Enzyme Dosage Research Articles

Phytase Enzyme Improves Growth Performance and Body Chemical Composition of Sangkuriang Catfish (Clarias gariepinus var. Sangkuriang) Juvenile

Due to their nutritional value, alternative vegetable materials such as soybean are needed to promote sustainable aquaculture development. However, phytate in soybean could interfere with the protein digestion of the fish body. This study examines the effectiveness of phytate enzymes in enhancing protein digestibility, growth performance, mineral digestion, and body chemical composition of Sangkuriang catfish (Clarias gariepinus var. Sangkuriang) juveniles. The study was completely randomized design with 4 treatments and 3 repetitions. One hundred thirteen Sangkuriang catfish juveniles (7.65 ± 0.14 g) were used for each repetition. The fish were fed with an experimental diet supplemented with various doses of phytase enzyme: 0 (A), 500 (B), 1,000 (C), and 1,500 (D) FTU/kg of feed. The mineral digestibility, protein digestibility, protein efficiency ratio (PER), feed conversion ratio (FCR), the efficiency of feed utilization (EFU), apparent digestibility coefficients (ADCp), relative growth rate (RGR), and survival rate (SR) were observed. Data were analyzed using analysis of variance followed by Duncan’s multiple range test. The results showed that adding 1,000 FTU/kg of phytase enzyme (C) exhibited the highest PER, FCR, EFU, ADCp, and RGR value of Sangkuriang catfish juveniles compared to other treatments. All treatment groups (B-C) had the same SR value (100%) and had the highest crude protein and ash content compared to the A group. All group treatments also exhibited a higher phosphorus, calcium, potassium, magnesium, iron, zinc, manganese, copper, and cobalt. Therefore, phytase enzyme supplementation could improve protein digestibility, mineral digestibility, growth performance, and body chemical composition of Sangkuriang catfish juveniles.

Isolation, Identification, and Biological Activity Analysis of Swim Bladder Polypeptides from Acipenser schrencki.

Swim bladder polypeptides (SBPs) of Acipenser schrencki were analyzed for their antioxidant activity and physicochemical properties. The results showed the optimal enzymatic conditions were alkaline protease with a solid-to-liquid ratio of 1:20, an incubation time of 4 h, a temperature of 55 °C, and an enzyme dosage of 5000 U/g. Three different molecular weight fractions (F1, F2, and F3) were obtained via ultrafiltration. F3 (912.44-2135.82 Da) showed 77.90%, 72.15%, and 66.25% removal of O2•-, DPPH•, and •OH, respectively, at 10 mg/mL, which was significantly higher than the F1 and F2 fractions (p < 0.05). F3 contained proline (6.17%), hydroxyproline (5.28%), and hydrophobic amino acids (51.39%). The UV spectrum of F3 showed maximum absorption at 224 nm. Peptide sequence analysis showed that F3 contained antioxidant peptides (MFGF, GPPGPRGPPGL, and GPGPSGERGPPGPM) and exhibited inhibitory activities on angiotensin-converting enzyme and dipeptidyl peptidase III/IV (FRF, FPFL and LPGLF). F3 was considered a good raw material for obtaining bioactive peptides.

Acid–Base Pretreatment and Enzymatic Hydrolysis of Palm Oil Mill Effluent in a Single Reactor System for Production of Fermentable Sugars

Palm oil mill effluent (POME) is one of the main agro-industrial wastewaters in Malaysia. Highly polluting POME is a serious threat to the environment. In recent years, the methods used to treat POME are inefficient and complex in terms of cost or environmental preservation. The main object of this research is to propose a single reactor system (SRS) obtained from POME wastewater discharge as a promising low-cost treatment and high-energy method for harvesting the fermentable sugar by applying acid–base–enzyme pretreatment and hydrolysis of POME by locally produced cellulase enzymes to enhance biofuel production. Several experiments were conducted to produce fermentable sugars through the statistical methods, including the characterization of POME, acid-base pretreatment, and enzymatic hydrolysis process for reducing sugar production. The one-factor-at-a-time (OFAT) results showed that the highest reducing sugar yield, 23.5 mg/mL of POME, was achieved by enzymatic hydrolysis in an SRS without having a separation and purification. Based on OFAT performance, optimization of two factors such as substrate concentration (total suspended solids, TSS %w/v) and enzyme loading (μmol/min) was carried out by applying face-centered central composite design (FCCCD) under the response surface methodology (RSM) to develop a second-order regression model. The optimum reducing sugar production was 26.6 mg/mL (53.14%) with the conditions of 5% w/v, TSS, and 80 μmol/min/mL of the enzyme dose. In addition, the results of this research can be further considered in biofuel production using other wastewaters to enhance biofuel production as well as wastewater treating functions and minimize the negative environmental impacts.

