Increase In Reducing Sugars Research Articles

Optimization of conditions for production of pectinase in solid-state fermentation with Aspergillus flavus using dried Assam lemon peel powder as substrate

The culture conditions for pectinase production with Aspergillus flavus by solid-state fermentation (SSF) using dried Assam lemon peel were optimized and the pectinase was used for clarification of grape juice. A central composite rotatable design (CCRD) was used for optimization experiments with moisture content (50–90 %), incubation temperature (20–60 ℃), incubation time (96 h–192 h), and urea concentration (0–1 %) as independent variables, and pectinase activity as dependent variable. The optimum conditions for pectinase production obtained were moisture content of 60 %, incubation temperature of 50 ℃, incubation time of 96 h, and urea concentration of 0.30 % with a pectinase activity of 3.68 ± 0.20 U/mL where one unit of pectinase activity corresponds to number of µmole of galacturonic acid released in one minute in 1 % pectin solution at 37 °C and 4.8 pH. The crude pectinase was found to have maximum activity at a temperature of 40 ℃ and pH 4 and had an apparent Vmax and Km of 6.10 U/mL and 6.62 mg/mL respectively. The grape juice clarified using the crude pectinase showed decreased optical density (1.45 ± 0.06 to 1.17 ± 0.07) and viscosity (1.76 ± 0.10 to 1.46 ± 0.07 mPa.s) and increased reducing sugar content (13.90 ± 0.10 to 16.96 ± 0.06 g/100 mL juice), and total soluble solids (17.77 ± 0.16 to 18.50 ± 0.30 °Brix).

Process optimization and effect of different extraction methods on the characteristics and activities of Herba Patriniae polysaccharides: A correlation analysis

The process of papain assisted hot water (WP), cellulase assisted hot water (WC), papain mixed cellulase assisted hot water (WPC), ultrasonic assisted papain (PU), and ultrasonic assisted cellulase (CU) for Patriniae polysaccharides (HPs) extraction were optimized using the indicate of polysaccharide yield, respectively. Then, the physicochemical characteristics, antioxidant and hypoglycemic activities of HPs were compared, with an additional correlation analysis between the characteristics and activities of HPs. The results showed that CU demonstrated the highest extraction rate at 30.50 % among all methods. Compared to previous hot water extraction (HW), the enzyme-assisted extraction increased molecular weight, reducing sugar, mannose, and glucose content of HPs, while ultrasound-assisted extraction lowered mannose and glucose content of HPs, and increased reducing sugar content of HPs. All HPs showed concentration-dependent hypoglycemic and antioxidant activities. Correlation analysis revealed that HPs with moderate galactose content, higher reducing sugar, protein, glucose, mannose, xylose, and molecular weight polysaccharide content would exhibit superior hypoglycemic and antioxidant activities, with CU-HPs expressing these excellent characteristics. Together with the exceptional polysaccharide yield, CU was a promising strategy to extract HPs, whose optimum process were: enzyme addition 2.5 %, solid–liquid ratio 1:25, ultrasonic power 150 W, ultrasonic time of 50 min.

Functional Properties of Chitosan Oligomers Obtained by Enzymatic Hydrolysis.

The aims of this study were to obtain chitooligosaccharides (COS) from chitosan (CH) with improved functional properties and comparison of the use of two different enzymes: commercial cellulase (CL) and the dedicated enzyme chitosanase (CS). After enzymatic reaction, chitosan oligomers (NFs) were isolated by methanol into two fractions: precipitate (HMF) and supernatant (LMF). The occurrence of a hydrolysis reaction was confirmed by an increased reducing sugar content and viscosity reduction of chitosan oligomers. CPMAS 13C NMR analysis confirmed the dissimilar cleavage mechanism of the enzymes used. LMF and NF fractions were characterised by improved solubility in water (94.56%) compared to the HMF and CH samples (70.64%). Thermogravimetric analysis (TGA) showed that the HMF decomposed in two-stage process while CH, NF, and LMF decomposed in a three-stage process. The greatest mass loss of LMF samples (58.35%) suggests their sensitivity to high-temperature treatments. COS were a mixture of DP (degrees of polymerisation) from 3 to 18 hetero-chitooligomers, with an average Mw of <3 kDa. CL consisted of more low-DP products (DP 3-7) than COS made with CS. LMF characterised by DP~2 showed lower DPPH radical scavenging activity than HMF and NF with DP 3-7. The ability to reduce Escherichia coli increased in the given order: LMF > NF > HMF > CH.

