Acid Hydrolysis Research Articles

PH-responsive release of ciprofloxacin hydrochloride from micro-, nano-, and functionalized nanocellulose

This research evaluated pH-responsive release characteristics for the drug (ciprofloxacin hydrochloride) from micro-, nano-, and functionalized cellulose forms. Nanocrystalline cellulose (NCC) was prepared from microcrystalline cellulose (MCC) by sulfuric acid hydrolysis. The aldehyde (–CHO) groups were introduced at the carbon-2 (C-2) and carbon-3 (C-3) positions of glucose moiety of the cellulose network by selective oxidation to form di-aldehyde nanocellulose (DANC). The conversion was validated by chemical, spectroscopic, morphological, and crystallographic analysis. Drug binding capacity (mg/g) of DANC was higher (200.8 mg/g) compared to NCC (138.3 mg/g) and MCC (120.2 mg/g), respectively. The increase in pH from 2.5 to 8.5 enhanced drug release for all the excipients. At pH 2.5, slow release of the drugs was observed. In 6 h, DANC released 44.7 % of the loaded drug at pH 2.5. However, drug release reached equilibrium (84.8 % of loaded drug) within 10 min at pH 8.5. The release kinetics at acidic pH were validated using zero-order, first-order, Higuchi, and Korsmeyer-Peppas kinetics models. Higuchi and Korsmeyer–Peppas' kinetic models interpreted drug release phenomena with a good fit. This implies that diffusion, dissolution, swelling, and slight erosion contribute to drug release. The results suggest that selective functionalization can be applied to cellulose for its potential applications in pH-responsive drug delivery, and therefore, the functionalized cellulose deserves immediate attention.

Sustainable energy enhancement strategy from Chlorella vulgaris microalgae biomass resource

ABSTRACT Growing demand for renewable and sustainable energy sources has prompted research into bioethanol production as a viable alternative to hydrocarbon fuel for automobile engines. Based on their high carbohydrate content, Chlorella vulgaris microalgae were chosen for this study as a feasible biomass for bioethanol synthesis. After conducting microwave-based acid hydrolysis with varying acid concentrations of sulfuric acid (H2SO4) for 1–15 min, this study found that 3% H2SO4 for 5 min yielded the highest yield of reducing sugar (6.77 g/L). In this work, the RSM approach of central composite design (CCD) was utilized for modeling and optimization of ethanol fermentation and the MATLAB Simulink approach was employed for the simulation of ethanol fermentation. This study compared the effects of using Saccharomyces cerevisiae yeast for fermentation at different fermentation times (12 to 48 h), temperatures (28 to 32°C), and size of inoculum (0.5–1.5 g/L). Based on the actual and predicted results, the best conditions for fermentation were 36 h of time, 30°C of temperature, and 1.5 g/L of inoculum size. This gave the maximum ethanol concentration of 3.31 g/L. Furthermore, the RSM method provides minimum error and maximum R2 value results for ethanol production compared to MATLAB simulation prediction (MSP). In addition, residue biomass from biofuel production is evaluated for its suitability for a further form of biofuel production. This research explores the opportunities for zero-waste biomass utilization in the development of biofuels.

Bioethanol production from dilute acid hydrolysis of cassava peels, sugar beet pulp, and green macroalgae (Ulva lactuca)

This study presents the characterization and application of different pretreatment possibilities to optimize simple carbohydrate production from representative feedstock, followed by ethanol production through optimized saccharification steps using suitable microorganisms. Total soluble carbohydrates and carbohydrate yield were evaluated using dilute acid hydrolysis of biomass and reference materials (starch and cellulose) under different conditions. To explore two-factor interactions, the Plackett-Burman design of experiments was used in the statistical screening of variables and then transformed to a full-factorial design based on the significant variables. According to the experimental findings, dilute acid hydrolysis can yield a considerable amount of soluble carbohydrates. The goodness of fit of the model was evaluated using the coefficient of determination. The optimized carbohydrate yields of the biomass were 0.76 g/g cassava peels, 0.35 g/g sugar beet pulp, and 0.36 g/g green macroalgae. Bioethanol production from optimized hydrolysis conditions using Saccharomyces cerevisiae and Scheffersomyces stipitis DSM 3651, led to a maximum ethanol yield of 0.286 g/g from cassava peels and 0.033 g/g from sugar beet pulp, while using Neurospora intermedia DSM 1265 led to a maximum ethanol yield of 0.076 g/g from green macroalgae. Hence, these biomasses are considered valuable feedstock for bioethanol production with cassava peels having the highest potential.

