) and shrimp shell waste (SSW) was conducted separately using the Box-Behnken design of response surface methodology (RSM). To achieve a maximum DDP of 92.32% for SSW and 96.72% for SHW, the optimal hydrolysis conditions were determined as follows: temperature (SSW: 53.13°C; SHW: 45.90°C), pH (SSW: 7.13; SHW: 6.78), time (SSW: 90min; SHW: 61.18min), and enzyme/substrate ratio (SSW: 2g/100g; SHW: 1.18g/100g). The carotenoprotein effluent obtained was subjected to spray drying and subsequently assessed for color, nutritional, and functional characteristics. The carotenoprotein from shrimp shell (CpSS) contained a higher essential amino acid score than carotenoprotein from shrimp head (CpSH). CpSS had a higher whiteness index of 82.05, while CpSH had 64.04. Both CpSS and CpSH showed good functional properties viz solubility, emulsion, and foaming properties. The maximum solubility of CpSH and CpSS was determined to be 92.94% and 96.48% at pH 10.0, respectively. The highest emulsion capacity (CpSH: 81.33%, CpSS: 70.13%) and stability (CpSH: 57.06%, CpSS: 63.05%) were observed at 3% carotenoprotein concentration. Similarly, the highest values of foaming capacity (CpSH: 27.66%, CpSS: 105.5%) and stability (CpSH: 23.83%, CpSS: 105.33%) were also found at the same 3% carotenoprotein concentration. In conclusion, the carotenoproteins obtained from shrimp waste showed favorable attributes in terms of color, amino acid composition, and functional properties. These findings strongly suggest the potential applicability of CpSS and CpSH as valuable resources in various domains. CpSS, with its higher whiteness index, greater amino acid content, and superior functional characteristics, may find suitability as functional ingredients in human food products. Conversely, CpSH could be considered for incorporation into animal feed formulations.

Changes in various lignocellulose biomasses structure after microwave-assisted hydrotropic pretreatment

Effective pretreatment of lignocellulosic biomass combined with delignification is a condition for effective enzymatic hydrolysis of cellulose, which is of key significance for the efficiency of the process of production of cellulosic ethanol. Becoming aware of the full range of changes in the structure of lignocellulose as a result of biomass pretreatment is important in view of the necessity to optimise the process of technological production of bioethanol. Our research was aimed at a comprehensive analysis of changes in structure of pine chip (softwood), beech chip (hardwood) and wheat straw (non-wood) biomasses resulting from a newly developed pretreatment method combining the use of hydrotrope in the form of sodium cumene sulfonate and microwave radiation. The performed analyses of the biomass composition indicate a high effectiveness of the proposed pretreatment method in the area of biomass delignification and hemicellulose removal. An effective removal of amorphous substances, i.e. lignin and hemicellulose, led to an increase in the crystallinity of pine chip biomass to 55%, and beech chips and wheat straw biomasses to 61%.

Preparation of starch nanoparticles by jet cavitation and enzymatic hydrolysis and their application in starch films

Potato starch was subjected to jet cavitation, freeze-thaw, ultrasound, acid, and enzymatic treatments to prepare starch nanoparticles. Enzymatic hydrolysis after jet cavitation pretreatment was found to be efficient. Therefore, enzymatic hydrolysis conditions of jet cavitation-treated starch were optimized. The smallest starch nanoparticles were obtained when the enzyme concentration was 66.68 nkat, starch concentration was 10 g/dL, and enzymatic hydrolysis duration was 3 h. The prepared starch nanoparticles showed a mixture of B and V-type crystalline structures with reduced relative crystallinity. A combination of potato starch nanoparticles and tea polyphenols was incorporated into potato starch-based edible films. The elongation at break of edible films significantly improved with the incorporation of starch nanoparticles. Additionally, the water resistance, tensile strength, and antioxidant activity of films improved with the addition of starch nanoparticles and tea polyphenols. Furthermore, the FTIR analysis indicated comparable spectra for all the starch-based films, except for the tea polyphenols-incorporated film, which exhibited a distinct band at 1605 cm−1.

Optimization of Enzymatic Hydrolysis of Mackerel (Rastrelliger sp.) Muscle Protein Hydrolysate Using Response Surface Methodology

Mackerel (Rastrelliger sp.) is a widely distributed epipelagic species in South East Asia. Mackerel has a high amount nutrient such as protein (20.83 %) and fat (1.03 %). The high amount of protein and low amount of fat will allow it to be used as a material to produce a good protein hydrolysate. The aim of this study is to determine the optimal enzymatic hydrolysis conditions (time, temperature, and pH) using Response Surface Methodology (RSM). Mackerel Protein Hydrolysate (MPH) was prepared using commercial Flavourzyme. Optimization of MPH was performed by employing Box Behnken Design method of RSM. SN-TCA method was used to calculate the degree of hydrolysis (DH) which is the key parameter in hydrolysis reaction. Optimum hydrolysis conditions were obtained at pH 7, temperature 55°C and 60 min of process. Under these conditions the DH obtained was 17.7293 % with 4% enzyme to substrate ratio. The suggested model for the hydrolysis process is quadratic with the desirability factor of 1. The MPH was further assessed for its amino acid composition using High Performance Liquid Chromatography (HPLC). The hydrolysis process increases the amino acid amounts namely L-Glutamic Acid (19.77%), L-Valin (14.20%), L-Aspartic Acid (11.42%), Glycine (11.04%), L-Alanin (14.20%), L-Prolin (16.80%), and L-Histidin (27.06%). The study suggested that mackerel muscle can be considered to be utilized as fish protein hydrolysis materials.