Characterization, in vitro digestibility, antioxidant activity and intestinal peristalsis in zebrafish of Dioscorea opposita polysaccharides

The soluble crude polysaccharides from Dioscorea opposita (DOP1 and DOP2) were prepared and characterized. DOP1 and DOP2 obtained carbohydrate (65.71% and 70.18%, respectively), uronic acid (63.71% and 24.84%, respectively) and protein (8.09% and 9.51%, respectively) with molecular weight of 49.24 kDa and 21.62 kDa, respectively. DOP samples were mainly composed of mannose, glucose, galacturonic acid, galactose, and glucuronic acid. The digestibility in vitro, antioxidant activity and intestinal peristalsis effect were then investigated. DOP1 and DOP2 were degraded with decreased molecular weights (39.58 kDa and 18.56 kDa respectively), increased reducing sugar contents (from 16.95% to 19.27%; 12.45% to 15.50% respectively) and free monosaccharides (from 0.89% to 1.42%; 0.90% to 1.14% respectively) after gastric digestion. Both DOP1 and DOP2 were resistant to intestinal digestion, suggesting that DOP samples can be considered as a dietary fiber. Additionally, DOP1 and DOP2 exhibited antioxidant activities positively correlated with the concentration and remained the activities after gastrointestinal digestion in vitro. Furthermore, DOP reduced the fluorescence intensity significantly, indicating DOP can promote the intestinal peristalsis of zebrafish larvae (5 pdf) at 500 μg/mL. Therefore, DOP1 and DOP2 have a better functionality as dietary fibers, including antioxidant activity and intestinal peristalsis promotion, which can be developed as functional foods.

Influence of Enzymatic Hydrolysis on Composition and Technological Properties of Apple Pomace and Its Application for Wheat Bread Making.

The aim of this work was to evaluate the influence of enzymatic hydrolysis on dietary fiber, phenolic compounds and technological properties of apple pomace as wheat bread supplement. Apple pomace was hydrolyzed with Viscozyme® L, Pectinex® Ultra Tropical, Celluclast® 1.5L for 1 and 5h. Soluble (SDF) and insoluble (IDF) dietary fiber, reducing sugars and the total phenolic contents (TPC), along with the technological properties (water and oil retention capacities, solubility index, emulsion stability) of treated apple pomace were evaluated. The prebiotic activity of apple pomace water-soluble fraction on two probiotic strains Lactobacillus acidophilus DSM 20079 and Bifidobacterium animalis DSM 20105 was investigated. Treatment with Celluclast® 1.5L increased SDF, reducing sugars, SDF/IDF ratio and decreased IDF of apple pomace. While treatment with Viscozyme® L, Pectinex® Ultra Tropical increased reducing sugars, solubility index and TPC, but in most cases reduced oil and water retention capacities, decreased SDF and IDF content. All apple pomace extracts promoted growth of probiotic strains. Addition of 5% of apple pomace hydrolyzed with Celluclast® 1.5L did not have negative impact on wheat bread, while addition of other enzymatically hydrolyzed apple pomaces decreased pH, specific volume and porosity of wheat bread. Obtained results suggest that apple pomace enzymatically hydrolyzed with Celluclast® 1.5L can be potentially used for wheat bread supplementation with dietary fiber.

Application of a novel biological-nanoparticle pretreatment to Oscillatoria acuminata biomass and coculture dark fermentation for improving hydrogen production