Unveiling the Cleavage Mechanism of an RNA Model Compound on the whole pH Scale: Computations Meet Experiments in the Determination of Reaction Rates.

The knowledge of the mechanism of reactions occurring in solution is a primary research line both in the context of theoretical-computational chemistry and in the field of organic and bio-organic chemistry. Given the importance of the hydrolysis of nucleic acids in life-related phenomena, here we present a combined experimental and computational study on the cleavage of an RNA model compound. This phosphodiester features a cleavage rate strictly dependent on the pH with three different dependence domains. Such experimental evidence, highlighted by an in-depth kinetic investigation, unequivocally suggests a change in the reaction mechanism along the pH scale. In order to interpret the data and to explain the experimental behavior, we have applied a theoretical-computational procedure, involving a hybrid quantum/classical approach, able to model chemical reactions in complex environments, i.e. in solution. This study turns out to quantitatively reproduce the experimental data with accuracy and, in addition, provides useful mechanistic insight into the transesterification process of the investigated compound. The study indicates that the cleavage can occur through an ANDN, an AN+DN, and a DNANmechanism depending on the pH values.

ОПРЕДЕЛЕНИЕ РАЦИОНАЛЬНЫХ РЕЖИМНЫХ ПАРАМЕТРОВ ФЕРМЕНТАЦИИ БИОВОДОРОДА С ИСПОЛЬЗОВАНИЕМ CLOSTRIDIUM BUTYRICUM И ENTEROBACTER CLOACAE НА ГИДРОЛИЗАТАХ СОЛОМЫ, АКТИВИРОВАННОЙ ПАРОВЗРЫВНОЙ ОБРАБОТКОЙ

Studies have been conducted to determine the possibility of using agricultural waste, in particular straw, for the production of biohydrogen. In our work, we used two types of straw hydrolysates (after acidic and enzymatic hydrolysis), pre-activated by steam blasting at steam temperatures of 100, 165, 210 0C. The hydrolysates were diluted with distilled water to a concentration of reducing agents (RR) equal to 1.0, 1.5 and 2.0% of their mass in order to determine the rational concentration. Two cultures of anaerobic microorganisms were tested on 18 samples of hydrolysates: a strain of bacteria of the genus Clostridium Butyricum E.VI .3.2.1 (no. VKPM B-9619), a strain of bacteria of the genus Enterobacter cloacae (no. VKPM B-1980). The fermentation temperature for all samples was set at 37 ± 0.5 0C, pH 5.5 ± 0.1. The released gas accumulated in the gas tank; its samples were taken every 12 hours and analyzed for the volume content of hydrogen. After establishing the rational initial concentration of the substrate, the temperature of steam explosive activation of straw, the type of hydrolysate and the maximum yield of biohydrogen, the cultivation temperature and pH for each culture were further changed in order to determine the rational parameters: for Clostridium Butyricum, the cultivation temperature was set to 32 ±0.5, 37 ±0.5 and 42±0.5 0C for Enterobacter cloacae – 36±0.5, 37±0.5, 38±0.5 0C; the pH for all samples was set in the range of 5...6 in increments of 0.5 ± 0.1). On acidic straw hydrolysates, Clostridium Butyricum demonstrated the best productivity (steam explosion temperature 165 0C) - hydrogen yield was 73 ml/g, on hydrolysates fermented by Enterobacter cloacae (steam explosion temperature 210 0C), hydrogen yield was 50 ml/g. Both cultures are capable of producing the maximum amount of hydrogen at a concentration of reducing substances of 2%. The rational fermentation temperature for Clostridium Butyricum is 37 ± 0.5 0C, for Enterobacter cloacae – 36 ± 0.50 C, for both cultures – pH = 6.

Extraction and preparation of cellulose nanocrystal from Brewer's spent grain and application in pickering emulsions

In recent years, the search for novel Pickering stabilizers has attracted much interest in the food, cosmetic and pharmaceutical industries. In this work, brewer's spent grain cellulose (BSGC) was successfully extracted by diluted acid, alkaline and bleaching treatments, and then brewer's spent grain cellulose nanocrystal (BSGCNC) were obtained by acid hydrolysis treatment of BSGC. The properties of the BSGCNC were characterized, and the results showed that the BSGCNC had a rod-like structure with high crystallinity (67.09%). Then the emulsification properties of BSGCNC were evaluated by different concentrations and water-oil ratios, and the results showed that BSGCNC were able to form stable Pickering emulsions. This study suggested that cellulose nanocrystal (CNC) could be extracted from brewer's spent grain which was used as food waste, as a stabilizer for Pickering emulsions.