Effects of exogenous protease addition on fermentation and nutritive value of rehydrated corn and sorghum grains silages

The study objective was to evaluate the effects of the addition of exogenous protease on the fermentation and nutritive value of rehydrated corn and sorghum grain silages during various storage periods. Treatments were applied using a 2 × 6 × 3 factorial combination, with 2 types of rehydrated grains (corn and sorghum), 6 doses of the enzyme (0, 0.3, 0.6, 0.9, 1.2, and 1.5%, based on natural matter) and 3 fermentation periods (0, 60, and 90 days) in a completely randomized design, with 4 replications. The protease aspergilopepsin I, of fungal origin, produced by Aspergillus niger, was used. The lactic acid concentration increased linearly as the enzyme dose increased in corn (CG) and sorghum (SG) grain silages, at 60 and 90 days of fermentation. There was an increase in the concentrations of ammonia nitrogen and soluble protein, as well as the in situ starch digestibility in rehydrated CG and SG silages, compared to the treatment without the addition of protease. The addition of 0.3% exogenous protease at the moment of CG ensiling and 0.5% in rehydrated SG increased the proteolytic activity during fermentation, providing an increase in in situ starch digestibility in a shorter storage time.

A comparison of ultrasonic, ozone, and enzyme pre-treatments on cheese whey degradation for enhancement of anaerobic digestion

Lactose in cheese whey wastewater (CWW) makes it difficult to degrade under normal conditions. The effect of ultra-sonication (US), ozonation and enzymatic hydrolysis on increasing the bioavailability of organic matter in CWW and biogas production were evaluated. The pre-treatment conditions were: specific energy input varied from 2130 to 8773KJ/KgTS for a sonication time of 4.5–18.5 min, Ozone (O3) dosages ranging from 0.03 to 0.045gO3/gTS were applied for 4–16 min, pH (3.8–7.1), temperature (35°C–55°C), enzyme dosage (0.18–0.52%), was operated from 7.75 to 53 min for enzymatic hydrolysis by β-galactosidase. The results of the US reported a maximum sCOD solubilisation of 77.15% after 18.5 min of operation, while the corresponding values for ozonation and enzymatic methods were 64.8% at 16 min and 54.79%, respectively. The organic matter degradation rates evaluated in terms of protein and lactose hydrolysis were 68.78%,46.03%; 47.83%,16.15% and 54.22%,86.2%respectively, for US, ozonation and enzymatic methods. The cumulative methane yield for sonicated, ozonised and enzymatically hydrolysed samples were 412.4 ml/g VS, 361.2 ml/g VS and 432.3mlCH4/gVS, respectively. Regardless of the lower COD solubilisation rates attained, enzymatic pre-treatment showed maximum methane generation compared to US and ozonation. This could be attributable to the increased activity of β-galactosidase in hydrolysing whey lactose. The energy calculations revealed that the pre-conditioning of organic-rich CWW with enzymatic hydrolysis is more effective and efficient, yielding a net energy gain (gross output energy-input energy) of 9166.7 KJ and an energy factor (ratio of output to input energy) of 6.67. The modified Gompertz model well simulated all experimental values.