BackgroundEnergy is the basis and assurance for a world's stable development; however, as traditional non-renewable energy sources deplete, the development and study of renewable clean energy have emerged. Using microalgae as a carbon source for anaerobic bacteria to generate biohydrogen is a clean energy generation system that both local and global peers see as promising.ResultsKlebsiella pneumonia, Enterobacter cloacae, and their coculture were used to synthesize biohydrogen using Oscillatoria acuminata biomass via dark fermentation. The total carbohydrate content in O. acuminata was 237.39 mg/L. To enhance the content of fermentable reducing sugars, thermochemical, biological, and biological with magnesium zinc ferrite nanoparticles (Mg-Zn Fe2O4-NPs) pretreatments were applied. Crude hydrolytic enzymes extracted from Trichoderma harzianum of biological pretreatment were enhanced by Mg-Zn Fe2O4-NPs and significantly increased reducing sugars (230.48 mg/g) four times than thermochemical pretreatment (45.34 mg/g). K. pneumonia demonstrated a greater accumulated hydrogen level (1022 mLH2/L) than E. cloacae (813 mLH2/L), while their coculture showed superior results (1520 mLH2/L) and shortened the production time to 48 h instead of 72 h in single culture pretreatments. Biological pretreatment + Mg-Zn Fe2O4 NPs using coculture significantly stimulated hydrogen yield (3254 mLH2/L), hydrogen efficiency)216.9 mL H2/g reducing sugar( and hydrogen production rate (67.7 mL/L/h) to the maximum among all pretreatments.ConclusionThese results confirm the effectiveness of biological treatments + Mg-Zn Fe2O4-NPs and coculture dark fermentation in upregulating biohydrogen production.

Effect of Cooking Method and Enzymatic Treatment on the in vitro Digestibility of Cooked and Instant Chestnut Flour.

Microwave treatment, roasting, boiling, and enzymatic treatment were used to prepare cooked and instant chestnut flour, and the in vitro digestibility were compared. Cooking gelatinized the starch and destroyed the granular and crystal structure, increasing starch digestibility. After enzymatic hydrolysis, starches were degraded by 20~24%, and the reducing sugar content of the instant flours increased by 79~94%. Starch digestibility was reduced after enzymatic hydrolysis, however, the estimated glycemic index (GI) increased to 65.1 ~ 77.7 due to the combined effect of increased reducing sugar and decreased starch hydrolysis in the instant flours. The chestnuts treated by 'boiling + enzymes' are still a medium GI food. These findings give guidance for the development of low GI cooked and instant chestnut flour.

Solid-state modification of tapioca starch using atmospheric nonthermal dielectric barrier discharge argon and helium plasma

Starch modification utilizes a substantial amount of water. This research aimed to investigate the effect of nonthermal dielectric barrier discharge (DBD) argon and helium plasma on tapioca starch's physicochemical properties and techno-functionality. Dry starch samples were treated with plasma generated from argon and helium gases at different voltage levels (10 and 15 kV) for 5, 10, and 15 min. The treatment did not destroy the starch’s crystalline structure, as evidenced by the birefringence under polarized light. Scanning electron micrographs showed dented starch granules. A marginal decrease in pH value of all treated samples was noted. A reduction in amylose and amylopectin molecular weight and increased reducing sugars were observed in the treated samples. Fourier transform infrared spectroscopy analysis showed a slight change in the 1047/1022 cm−1 absorbance ratio, indicating a change in short-range ordered degree of starch, while X-ray diffractometry showed a decrease in crystallinity. A significant reduction in peak viscosity, breakdown, and setback was observed. The gelatinized plasma-treated starch dispersion showed less shear-thinning and less thixotropic with increasing voltage and treatment times. This research proved that modification of starch in the solid-state using nonthermal plasma is feasible.

Characterization of scalded dough and its impact on the growth of mixed yeasts originating from Jiaozi

The use of scalded dough fermentation has become increasingly popular because of its positive effects on product texture, safe quality and flavor. In this study, the characteristics of scalded wheat dough and its influence on the evolution of mixed yeasts, namely Saccharomyces cerevisiae Y10, Wickerhamomyces anomalus Y13 and Torulaspora delbrueckii Y22 were investigated. Scalding water temperature above 90 °C significantly reduced the number of microorganisms. Bacillus spp. and some filamentous fungi survived the scalding process. Starch partially gelatinized during scalding, which resulted in the porous microstructure and increased reducing sugar content of dough. In the scalded dough with flour/boiling water ratio less than or equal to 1/1, the cell number of S. cerevisiae Y10 decreased from 6.5 log CFU/g dough to approximately 5.6 log CFU/g dough after 12 h of dough fermentation, but the W. anomalus Y13 and T. delbrueckii Y22 cell populations increased significantly (p < 0.05). When the flour/boiling water ratio was greater than 1/1, Y10 was the dominant yeast, and the inoculation ratio of the three yeasts had no effect on its dominant position in the fermented scalded dough. The results revealed the importance of controlling the scalding parameters when mixed yeast cultures were used in scalded dough fermentation.