Chitin quantitation (as glucosamine) in food raw materials by spectrophotometry

Chitin is a water insoluble nitrogen-containing polysaccharide made from N-acetyl-D-glucosamine containing β-(1→4)-linkages. In food, chitin is considered as a source of fiber with prebiotic properties to gut microflora. Chitin content varies widely in nature from 1% (yeasts) up to 64% (butterfly cuticles) and is mostly found in filamentous or mushroom forming fungi, insects and crustaceans. This spectrophotometric method is suitable for chitin quantitation (reported as glucosamine) in food raw materials like insects (mealworm larvae, crickets), shrimps, mushrooms and fungi in a research (non-routine) laboratory. To remove interferences, the sample is defatted (Soxhlet) prior to acid hydrolysis in 6 M HCl. The color complex is developed after the addition of Katano's reagent (a mix of 0.05 mol/L sodium metasilicate, 0.6 mol/L sodium molybdate, 30% dimethyl sulfoxide and 1.42 mol/L acetic acid) at 70 °C for 30 min and measured at 750 nm against blank. A five-point linear calibration (5–100 µg/mL) is used. Limit of detection is 3 µg GLCN/mL. The correlation (R2) with an HPLC method for chitin analysis is at least 0.93.•a reliable alternative to an HPLC method•does not require expensive equipment•deproteination by alkali is not necessary for most matrices - saves about 30% of time

Isolation of Cellulose Nanosphere from Corn Husk as a Filler for UV-Cured PEGDMA Nanocomposite Hydrogels

Cellulose nanosphere (CNS) was isolated from corn husk by delignification, bleaching, acid hydrolysis, dialysis, and sonication. Successful isolation of CNS was confirmed by FTIR Analysis. The isolated CNS was found to have an average diameter of 18 nm and crystallinity index of 70% using TEM and XRD Analysis, respectively. A decrease in onset degradation temperature (Tonset) and an increase in residual mass were also observed in the TG analysis of cellulose fiber and CNS. Nanocomposite hydrogels using poly (ethylene glycol) dimethacrylate (PEGDMA) as matrix and CNS as nanofiller was prepared by UV-curing. FTIR Analysis revealed similar transmittance patterns among all the treatments. Thermal characterization showed that the addition of CNS lowers the Tonset and Tmax while increasing the temperature required for the total degradation of the UV-cured nanocomposite hydrogels.

Developing biobased and degradable polyazomethines from hemin

The development of biobased polymers is emerging as a critical issue for researchers in this era, especially for conjugated or semiconducting polymers, due to the lack of natural conjugated building blocks. In addition, it is of urgent importance to develop degradable polymers to diminish the increasing amount of plastic waste. Therefore, we aim to utilize hemin-based materials as a building block to develop semi-conjugated, degradable, and biobased polymers in this study. Accordingly, hemin derived from bovine is modified to remove the ferric ion and functionalize with amine or aldehyde groups. The aldehyde-functionalized protoporphyrin is copolymerized with p-phenylenediamine, 2,7-fluorenediamine, and amine-functionalized protoporphyrin to form a series of polyazomethines of PDA, FDA, and PPIX. The semi-conjugated polyazomethines exhibit varied electrostatic potential distributions and frontier energy levels based on their compositions; in addition, all the polyazomethines present high biobased contents spanning the range of 60–80%. Notably, PPIX can be rapidly depolymerized by acid hydrolysis with 0.01 mol L−1 of HCl within several hours, guaranteed by the evolutions of optical absorption and size-exclusion chromatography, which show that the polyazomethines degrade to monomers to short-chain oligomers. In the aspect of the optoelectronic device application, the semi-conjugated characteristics of the hemin-based polyazomethines give rise to their high performance as a photoresponsive polymer electret in photonic transistor memory. By fine-tuning the molecular structure and energy levels, the developed polyazomethine of FDA achieves decent data discernibility and long-termed cyclic operation as a component of memory electronics, thereby rendering green electronics exceptionally economical and environmentally feasible.