A sequential combination of advanced oxidation and enzymatic hydrolysis reduces the enzymatic dosage for lignocellulose degradation

High cellulase cost is a significant challenge to reducing the production cost of the lignocellulosic ethanol industry. Fenton reagents can oxidize and degrade organic matter through the advanced oxidation process. This study combined the Fenton reagent with cellulase to improve lignocellulose degradation efficiency and reduce the amount of enzyme dosage. Fenton reaction studies showed that the experimental group of 1000 mmol/L H2O2 + 10 mmol/L FeSO4 was the most suitable condition for coupled cellulase hydrolysis and excessive reagents might cause a decrease in the promotion effect. The solid loading analysis evidenced that the lignocellulose degradation can be facilitated by the Fenton reagent in the 15%–30% solids range. Treated with the Fenton reagent, the release of free water and the increase of specific surface area in the degradation process were enhanced. It's indicated that the amount of cellulase decreased by 76.2% under the combination of advanced oxidation and enzymatic hydrolysis. The techno-economic analysis of 300,000 t/a lignocellulosic ethanol showed that the combination reduced 26.96% annual costs. These results confirmed that the method of combining advanced oxidation with enzymatic hydrolysis is an effective way to improve the economics of industrial ethanol.

Polyethyleneimine-MOF composite as a support for immobilization of lipase with enhanced activity in kinetic resolution

Lipase PS from Pseudomonas cepacia was steadily immobilized on a new support prepared with metal-organic framework (MOF) and polyethyleneimine (PEI) through a PEI-boosted strategy (PS@MOF-5-PEI). Evaluated by the enantioselective transesterification reaction of racemic 1-(4-(trifluoromethyl) phenyl) ethanol (TFMP) with vinyl acetate, PS@MOF-5-PEI expressed more than 10 times of increase in specific activity (U/mg protein) compared with free lipase PS. PS@MOF-5-PEI had an enhanced enzyme-substrate affinity and catalytic efficiency than free lipase PS, as supported by a lower apparent Km value (7.3 vs 11.3 mM) and an increased Vmax/Km value (0.38 vs 0.05 min−1), respectively. Under the optimal conditions involving 45 °C, substrate ratio of 1:18, enzyme dosage of 20 mg and reaction time of 60 min, the ees of 99.8% and c of 50.1% for kinetic resolution of TFMP enantiomers were achieved with PS@MOF-5-PEI, which can be recycled for 10 times without significant loss in activity and with enantioselectivity well maintained.

Carbonic Anhydrase Enhanced UV-Crosslinked PEG-DA/PEO Extruded Hydrogel Flexible Filaments and Durable Grids for CO2 Capture.

In this study, poly (ethylene glycol) diacrylate/poly (ethylene oxide) (PEG-DA/PEO) interpenetrating polymer network hydrogels (IPNH) were extruded into 1D filaments and 2D grids. The suitability of this system for enzyme immobilization and CO2 capture application was validated. IPNH chemical composition was verified spectroscopically using FTIR. The extruded filament had an average tensile strength of 6.5 MPa and elongation at break of 80%. IPNH filament can be twisted and bent and therefore is suitable for further processing using conventional textile fabrication methods. Initial activity recovery of the entrapped carbonic anhydrase (CA) calculated from esterase activity, showed a decrease with an increase in enzyme dose, while activity retention of high enzyme dose samples was over 87% after 150 days of repeated washing and testing. IPNH 2D grids that were assembled into spiral roll structured packings exhibited increased CO2 capture efficiency with increasing enzyme dose. Long-term CO2 capture performance of the CA immobilized IPNH structured packing was tested in a continuous solvent recirculation experiment for 1032 h, where 52% of the initial CO2 capture performance and 34% of the enzyme contribution were retained. These results demonstrate the feasibility of using rapid UV-crosslinking to form enzyme-immobilized hydrogels by a geometrically-controllable extrusion process that uses analogous linear polymers for both viscosity enhancement and chain entanglement purposes, and achieves high activity retention and performance stability of the immobilized CA. Potential uses for this system extend to 3D printing inks and enzyme immobilization matrices for such diverse applications as biocatalytic reactors and biosensor fabrication.