Investigation into Optimal Conditions for Enzymatic Hydrolysis of Cassava Starch to Glucose by Amylase from Rice

The challenge of finding locally available materials in abundance to meet up with the increase in demand for glucose syrup necessitated this study. Enzymatic hydrolysis of cassava starch to glucose using glucose amylase sourced from rice was conducted. A-3 factor with 6 levels factorial viz. substrate concentration (0.5, 1.0, 1.5, 2.0, 2.5 and 3.0% w/v), pH (4, 5, 6, 7, 8 and 9) and temperature (30, 40, 50, 60, 70 and 80 °C) experiment were employed. Rice malt was prepared and enzyme activated. Starch (substrate), buffer solutions, standard glucose solution and its calibration curve were also prepared. Starch was hydrolyzed by α-amylase and tested for presence of reducing sugar using Benedict solution. Time course of the reaction was studied and enzyme activity determined. It was observed that as reaction time increased (t), amount of glucose produced [P] initially increased but soon recorded infinitesimal increase and later assumed constant. The effects of substrate concentration, pH and temperature were found to be essential on glucose production. Statistical analysis on the effect of substrate concentration [S], reaction time and their interactions showed significant impact at probability level of (p) = 0.05.

Potential of Human Hemoglobin as a Source of Bioactive Peptides: Comparative Study of Enzymatic Hydrolysis with Bovine Hemoglobin and the Production of Active Peptide α137-141.

Cruor, the main component responsible for the red color of mammalian blood, contains 90% haemoglobin, a protein considered to be a rich source of bioactive peptides. The aim of the present study is to assess the potential of human hemoglobin as a source of bioactive peptides, compared with bovine hemoglobin, which has been extensively studied in recent years. More specifically, the study focused on the α137-141 fragment of bovine haemoglobin (TSKYR), a small (653 Da) hydrophilic antimicrobial peptide. In this work, the potential of human hemoglobin to contain bioactive peptides was first investigated in silico in comparison with bovine hemoglobin-derived peptides using bioinformatics tools. The blast results showed a high identity, 88% and 85% respectively, indicating a high similarity between the α and β chains. Peptide Cutter software was used to predict cleavage sites during peptide hydrolysis, revealing major conservation in the number and location of cleavage sites between the two species, while highlighting some differences. Some peptides were conserved, notably our target peptide (TSKYR), while others were specific to each species. Secondly, the two types of hemoglobin were subjected to similar enzymatic hydrolysis conditions (23 °C, pH 3.5), which showed that the hydrolysis of human hemoglobin followed the same reaction mechanism as the hydrolysis of bovine hemoglobin, the 'zipper' mechanism. Concerning the peptide of interest, α137-141, the RP-UPLC analyses showed that its identification was not affected by the increase in the initial substrate concentration. Its production was rapid, with more than 60% of the total α137-141 peptide production achieved in just 30 min of hydrolysis, reaching peak production at 3 h. Furthermore, increasing the substrate concentration from 1% to 10% (w/v) resulted in a proportional increase in α137-141 production, with a maximum concentration reaching 687.98 ± 75.77 mg·L-1, approximately ten-fold higher than that obtained with a 1% (w/v) concentration. Finally, the results of the UPLC-MS/MS analysis revealed the identification of 217 unique peptides in bovine hemoglobin hydrolysate and 189 unique peptides in human hemoglobin hydrolysate. Of these, 57 peptides were strictly common to both species. This revealed the presence of several bioactive peptides in both cattle and humans. Although some had been known previously, new bioactive peptides were discovered in human hemoglobin, such as four antibacterial peptides (α37-46 PTTKTYFPHF, α36-45 FPTTKTYFPH, α137-141 TSKYR, and α133-141 STVLTSKYR), three opioid peptides (α137-141 TSKYR,β31-40 LVVYPWTQRF,β32-40, VVYPWTQRF), an ACE inhibitor (β129-135 KVVAGVA), an anticancer agent (β33-39 VVYPWTQ), and an antioxidant (α137-141 TSKYR). To the best of our knowledge, these peptides have never been found in human hemoglobin before.

Combining heterogeneous photocatalysis and enzymatic catalysis via membrane: Conversion of biomass for H2 production from water

Solar reforming cellulosic biomass into hydrogen is an attractive research topic for sustainable biomass waste utilization and renewable energy development. To exert the advantages of enzymatic catalysis and heterogeneous photocatalysis, a glass fiber membrane integrated process that combines enzymatic hydrolysis of cellulose with sacrificial photocatalytic H2 production from water under mild condition has been proposed as an example of integrating enzymatic catalysis and heterogeneous photocatalysis. Specifically, a low−cost Cu0.5Ni0.5−TiO2 photocatalyst has been developed with presenting remarkable H2 production performance even comparable with Pt−TiO2 under UV light irradiation. The synergistic effect of Cu and Ni co−deposition onto TiO2 has been found to improve the photocatalytic H2 production. The condition for enzymatic hydrolysis of cellulose to generate glucose has been optimized in terms of reaction temperature, solution pH, types of cellulase and inorganic ions in order to obtain higher yields of glucose. To integrate the enzymatic catalysis and photocatalysis together, the glass fiber membrane with superior glucose penetration capability has been screened out. Lastly, the coupling of photocatalytic H2 production from water based on the Cu0.5Ni0.5 −TiO2 photocatalyst and enzymatic hydrolysis of cellulose has been quantitively evaluated in both mixed and membrane−separation systems. The membrane−separation system can avoid the depletion of cellulase activity induced by photocatalytic oxidation, and thus presents higher H2 production efficiencies with apparent quantum efficiency of 3.07 % at 365 ± 10 nm irradiation in initial 5 h. This work demonstrates that inorganic membrane integrated enzymatic catalysis and photocatalysis can be a powerful tool for different potential applications.