Characterization and safety assessment of bamboo shoot shell cellulose nanofiber: Prepared by acidolysis combined with dynamic high-pressure microfluidization

The preparation of cellulose nanofiber (CNF) using traditional methods is currently facing challenges due to concerns regarding environmental pollution and safety. Herein, a novel CNF was obtained from bamboo shoot shell (BSS) by low-concentration acid and dynamic high-pressure microfluidization (DHPM) treatment. The resulting CNF was then characterized, followed by in vitro and in vivo safety assessments. Compared to insoluble dietary fiber (IDF), the diameters of HIDF (IDF after low-concentration acid hydrolysis) and CNF were significantly decreased to 167.13 nm and 70.97 nm, respectively. Meanwhile, HIDF and CNF showed a higher crystallinity index (71.32 % and 74.35 %). Structural analysis results indicated the successful removal of lignin and hemicellulose of HIDF and CNF, with CNF demonstrating improved thermostability. In vitro, a high dose of CNF (1500 μg/mL) did not show any signs of cytotoxicity on Caco-2 cells. In vivo, no death was observed in the experimental mice, and there was no significant difference between CNF (1000 mg/kg·bw) and control group in hematological index and histopathological analysis. Overall, this study presents an environmentally friendly method for preparing CNF from BSS while providing evidence regarding its safety through in vitro and in vivo assessments, laying the foundation for its potential application in food.

Recovery of sulfuric acid during sugar purification from pretreated wheat straw hydrolysate using electro-electrodialysis system for 2G bioethanol production

Concentrated acid hydrolysis (CAH) of lignocellulosic biomass (LCB) is an established method to obtain a near theoretical yield of monomeric sugars from the biomass. The CAH process produced 83.23 % of glucose from pretreated wheat straw (PWS) at optimum conditions (i.e., stage I = 74 % w/w acid, 1:2 biomass loading, and 50 °C for 1 h; and stage II = 30 % w/w acid, 90 °C for 2 h). However, the separation of sugar from acidic hydrolysate is a major constraint of this technology. In this study, an electro-electrodialysis (EED) process using a novel anion exchange membrane (AEM) has been developed to recover sulfuric acid from biomass hydrolysate. The synthetic hydrolysate (i.e., feed acid concentration = 2 M; glucose = 80 g L−1) was used to optimize the EED process parameters. The acid was successfully recovered from alkali pretreated wheat straw (PWS) hydrolysate using the most effective EED process parameters. This resulted in an 82.72 % acid recovery in the permeate under the following conditions: current density of 88 mA cm−2, flow rate of 3 L h−1, and feed acid content of 2 M. During the EED process, the highest glucose recovery in the feed was 90.98 %, achieved with a maximum current efficiency of 93.57 % and the lowest energy consumption of 0.052 kW h mol−1 at optimal conditions using PWS Hydrolysate. Saccharomyces cerevisiae fermented the acid-free PWS hydrolysate, resulting in a maximum ethanol yield of 92.3 %. The EED process cost of $0.049 kg H2SO4−1 and total revenue was $0.02 kg biomass−1 from the second batch onwards suggest the feasibility of the EED process for large-scale 2G bioethanol productions.

Process-structure-property relationships of cellulose nanocrystals derived from Juncus effusus stems on ҡ-carrageenan-based bio-nanocomposite films

This study investigates the potential of Juncus plant fibers as a renewable source for producing cellulose nanocrystals (CNs) to reinforce polymers. Cellulose microfibers (CMFs) were extracted with a 0.43 ± 0.2 μm diameter and 69 % crystallinity through alkaline and bleaching treatments, then subjected to sulfuric acid hydrolysis, yielding four CN types (CN10, CN15, CN20 and CN30) with distinct physico-chemical properties and aspect ratios (47, 55, 57, and 60). The study assessed the influence of cellulose nanocrystals (CNs), incorporated at different weight percentages (3 %, 5 %, and 8 %), on thermal, transparency, and mechanical properties in k-carrageenan (CA) biocomposite films. The results indicate significant enhancements in these characteristics, highlighting good compatibility between CNs and CA matrix. Particularly noteworthy is the observed substantial improvement in tensile strength at an 8 wt% loading, with values of 23.43 ± 0.83 MPa for neat CA, 33.53 ± 0.83 MPa for CA-CN10, 36.67 ± 0.71 MPa for CA-CN15, 37.65 ± 0.56 MPa for CA-CN20, and 39.89 ± 0.77 MPa for CA-CN30 composites. Furthermore, the research explores the connection between the duration of hydrolysis and the properties of cellulose nanocrystals (CNs), unveiling their influence on the characteristics of nanocomposite films. Prolonged hydrolysis enhances CN crystallinity (CrI), aspect ratio, and surface charge content, consequently enhancing mechanical features like strength and flexibility in these films. These findings demonstrate the potential of Juncus plant fibers as a natural and eco-friendly resource for producing CNs that effectively reinforce polymers, making them an attractive option for diverse applications in the field.