Silver Carp (Hypophthalmichthys molitrix) Scales Collagen Peptides (SCPs): Preparation, Whitening Activity Screening and Characterization

This study involves the preparation of scale collagen peptides (SCPs) with whitening activity from silver carp (Hypophthalmichthys molitrix) and their characterization and peptide sequence identification. In this article, scanning electron microscopy (SEM) was used to observe structure changes of sliver carp scales; enzymatic hydrolysis was optimized through protease screening and response surface optimization. The ultrafiltration was used to separate SCPs and the whitening activity was comprehensively evaluated using radical scavenging rate and tyrosinase-inhibiting activity, among others. An optimal component was characterized and identified using various modern spectral analysis techniques. The results showed that the surface of silver carp scales after decalcification was smooth and clear. The pepsin had the highest peptide yield and tyrosinase-inhibiting activity (90.01% and 82.25%, respectively). The optimal enzymatic hydrolysis conditions were an enzyme dosage of 16.1%, a solid-liquid ratio of 1:15.6 and a time of 4.9 h. The proportions of hydrophobic and basic amino acids in the peptide composition were 32.15% and 13.12%, respectively. Compared with SCPs2, SCPs1 (6096.68-9513.70 Da) showed better ·OH scavenging ability, tyrosinase-inhibiting activity and moisture absorption. SCPs1 was a macromolecular fragment of type I collagen with a triple helix structure, containing three peptide sequences with the potential for tyrosinase activity inhibition (AGPPGADGQTGQRGE, SGPAGIAGPAGPRGPAGPNGPPGKD and KRGSTGEQGSTGPLGMRGPRGAA). These results show that SCPs1 is a collagen peptide product with whitening potential.

How macronutrients and pancreatic enzyme supplements dose variability affect fat, protein and starch absorption in children with cystic fibrosis.

low evidence on the dose of enzymatic supplements used in pancreatic enzyme replacement therapy (PERT) is available. assessing if fat, protein and starch absorption could be related to the dose of the enzymatic supplement, the intra-patient variability in the dose and macronutrient intake. Four-day food records and 3-day faecal samples were prospectively collected in 69 children with cystic fibrosis. Pearson correlations between enzyme dose and macronutrient absorption, and beta regression models were applied to explain the results. the supply of protease units per protein intake (PU/g protein) in relation to lipase units per fat intake (LU/g fat) was low and the intra-patient variability in the dose of enzymes was ±1331 LU/g fat. Fat and starch absorption was >90% while for protein it was 81.5%. The coefficient of fat absorption was associated with an interaction between the dose of LU/g fat and its variability among different days. Lipid and protein intake were also determinants of the coefficient of fat absorption. the dose of PERT should be re-adjusted to the amount of dietary fat of every meal (constant LU/g fat) to minimize variability and increase fat absorption. Also, the supply of protease should be increased to prevent from protein malabsorption.

Distinct lignocellulolytic enzymes produced by Trichoderma harzianum in response to different pretreated substrates

In order to optimize the composition of enzyme cocktail for improving the hydrolytic efficiency of lignocellulose, different substrates were tested as inducers for producing lignocellulolytic enzymes by Trichoderma harzianum EM0925 in this study. As results, ultrafine grinding or steam explosion pretreated substrates can induce T. harzianum EM0925 to secret holo lignocellulolytic enzymes; acid treated substrate can induce cellobiohydrolase; while alkali or sodium chlorite treated substrates can induce β-xylosidase specifically. Furthermore, the combination of enzyme cocktails with different hydrolysis characteristics can further improve the hydrolysis efficiency, since 100% yields of glucose and xylose were obtained simultaneously from ultrafine grinding treated corn stover at low enzyme dosage (1.2 mg proteins/g substrate). This study for the first time demonstrated an effective solution that specific-pretreated substrates can be used as inducers for specific enzyme production by T. harzianum, which provided new idea and potential strategy for the construction of highly-efficient lignocellulolytic enzyme cocktails.

Improvement of Asterarcys quadricellulare biomass solubilization and subsequent biogas production via pretreatment approaches: structural changes and kinetic modeling evaluation.