Effects of gibberellin applications before flowering on the phenotype, ripening, and flavonoid compounds of Syrah grape berries.

Vitis vinifera L. cv. Syrah grapevines in most Chinese viticulture regions generally have compact clusters that increase the susceptibility to diseases and inhibit coloration of the inner berries. Gibberellic acid (GA3 ) is a plant growth regulator that is widely used during grape cultivation to elongate the rachis, control fruit set, and decrease cluster compactness. In this study, Syrah grapevines were treated with GA3 before flowering in 2019 and 2020 to determine the optimal GA3 treatment concentrations and times for decreasing bunch compactness, while minimizing the negative effects on the wine grape cluster weight. Pre-flowering GA3 applications at 3, 5, and 7mg L-1 , especially treatment at 20 days before flowering, decreased Syrah grape bunch compactness by decreasing the fruit set rate and promoting bunch elongation, with minimal adverse effects on the healthy grape cluster weight in both years. The 7mg L-1 GA3 treatment at 20 days before flowering significantly increased reducing sugar, total phenolic, tannin, and total anthocyanin contents of Syrah grape berries in 2019 and 2020. Moreover, high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry, hierarchical cluster, and principal component analysis results indicated GA3 applications before flowering (3, 5, and 7mg L-1 ) significantly affected the accumulation of different anthocyanins in Syrah grape berries. Notably, the application of 7mg L-1 GA3 at 20 days before flowering resulted in the highest anthocyanin content. Pre-flowering gibberellin application can decrease bunch compactness and improve the quality of Syrah grape berries. These findings reflect the potential utility of gibberellin treatments for decreasing cluster compactness and increasing the quality of wine grapes. © 2022 Society of Chemical Industry.

Effects of Biodegradable Liquid Film on Cabernet Sauvignon (V. vinifera L.) Grape Quality

Biodegradable liquid film (BLF) improves soil structure and increases plant freezing tolerance after spraying on the surface of soil and plant. In this study, the effects of BLF on grape composition and volatile compounds in Cabernet sauvignon (Vitis vinifera L.) grapes were determined by spraying BLF during the dormant periods over three years. The aim of the study was to evaluate the potential impact of BLF as an overwintering protection measure on grape fruit quality. In 2020 and 2021, BLF spraying increased reducing sugar content and 100-berry weight, decreased titratable acid content, and improved the maturity factor. Compared with the vines not sprayed with BLF, the content of total phenols and total anthocyanins in grape skins showed an increase over the three-year period, with the largest increases of 31.92% and 48.38%, respectively, and the content of total tannins and total flavan-3-ols increased in 2020 and 2021. BLF treatment also increased the total phenolic content in seeds for all three years, reaching a significant level in 2019, 16.38% higher than control treatment (CK). HPLC analysis showed that BLF treatment affected the content and composition of monomeric anthocyanins in grape skins, especially in 2021, BLF treatment significantly increased the content of nine monomeric anthocyanins, and the proportion of acetylated and coumaroylated anthocyanins. However, GC-MS analysis indicated that BLF had little effect on volatile compounds. These results suggest that BLF can be used as an overwintering protection measure in cold regions to promote the accumulation of sugars and polyphenolics, thereby improving overall grape quality.

Yeast and enzymatic hydrolysis in converting Chlorella biomass into hydrogen gas by Rhodobacter sp. and Rhodopseudomonaspalustris

Enhanced hydrogen evolution was pursued in this work. Rhodobacter sp. (Rb) and Rhodopseudomonas palustris (Rp), single or mixed were used to extract hydrogen molecules from Chlorella fusca biomass. To elevate their fermentable contents, Chlorella was grown at nitrogen and/or phosphorus deprivation. Besides, cellulase and/or macerozyme, Triton X100 or sonicated yeast were applied for further biohydrogen fermentation. Utilizing hydrolysates of mineral deprived Chlorella cultures, Rb exhibited relatively higher cumulative hydrogen (4200 ml L−1) than Rp (2500 ml L−1) while mixed cultures attained significantly higher levels (4700 ml L−1). Triton or enzymes significantly enhanced hydrogen evolution, with more effectiveness of macerozyme than cellulase. A novel use of sonicated yeast, as enzymes pool, induced the highest significant collective H2 (up to 47 times that of microalgal supernatant). Sonicated yeast induced a remarkable hydrolysis of algae, as inferred from increased reducing sugars. However, hydrogen evolution efficiency exhibited poor proportionality with reducing sugars, indicating fermentation of other metabolites.