Development of an Integrated Bioprocess System for Bioethanol and Arabitol Production from Sugar Beet Cossettes.

An innovative integrated bioprocess system for bioethanol production from raw sugar beet cossettes (SBC) and arabitol from remaining exhausted sugar beet cossettes (ESBC) was studied. This integrated three-stage bioprocess system is an example of the biorefinery concept to maximise the use of raw SBC for the production of high value-added products such as sugar alcohols and bioethanol. The first stage of the integrated bioprocess system was simultaneous sugar extraction from SBC and its alcoholic fermentation to produce bioethanol in an integrated bioreactor system (vertical column bioreactor and stirred tank bioreactor) containing a high-density suspension of yeast Saccharomyces cerevisiae (30 g/L). The second stage was the pretreatment of ESBC with dilute sulfuric acid to release fermentable sugars. The resulting liquid hydrolysate of ESBC was used in the third stage as a nutrient medium for arabitol production by non-Saccharomyces yeasts (Spathaspora passalidarum CBS 10155 and Spathaspora arborariae CBS 11463). The obtained results show that the efficiency of bioethanol production increased with increasing temperature and prolonged residence time in the integrated bioreactor system. The maximum bioethanol production efficiency (87.22 %) was observed at a time of 60 min and a temperature of 36 °C. Further increase in residence time (above 60 min) did not result in the significant increase of bioethanol production efficiency. Weak acid hydrolysis was used for ESBC pretreatment and the highest sugar yield was reached at 200 °C and residence time of 1 min. The inhibitors of the weak acid pretreatment were produced below bioprocess inhibition threshold. The use of the obtained liqiud phase of ESBC hydrolysate for the production of arabitol in the stirred tank bioreactor under constant aeration clearly showed that S. passalidarum CBS 10155 with 8.48 g/L of arabitol (YP/S=0.603 g/g and bioprocess productivity of 0.176 g/(L.h)) is a better arabitol producer than Spathaspora arborariae CBS 10155. An innovative integrated bioprocess system for the production of bioethanol and arabitol was developed based on the biorefinery concept. This three-stage bioprocess system shows great potential for maximum use of SBC as a feedstock for bioethanol and arabitol production and it could be an example of a sustainable 'zero waste' production system.

LC-HRMS and NMR studies for the characterization of degradation impurities of ubrogepant along with the in silico approaches for the prediction of degradation and toxicity

Ubrogepant is the first oral calcitonin gene-related peptide (CGRP) receptor antagonist which is used for the acute treatment of migraine in adults. The present study employs liquid chromatography-high resolution mass spectrometry (LC-HRMS) and nuclear magnetic resonance spectroscopy (NMR) techniques for the identification and characterization of degradation impurities of ubrogepant. The forced degradation study of ubrogepant was performed as per the International Council for Harmonisation (ICH) Q1A and Q1B guidelines. The in silico degradation profile of ubrogepant was predicted by Zeneth. It was observed that ubrogepant was labile to acidic hydrolysis, basic hydrolysis, and oxidative degradation conditions (H2O2), although it was stable in neutral hydrolysis and photolytic (UV light and visible light) conditions. Eight degradation impurities were formed, which were separated on reversed-phase HPLC with a gradient program on an InertSustain C8 column (4.6 × 250 mm, 5 µm) using 10 mM ammonium formate (pH unadjusted) and acetonitrile as the mobile phase. The structures of all the degradation impurities were characterized using the exact masses obtained from the HRMS/MS. Further, NMR studies were conducted on two major degradation impurities (UB-4 and UB-7). A plausible mechanism was proposed to support the structures of all the degradation impurities of UBR. In silico toxicity and mutagenicity assessment were done by DEREK Nexus, SARAH Nexus, and ProTox-II.