This study investigated the effect of enzymatic and hydrothermal pretreatment approaches on the solubilization of organic matter, structure, and biogas yield from microalgal biomass. The soluble chemical oxygen demand (sCOD) concentration increased by 1.21-3.30- and 5.54-6.60-fold compared to control by enzymatic and hydrothermal pretreatments respectively. The hydrothermal pretreatment affected the structural changes in the microalgal biomass markedly; nonetheless, increased enzymatic concentration also had a definite effect on it as determined by qualitative approaches like scanning electron microscopy and Fourier transform infrared spectroscopy. Also, the hydrothermal pretreatment (100°C for 30min) resulted in the highest biogas production potential (P) of 765.37 mLg-1 VS at a maximum biogas production rate (Rm) of 22.66 mLg-1day-1 with a very short lag phase (λ) of 0.07days. The biogas production of pretreated microalgal biomass particularly at higher enzyme dose (20%, 24h) and higher hydrothermal pretreatment temperature (120°C, 30min) showed a significant but weak correlation (R = 0.53) with sCOD, thus demonstrating that the less organic matter was used up for the biogas production. The modified Gompertz model explained the anaerobic digestion of microalgal biomass more accurately and had a better fit to the experimental data comparatively because of the low root mean square error (3.259-16.728), residual sum of squares (78.887-177.025), and Akaike's Information Criterion (38.605-62.853).

Recent advances in substrate-enzyme interactions facilitating efficient biodegradation of lignocellulosic biomass: A review

Lignocellulosic biorefinery has long been recognized as a potential strategy for sustainable production of biofuels, materials and chemicals. These productions in many cases rely on pretreatment and enzymatic hydrolysis of lignocellulosic carbohydrates, whereas the low degradation efficiency and high enzyme dosage are challenging bottlenecks of economically industrial production. The complex recalcitrant nature of lignocellulose requires a well-matched enzyme cocktail to achieve complete and efficient degradation. Numerous studies have investigated the relationship between biomass components, structural properties and enzymes synergistic action in the past decades. This article aims to present a comprehensive review on this subject by introducing recent advances in substrate modification techniques, underlying mechanisms of enzyme synergism and governing factors in structure-activity interaction. In addition, newly developed modellings and multi-omic analysis techniques for preparing commercial enzyme preparations are introduced, revealing possible avenues for achieving economic viability of lignocellulose bioconversion.

Status of TG enzyme modified fish gelatin

TG enzyme can catalyze the ligation reaction (glycosylation reaction), crosslinking reaction and deamination reaction between or within proteins, and has great application potential in the food field. TG enzyme was used as coagulant to modify fish gelatin, and the effects of crosslinking temperature, pH, TG enzyme dosage, gelatin concentration and crosslinking time on the characteristics of fish gelatin gel were discussed.

Permeabilization of the cell wall of Chlorella sorokiniana by the chitosan-degrading protease papain

To enhance the nutritional value of Chlorella microalgae for use in food and feed, it is crucial to improve the bioavailability of nutrients and bioactive compounds from whole-cell biomass in a cost-effective manner. In this study, papain – a plant-derived cysteine protease with additional chitosanase-like activity – was applied to partially degrade the cell wall of Chlorella sorokiniana at ambient temperature, whereas the cell wall of the closely related species Chlorella vulgaris remained unaffected and generally appeared more stable. Three commercial enzymes - cellulase, lysozyme and papain - were evaluated for their suitability to digest the fresh C. sorokiniana and C. vulgaris biomass suspended in acetate buffer at pH 4.8. The accessibility of algal carotenoids to acetone extraction, performed on analytical scale, proved to be a simple and reliable measure for the degree of cell wall degradation, while on the contrary the enzyme-induced release of reducing sugars did not strictly correlate with the actual permeabilization of the cell. Ultimately, papain was found to be more active than lysozyme, while cellulase showed almost no effect. This is in line with the knowledge about the C. sorokiniana cell wall composition with regard to its framework of chitosan-like fibers and high protein content. Papain concentration, enzyme-to-biomass ratio and duration of the enzyme treatment were varied. Papain was equally efficient in acidified BG11 medium, therefore enzymatic permeabilization of the cell wall directly after harvesting the microalgae seems possible– either for valorization of whole-cell biomass or as an energy-efficient process step to increase yields in biorefinery approaches. Main drawback of the approach is the high enzyme dose of estimated 5 g papain per 100 g of C. sorokiniana dry mass, that was needed to gain sufficient effect. Future research is required to optimize dosage in combination with synergistically acting enzymes and under the conditions of the actual application.