Interferences of Waxes on Enzymatic Saccharification and Ethanol Production from Lignocellulose Biomass.

Wax is an organic compound found on the surface of lignocellulose biomass to protect plants from physical and biological stresses in nature. With its small mass fraction in biomass, wax has been neglected from inclusion in the design of the biorefinery process. This study investigated the interfering effect of wax in three types of lignocellulosic biomass, including rice straw (RS), Napier grass (NG), and sugarcane bagasse (SB). In this study, although small fractions of wax were extracted from RS, NG, and SB at 0.57%, 0.61%, and 1.69%, respectively, dewaxing causes changes in the plant compositions and their functional groups and promotes dissociations of lignocellulose fibrils. Additionally, dewaxing of biomass samples increased reducing sugar by 1.17-, 1.04-, and 1.35-fold in RS, NG, and SB, respectively. The ethanol yield increased by 1.11-, 1.05-, and 1.23-fold after wax removal from RS, NG, and SB, respectively. The chemical composition profiles of the waxes obtained from RS, NG, and SB showed FAME, alcohol, and alkane as the major groups. According to the conversion rate of the dewaxing process and ethanol fermentation, the wax outputs of RS, NG, and SB are 5.64, 17.00, and 6.00 kg/ton, respectively. The current gasoline price is around USD 0.903 per liter, making ethanol more expensive than gasoline. Therefore, in order to reduce the cost of ethanol in the biorefinery industry, other valuable products (such as wax) should be considered for commercialization. The cost of natural wax ranges from USD 2 to 22 per kilogram, depending on the source of the extracted wax. The wax yields obtained from RS, SB, and NG have the potential to increase profits in the biorefining process and could provide an opportunity for application in a wider range of downstream industries than just biofuels.

Covalent Immobilization of Chondrostereum purpureum Endopolygalacturonase on Ferromagnetic Nanoparticles: Catalytic Properties and Biotechnological Application.

Pectinases are widely used in a variety of industrial processes. However, their application is limited by low catalytic processivity, reduced stability, high cost, and poor re-use compatibility. These drawbacks may be overcome by enzyme immobilization with ferromagnetic nanoparticles, which are easily recovered by a magnetic field. In this work, an endopolygalacturonase from Chondrostereum purpureum (EndoPGCp) expressed in Pichia pastoris was immobilized on glutaraldehyde-activated chitosan ferromagnetic nanoparticles (EndoPGCp-MNP) and used to supplement a commercial enzyme cocktail. No significant differences in biochemical and kinetic properties were observed between EndoPGCp-MNP and EndoPGCp, although the EndoPGCp-MNP showed slightly increased thermostability. Cocktail supplementation with EndoPGCp-MNP increased reducing sugar release from orange wastes by 1.8-fold and showed a synergistic effect as compared to the free enzyme. Furthermore, EndoPGCp-MNP retained 65% of the initial activity after 7 cycles of re-use. These properties suggest that EndoPGCp-MNP may find applications in the processing of pectin-rich agroindustrial residues.

Composite Films of Thermoplastic Starch and CaCl2 Extracted from Eggshells for Extending Food Shelf-Life