Conditions and Mechanism of Formation of the Maillard Reaction Pigment, Furpenthiazinate, in a Model System and in Some Acid Hydrolyzates of Foods and its Biological Properties.

Furpenthiazinate is a yellow pigment formed by the Maillard reaction between cysteine and furfural under strongly acidic conditions. Here, we describe the conditions and mechanism of pigment formation in a model system and in an acid hydrolyzate of food and analyze its biological properties. A reaction solution containing 32 mM cysteine and 128 mM furfural or 64 mM cysteine and 256 mM furfural in the presence of 2-6 M hydrochloric acid that was heated to 110 °C for 1-2 h yielded approximately 3 mM furpenthiazinate. Nuclear magnetic resonance analysis of furpenthiazinate prepared using 1-13C or 5-13C d-ribose suggests that it was formed through the condensation of cysteine and two C5 chains derived from pentose with the dehydration and elimination of formic acid. Furpenthiazinate was detected in mieki, a seasoning, and some acid hydrolyzates of food, and it did not show antibacterial or mutagenic activity.

Monosaccharide composition of lignocellulosic matrix—Optimization of microwave-assisted acid hydrolysis condition

Compositional analysis of polysaccharides is crucial in many applications of analytical chemistry, and typically involves hydrolysis as initial step, to break glycosidic bonds and release individual monosaccharide units. We developed a new method for the microwave-assisted acid hydrolysis of polysaccharides, here applied for determining the composition of the polysaccharide fraction within the lignocellulosic matrix of Pinus sylvestris. The optimisation of reaction conditions was carried out using a GC–MS method after a double-step sugar derivatization process.Under the optimized conditions, specifically, employing 2 M TFA, 40 min, and 120 °C, a high depolymerisation yield was achieved with minimal degradation. Furthermore, the amount of polysaccharides detected in pine wood aligns with the results in existing literature, substantiating the determined chemical composition.The synergy of microwave-assisted acid hydrolysis and full factorial design not only facilitated the determination of the optimal hydrolysis conditions but also enabled the assessment of the parameters influencing the polysaccharide hydrolysis process and their relationships. This approach made it feasible to achieve maximum hydrolysis efficiency while minimizing analyte degradation, employing a method that reduces environmental impact through the use of microwave energy. This strategy effectively reduced the required reaction temperature, time, and reagent quantities.

Nanocrystalline cellulose from Arctic brown algae Laminaria digitata and Saccharina latissima

Nanocrystalline cellulose (NCC) was successfully obtained from two Arctic brown algae species, Laminaria digitata and Saccharina latissima. The production process involved a sequential extraction of non-cellulosic compounds, an environmentally friendly bleaching process with hydrogen peroxide, and subsequent acidic hydrolysis, resulting in the formation of nanosized rod-like particles. Comprehensive assessments were conducted to evaluate the influence of hydrolysis conditions, specifically using hydrochloric and sulfuric acids, on the key characteristics of the nanocellulose. The resulting NCC was characterized using various techniques including Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA, DTG), scanning electron microscopy (SEM), laser diffraction, and low-temperature nitrogen sorption. The obtained algal NCC demonstrated a yield of 76–91%, a degree of polymerization of 150–230 units, and a crystallinity index of 69–80%. The choice of acid during the production significantly influenced the thermal stability, particle size distribution, and porous properties of the samples. Remarkably, the algal NCC, acquired in the form of stable gel-like suspensions, exhibited robust stability during extended storage. These materials showcase promising potential for applications in biomedicine, serving as versatile components for hydro/aerogels, matrices, and fillers in the development of advanced medical dressings.

Characterisation of a capsular polysaccharide from Moraxella nonliquefaciens CCUG 348T