Remarkable improvement in the storage stability of maltodextrin through 1,4-α-glucan branching enzyme modification

Enzymatic modification is a potential approach to effectively improve the stability of maltodextrin for food and industrial applications. In this study, a 1,4-α-glucan branching enzyme from Rhodothermus obamensis STB05 (Ro-GBE) was used to modify maltodextrin. The transparency of the Ro-GBE-modified maltodextrin prepared under the optimal modification conditions: enzyme dosage of 100 U/g, reacting time of 12 h at 55 °C, and pH of 7.0, was maintained above 90% for over 30 days. In addition, the viscosity stability, retrogradation property, and freeze–thaw stability were significantly improved. Because of the constant value of the dextrose equivalent (DE), increase in α-1,6-glycosidic linkage ratio, and decrease in weight-average molecular mass (Mw), we believed that the glycosidic bond rearrangement played a vital role in the Ro-GBE modification. Moreover, Ro-GBE exhibited high specificity in cleaving long chains with DP ≥ 15 and transferring the released chains as exterior chains to form a short-clustered structure. Pearson correlation analysis revealed that the transparency stability of maltodextrin mainly correlated with the branching degree, while the viscosity stability, retrogradation property, and freeze–thaw stability mainly contributed to the Mw of branched molecules.

Eighteen Novel Bioactive Peptides from Monkfish (Lophius litulon) Swim Bladders: Production, Identification, Antioxidant Activity, and Stability.

In the study, papain was chosen from five proteases to hydrolyze proteins of monkfish swim bladders for effectively utilizing monkfish (Lophius litulon) processing byproducts, and the hydrolysis conditions of papain were optimized as hydrolysis temperature of 65 °C, pH 7.5, enzyme dose 2.5% and time 5 h using single-factor and orthogonal experiments. Eighteen peptides were purified from the swim bladder hydrolysate of monkfish by ultrafiltration and gel permeation chromatography methods and identified as YDYD, QDYD, AGPAS, GPGPHGPSGP, GPK, HRE, GRW, ARW, GPTE, DDGGK, IGPAS, AKPAT, YPAGP, DPT, FPGPT, GPGPT, GPT and DPAGP, respectively. Among eighteen peptides, GRW and ARW showed significant DPPH· scavenging activities with EC50 values of 1.053 ± 0.003 and 0.773 ± 0.003 mg/mL, respectively; YDYD, QDYD, GRW, ARW and YPAGP revealed significantly HO· scavenging activities with EC50 values of 0.150 ± 0.060, 0.177 ± 0.035, 0.201 ± 0.013, 0.183 ± 0.0016 and 0.190 ± 0.010 mg/mL, respectively; YDYD, QDYD, ARW, DDGGK and YPAGP have significantly O2-· scavenging capability with EC50 values of 0.126 ± 0.0005, 0.112 ± 0.0028, 0.127 ± 0.0002, 0.128 ± 0.0018 and 0.107 ± 0.0002 mg/mL, respectively; and YDYD, QDYD and YPAGP showed strong ABTS+· scavenging ability with EC50 values of 3.197 ± 0.036, 2.337 ± 0.016 and 3.839 ± 0.102 mg/mL, respectively. YDYD, ARW and DDGGK displayed the remarkable ability of lipid peroxidation inhibition and Ferric-reducing antioxidant properties. Moreover, YDYD and ARW can protect Plasmid DNA and HepG2 cells against H2O2-induced oxidative stress. Furthermore, eighteen isolated peptides had high stability under temperatures ranging from 25-100 °C; YDYD, QDYD, GRW and ARW were more sensitive to alkali treatment, but DDGGK and YPAGP were more sensitive to acid treatment; and YDYD showed strong stability treated with simulated GI digestion. Therefore, the prepared antioxidant peptides, especially YDYD, QDYD, GRW, ARW, DDGGK and YPAGP from monkfish swim bladders could serve as functional components applied in health-promoting products because of their high-antioxidant functions.