Calcium chloride (CaCl2) has been widely used to maintain the quality of fresh-cut fruits and vegetables because it stabilizes and strengthens the membrane system against fungal attacks. It is mainly applied via spray coating and dip coating techniques. This study explored a method of incorporating calcium chloride extracted from eggshells in a packaging material, thermoplastic starch (TPS), via a hot-melt extrusion process. The composites were characterized by FTIR, DSC, SEM-EDX and tensile testing. FTIR confirmed the chemical reactions between CaCl2 and TPS. DSC results showed a significant decrease in the heat of fusion by adding 20 wt% of CaCl2 content in TPS, indicating a drop in the degree of crystallinity. The Young’s modulus of TPS was not significantly affected by the incorporation of 10 wt% CaCl2 (P = 0.968), but reduced notably with the addition of 20 wt% CaCl2 (P = 0.05), indicating the plasticizer effect of the CaCl2. Physiochemical analysis of fresh-cut apple slices was assessed. Samples placed on the surface of the TPS/CaCl2 composites displayed less pH reduction, reduced antioxidant activity, more weight loss and increased reducing sugar compared to the samples placed on the surface of virgin TPS films. CaCl2 released from the TPS/CaCl2 films was measured and their antimicrobial activity was confirmed by bacterial inhibitory growth assessment. Fungal growth was observed on apple slices placed on virgin TPS film by day 21 while apple slices placed on TPS/CaCl2 20 wt% composites did not support any fungal growth for 28 days. In summary, TPS and eggshell-extracted CaCl2 showed the ability to maintain the quality of fresh-cut apples, and TPS/CaCl2 10 wt% composite could be a good option as a packaging material for fresh-cut fruits due to active antimicrobial activity and maintained Young’s modulus.

Shelf-Life of Bunched Carrots as Affected by Nitrogen Fertilization and Leaf Presence

Nitrogen (N) fertilization is essential for adequate earliness and the commercial attractiveness of carrots, but its excess could generate fast decay during postharvest, mostly in bunched carrots exhibiting their highly perishable leaves. A field experiment was conducted over the 2016–2017 growing season to address the effects of two N fertilization rates (120 and 240 kg N ha−1, hereafter N120 and N240, respectively) and leaf presence/absence (leaf+ and leaf−) on physicochemical and compositional traits of carrots cv. ‘Dordogne’, after storage at 4.0 ± 0.5 °C, 95–96% relative humidity (RH) for 0, 3, 6, 12, and 24 days (hereafter S0–S24). Before storage, carrots were arranged in bunches and packaged in common low-density polyethylene (LDPE) pouches (thickness 95 μm), 54 × 24 cm size, with 16 holes of 5 mm size. N240 carrots compared to N120 showed higher cumulative weight loss (CWL) and firmness reduction, with differences at S24 equal to 108 vs. 41 g kg−1 fresh weight (FW) and 13.3 vs. 14.5 N, respectively. N240 compared to N120 increased also the color deviation (ΔE*ab, +126%) and nitrates content (+93%) of carrots and slowed down their temporal increase of total polyphenols and antioxidant activity. Leaf+ carrots compared to leaf boosted CWL and firmness reduction, with differences at S24 equal to 90 vs. 58 g kg−1 FW and 12 vs. 17 N, respectively. In addition, leaf presence increased reducing sugars (+17%) and decreased nitrates (−24%) contents. This research has shown the possibility of improving the desirable quality and shelf-life of carrots by halving the N dose commonly supplied by growers and marketing bunched carrots within 12 days from the start of storage.

Efficient bioconversion of sugarcane tops biomass into biofuel-ethanol using an optimized alkali-ionic liquid pretreatment approach

Sugarcane tops (SCT) may be an imperative lignocellulosic feedstock for production of renewable energy in view of ever-rising global energy demands. The current study presents the first ever report of combinative pretreatment of sugarcane tops biomass using ionic liquid (1-ethyl-3-methylimidazolium chloride) and alkali (ammonium carbonate) for effective and enhanced saccharification. The enzymatic hydrolysis of combinatorially pretreated SCT biomass resulted in a significantly higher reducing sugar yield (172.34 mg/g biomass) as compared to that obtained after standalone IL (85.9 mg/g biomass) or alkali pretreatment (102.6 mg/g biomass). The saccharification enzymes (cellulase/xylanase) used for hydrolysis of pretreated SCT biomass were in-house produced from an IL-tolerant, newly isolated fungus Penicillium chrysogenum VS4. Optimization of process variables for combined pretreatment was accomplished based on design of experiments, and enhanced reducing sugar yield was obtained. The experimental design for ascertaining optimal level of process variables, i.e., biomass loading (5.33%, w/w), temperature (100 °C), and time (4.50 h) was validated. Optimization of the process parameters resulted in 25.27% increased reducing sugar yield (215.89 mg/g biomass) as compared to that under unoptimized process. Ultrastructural analysis of SCT biomass after combined pretreatment was investigated by scanning electron microscopy and Fourier transform infrared spectroscopy which indicated that the biomass had undergone drastic alterations and substantial disintegration due to pretreatment. The current study highlights the potential of combinative pretreatment strategy for efficient conversion of SCT biomass. Such combined pretreatment approaches may be extended to other biomass feedstocks as well for developing successful biorefineries.