Moraxella nonliquefaciens is a commensal of the human upper respiratory tract (URT) but on rare occasions is recovered in cases of ocular, septic and pulmonary infections. Hence there is interest in the pathogenic determinants of M. nonliquefaciens, of which outer membrane (OM) structures such as fimbriae and two capsular polysaccharide (CPS) structures, →3)-β-D-GalpNAc-(1→5)-β-Kdop-(2→ and →8)-α-NeuAc-(2→, have been reported in the literature. To further characterise its surface virulence factors, we isolated a novel CPS from M. nonliquefaciens type strain CCUG 348T. This structure was elucidated using NMR data obtained from CPS samples that were subjected to various degrees of mild acid hydrolysis. Together with GLC-MS data, the structure was resolved as a linear polymer composed of two GalfNAc residues consecutively added to Kdo, →3)-β-D-GalfNAc-(1→3)-α-D-GalfNAc-(1→5)-α-(8-OAc)Kdop-(2→.Supporting evidence for this material being CPS was drawn from the proposed CPS biosynthetic locus which encoded a potential GalfNAc transferase, a UDP-GalpNAc mutase for UDP-GalfNAc production and a putative CPS polymerase with predicted GalfNAc and Kdo transferase domains. This study describes a unique CPS composition reported in Moraxella spp. and offers genetic insights into the synthesis and expression of GalfNAc residues, which are rare in bacterial OM glycans.

Optimizing healthy snacks for diabetics: Study of fiber and starch digestibility of glucomannan-modified Growol cookies

Diabetes mellitus (DM) is an emergency health problem in the 21st century. High dietary fiber and resistant starch foods with low starch digestibility are solutions for DM. The addition of glucomannan to food can optimize the levels of dietary fiber, resistant starch, and starch digestibility. This study aimed to examine the optimization of dietary fiber, resistant starch, and starch digestibility in Growol cookies supplemented with glucomannan. Laboratory observations were conducted at the Universitas Respati Yogyakarta and Chemmix Pratama Yogyakarta Laboratory between July and September 2023. Cookies consisted of cookies A (negative control), B (positive control), C (modified 10-gram inulin), D (modified glucomannan 3%), and E (modified glucomannan 7%). Dietary fiber and resistant starch analyses were performed using the multi-enzyme method. Starch digestibility was determined by comparing the starch content obtained using the enzymatic method with that obtained using the acid hydrolysis method. Statistical analyses were performed using ANOVA and Kruskal-Wallis tests. There were differences in dietary fiber and resistant starch among the variants (p<0,001) with the highest being cookies E. There was no difference in starch digestibility between the variants (p=0,104) with the lowest being cookies E. In conclusion, glucomannan addition can optimize dietary fiber and resistant starch levels, as well as the starch digestibility of Growol cookies as a healthy snack for diabetics.

Developing a novel, low-cost, antimicrobial, and biodegradable pectin/HEC/ZnO biofilm for edible food packaging applications

AbstractThe purpose of this study was to investigate the potential of pectin extracted from orange waste by acid hydrolysis and prepared Pectin/ hydroxyethyl cellulose (HEC)/ZnO nanoparticles (ZnO-NPs) biofilm for food packaging applications. The pectin/HEC/ZnO biofilms were prepared in an aqueous solution at room temperature using solvent casting method and characterized by different techniques such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), and scanning electron microscope (SEM). Also, thermal gravimetric analysis (TGA), mechanical properties, and water vapor permeability-WVP were evaluated. Moreover, its antimicrobial activity against Gram negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Salmonella enterica Typhimiurium) and two Gram positive bacteria (Listeria monocytogenes and Staphylococcus aureus), and also has antifungal activity against Candida albicans was assessed. The obtained results display that the water vapor permeability (WVP) indicated a reduction in permeability with increased ZnO concentration, with WVPs ranging from 2.55 × 10−12 to 4.28 × 10−12 gm/pas.m2, which indicates that our pectin/HEC/ZnO bionanocomposite biofilm could efficiently decrease moisture transfer, thereby potentially extending the shelf-life of packaged food products. Furthermore, the results showed enhanced tensile strength and flexibility in the biofilms with the addition of 1% ZnO nanoparticles from 1.2 to 2.6 MPa and 4.5 to 13 MPa respectively. The WVP indicated a reduction in permeability with increased ZnO concentration, with WVPs ranging from 2.55 × 10−12 to 4.28 × 10−12 gm/pas.m2. The antimicrobial activity against pathogens such as Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica Typhimurium, Listeria monocytogenes, Staphylococcus aureus, and Candida albicans was significant, with a 99.96% reduction in E. coli counts at a biofilm concentration of 200 mg/mL. Furthermore, the current study revealed that the synthesized bionanocomposite biofilms had excellent qualities such as transparency, flexibility, low cost, and being environmentally friendly. The pectin/HEC/ZnO bionanocomposite was found to be an ideal biofilm for food packaging due to its safety and affordability, which is able to prolong food shelf-life.