Effective Fermentation of Sugarcane Bagasse Whole Slurries Using Robust Xylose-Capable Saccharomyces cerevisiae

The pre-treatment of lignocellulose material towards cellulosic bioethanol production releases microbial inhibitors that severely limit the fermentation ability of Saccharomyces cerevisiae. This study evaluated to what degree robust xylose-capable strains may improve the fermentability of non-detoxified sugarcane bagasse (SCB) slurries derived from steam explosion (StEX) and further compared this to slurries derived from ammonia fibre expansion (AFEX) pre-treatment. Initial screening in separate hydrolyses and co-fermentation processes using StEx-SCB hydrolysates identified S. cerevisiae TP-1 and CelluXTM4 with higher xylose consumption (≥ 88%) and ethanol concentrations (≥ 50 g/L), and ethanol metabolic yields (≥89% relative to theoretical maximum), even in the presence of approximately 8 g/L of acetic acid. Under industrially relevant pre-hydrolysis simultaneous saccharification and co-fermentation (PSSCF) conditions of high solids loading (15%, w/w) and low enzyme dosage (8 mg protein per gram untreated biomass), the fermentation of StEx-treated SCB whole slurry achieved ethanol yields of 208 and 224 L per Mg raw dry SCB using S. cerevisiae TP-1 and CelluXTM4, respectively. Under the same solids loading and enzyme dosages, the PSSCF of ammonia fibre expansion (AFEXTM) pre-treated SCB achieved ethanol yields of 234 and 251 L per Mg raw dry SCB using TP-1 and CelluXTM4, respectively. The study achieved non-detoxified whole-slurry co-fermentation using StEx pre-treated SCB, with higher ethanol yields than previously reported, by utilising robust xylose-capable strains. The results of this work provide insights into the potential use of inhibitor-tolerant S. cerevisiae strains TP-1 and CelluXTM4 as ethanologens for the fermentation of steam-exploded and undetoxified SCB whole slurries.

ENZYMATIC UPCYCLING OF BACTERIAL CELLULOSE FROM KOMBUCHA TO OBTAIN CELLOBIOSE

"The production of kombucha generates bacterial cellulose (BC) as a by-product, which is usually discarded. However, BC can be a source of cellobiose, a disaccharide with prebiotic benefits. In this study, the yield of cellobiose released from BC collected from a medium-sized kombucha producer was evaluated by enzymatic hydrolysis using the commercial cocktail Celluclast 1.5 L. The BC was hydrolyzed at solid contents of 2, 3 and 4% (m/v), enzyme dosage of 2.2 U/g cellulose, pH 5, 50 °C, and 150 rpm for 72 h. Industrial BC was characterized by FTIR and XRD to confirm the presence of common BC characteristics. The same analyses were performed after enzymatic hydrolysis, resulting in a change in crystallinity. The maximum cellobiose production (10-11 g/L) was obtained with 4% BC (w/v) in 48 h of hydrolysis; there was no significant difference when the time was extended to 72 h. The maximum glucose production under the same conditions was 3 g/L, showing that Celluclast 1.5 L has high cellobiose selectivity (78%). However, the cellobiose yield only ranged from 35 to 26%, indicating that cellobiose accumulation in the medium caused enzyme inhibition."

Effects of Rooibos (Aspalathus linearis) on the Testicular Parenchyma of Adult BALB/C Mice Submitted to a Hypercaloric Diet

Oxidative stress due to obesity plays a detrimental role in the testicular microenvironment and sperm parameters. We explored the impact of a hypercaloric diet in male BALB/c mice as a condition to trigger damage to the spermatogenic process and the antioxidant effect of Aspalathus linearis as well. We used a hypercaloric diet in animals divided into 3 groups: Control, Hypercaloric diet control (HC) and Hypercaloric diet and Rooibos infusion (HCR). Morphometric parameters, enzyme dosages, cell viability, and tubular histopathology were evaluated. Body weight increased in HCR animals at weeks 3, 4, and 8. We found a reduction in seminiferous epithelium height, with an increase in the tubular diameter of the HCR group. Catalase levels were lower in HC and HCR, while carbonyl protein was decreased in HC. We estimate that it induces oxidative stress (OS) capable of affecting the seminiferous epithelium and that the infusion of A. linearis does not demonstrate a potential benefit in cell preservation.