Development of consolidated bioprocess for biofuel-ethanol production from ultrasound-assisted deep eutectic solvent pretreated Parthenium hysterophorus biomass

A novel consolidated bioprocess was designed for processing of Parthenium hysterophorus biomass based on ultrasound-assisted deep eutectic solvent (DES) pretreatment followed by in situ enzymatic saccharification and fermentation of sugars to ethanol-biofuel. Among various DESs examined, choline chloride/sorbitol (CCS, molar ratio 1:5) pretreated P. hysterophorus biomass yielded maximum sugar (148.54 mg/g biomass) upon enzymatic saccharification. Furthermore, combined ultrasonic irradiation and CCS pretreatment resulted in substantially enhanced sugar yield as compared with either of the standalone pretreatment. A central composite design was employed for the optimization of combined ultrasound and choline chloride/sorbitol pretreatment that further aided in achieving increased reducing sugar yield (25.72%). The pretreated biomass was examined by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and proton nuclear magnetic resonance (1H-NMR) analysis to elucidate the functional mechanisms of combinative pretreatment. Understanding of pretreatment mechanisms may help custom designing of novel strategies for the efficient refining of biomass.

Alleviating product inhibition of Trichoderma reesei cellulase complex with a product-activated mushroom endoglucanase

Product inhibition of cellulase is a challenging issue in industrial processes. Here, we introduced a product-activated mushroom cellulase, PaCel3A from Polyporus arcularius, into Trichoderma reesei. The filter paper activity, carboxymethyl cellulase activity, and saccharification efficiency (substrate: pretreated rice straw, PRS) of transformants increased significantly with this enzyme (by 18.4–26.8%, 13.8–22.8%, and 17.0%, respectively). A mutant of PaCel3A, PaCel3AM, obtained based on B-factor analysis, saturated mutagenesis, and residual activity assay, showed improved thermostability. The PRS saccharification efficiency using the cellulase complex from T. reesei transformants overexpressing pacel3am increased by 56.4%–63.0%. In addition, the T. reesei cellulase complex obtained by adding the purified recombinant PaCel3AM from T. reesei (rCel3aM-tr) to hydrolyze PRS resulted in increased reducing sugar yields at all sampling points, outperforming the cellulase complexes without rCel3aM-tr. These results suggest that introducing product-activated cellulase genes is a simple and feasible method to alleviate the product inhibition of cellulase.

Effect of ultrasonic treatment on sucrose inversion in vegetable and fruit purees

Relevance.This article presents the results of a study of the process of sucrose inversion in vegetable and fruit monocomponent purees with and without sucrose under the influence of ultrasonic action on them.Methods.For the study, experimental samples of carrot, pumpkin and Apple puree of two types were made – a monocomponent natural puree (without sugar) and puree with the addition of 5% sucrose (by weight). The main part of the study was to study the depth of sucrose inversion in experimental samples, depending on the specified parameters of ultrasound exposure at a frequency of 21.6 kHz for 30 minutes on a laboratory cavitation unit in a flow-through cyclic mode.Results.It was found that in all experimental samples, the amount of total reducing sugars increased significantly compared to the values obtained in control samples that were not subjected to ultrasonic treatment. So, in natural apple puree (without adding sucrose) after ultrasound exposure, an increase in total reducing sugars was detected by 9.3%, and in experimental samples of apple puree with added sucrose – by 10.9%, in relation to control samples, which is 1.2 times higher than in natural puree. In samples of carrot puree (without adding sucrose), the increase in total reducing sugars was 6.7%, and in puree with added sucrose, the increase was 12.2%, which is 1.8 times higher than the inversion in puree without sugar. In samples of pumpkin puree without sugar, the increase in reducing sugars was 4.2%, and in samples with added sucrose – 9.9%, i.e. 2.4 times higher than in samples without sugar.These data allow us to conclude that ultrasound exposure can intensify the inversion of sucrose with an increase in the number of reducing sugars, and this process takes place more deeply in products containing added sucrose.