Acid Hydrolysis Research Articles

Morphology, Crystallinity and Thermal Properties of Nanocrystalline Cellulose Isolated of Sisal Fiber by Acid Hydrolysis-Ultrasonication

Nanocrystalline cellulose (NCC) from natural Agave sisalana (Sisal) fibers were isolated using a combination of chemical and mechanical processes. The chemical treatment begins with soaking the fiber in a sodium hydroxide (NaOH) solution with a concentration of 5 wt.% at a temperature of 90°C for 60 minutes. Then following by bleaching (fiber refining) using a hydrogen peroxide solution (H2O2) with a concentration of 3 wt.% (weight), at a temperature of 60°C, and pH of 10 for 30 minutes. It aims to eliminate the presence of hemicellulose and lignin contained in the fiber. Fibrillation Micro into nano Sisal fibers using sulfuric acid (hydrolysis process). Sulfuric acid (H2SO4) with 55 wt.% at temperature 60°C for 30 minutes produced NCC with a diameter of 5±1 nm (D) and a length of 260±10 nm (L), as seen using a TEM (transmission electron microscope). The web-like network structured shape of NCC results in a high aspect ratio (L/D) value is 52. The acid hydrolysis-ultrasonication process produced a high crystallinity index of 78.82% through the XRD (x-ray diffraction) test. The crystallinity and aspect ratio of NCC show that Sisal fiber is a suitable material as a filler for bio-nanocomposite materials. The maximum temperature (Tmax) of NCC decreased by 10°C due to sulfate ions attached to the cellulose structure, causing the thermal stability to drop from 348°C to 338°C.

Fast and Accurate Disulfide Bridge Detection

Recombinant expression of proteins, propelled by therapeutic antibodies, has evolved into a multibillion dollar industry. Essential here is the quality control assessment of critical attributes, such as sequence fidelity, proper folding, and posttranslational modifications. Errors can lead to diminished bioactivity and, in the context of therapeutic proteins, an elevated risk for immunogenicity. Over the years, many techniques were developed and applied to validate proteins in a standardized and high-throughput fashion. One parameter has, however, so far been challenging to assess. Disulfide bridges, covalent bonds linking two cysteine residues, assist in the correct folding and stability of proteins and thus have a major influence on their efficacy. Mass spectrometry promises to be an optimal technique to uncover them in a fast and accurate fashion. In this work, we present a unique combination of sample preparation, data acquisition, and analysis facilitating the rapid and accurate assessment of disulfide bridges in purified proteins. Through microwave-assisted acid hydrolysis, the proteins are digested rapidly and artifact-free into peptides, with a substantial degree of overlap over the sequence. The nonspecific nature of this procedure, however, introduces chemical background, which is efficiently removed by integrating ion mobility preceding the mass spectrometric measurement. The nonspecific nature of the digestion step additionally necessitates new developments in data analysis, for which we extended the XlinkX node in Proteome Discoverer to efficiently process the data and ensure correctness through effective false discovery rate correction. The entire workflow can be completed within 1 h, allowing for high-throughput, high-accuracy disulfide mapping.

Efficient Protection of Paper‐Based Cultural Relics via In Situ Synthesis of Carbon Dots/Layered Double Hydroxide

AbstractPaper‐based cultural relics are of great value and have been facing irreversible damage caused by multiple factors, among which acid hydrolysis and ultraviolet photodegradation are the main processes leading to paper deterioration. Paper protection highly relies on a limited range of materials with single functions, and the design of new materials that ensure long‐term safety and efficiency by simultaneously addressing the issues of acidification and UV degradation in paper is highly desired. In this study, the introduction of carbon dots (CDs)‐enhanced layered double hydroxides (LDH) 0D/2D nanohybrids (CDs/Mg‐Al LDH)  is proposed as novel dual‐functional materials for paper protection against UV degradation and acidification. Through a CDs‐assisted in situ growth strategy, CDs/Mg‐Al LDH with ultrathin thickness (≈9.1 nm) and CDs‐intercalated structure are achieved. The CDs/Mg‐Al LDH nanohybrids demonstrate high dispersibility, strong UV absorption, and remarkable photostability, resulting in protected‐paper with decelerated acidification, oxidation, and yellowing degradation processes under both accelerated UV‐aging and dry‐heat conditions. Additionally, the protected‐paper can emit uniform blue light under 365 nm UV excitation allows for easy identification of the distributed CDs/Mg‐Al LDH within the paper, marking a unique and practical feature. This research paces a new direction for the protection of paper‐based relics with emerging carbon dots‐based 0D/2D nanomaterials.

Removal of heavy metal ions from water using nanocellulose-based membranes derived from macroalgae Chara corallina

Chara corallina is a freshwater macroalgae found in aquatic-terrestrial boundary environments. Their cellulose fibers have a crystallinity and biosynthesis similar to those of terrestrial plants. The algal nanocellulose (NC) was prepared through a series of chemical treatments, including alkaline, bleaching, grinding, and acid hydrolysis. The X-ray diffraction (XRD) crystallinity index of nanocellulose was 85.64%. The cellulose nanocrystals are seen in the form of nanorods, and the specific surface area of the sample of NC found was 5.823 m2g-1. The study aimed to test the effectiveness of a nanocellulose composite membrane in removing heavy metal ions, specifically cadmium (Cd), nickel (Ni), and lead (Pb) ions, from an aqueous solution. A vacuum filtration unit was used for the experiment, where up to five filter layers of composite membranes were examined for their ability to remove heavy metal ions. The results showed that the highest removal rates of Cd2+, Ni2+, and Pb2+ ions were 98.20%, 95.15%, and 93.80%, respectively, when using five layers of membranes of NC with the adsorbent dose set at 20 ppm. Cellulose and its derivatives are essential in sustainable technology for wastewater treatment, as they demonstrate exceptional performance in removing various types of pollutants, including heavy metals, dyes, and other pollutants. Cellulose is preferred due to its low cost, biodegradability, eco-friendliness, and simple surface modification.

Soluble Organic Compounds and Cyanide in Apollo 17 Lunar Samples: Origins and Curation Effects

AbstractWe analyzed 12 Apollo 17 samples through the Apollo Next Generation Sample Analysis (ANGSA) program to determine the abundances of a variety of compound classes, including amino acids, aldehydes, ketones, amines, carboxylic acids, and cyanide‐releasing species. Analyzed samples included portions of double drive tube 73001/73002, the bottom half of which (73001) was hermetically sealed under lunar vacuum, as well as lunar regolith samples from three different illumination environments that had been curated frozen for ∼50 years. Consistent with previous results, we detected low levels of amino acids in the hot‐water extracts of most samples (0.55–12.03 nmol/g in unhydrolyzed samples; 0.53–72.38 nmol/g after acid hydrolysis of the extracts). We also detected one‐carbon and two‐carbon species of amines, aldehydes, and carboxylic acids (i.e., methylamine, ethylamine, formaldehyde, acetaldehyde, formic acid, acetic acid) not previously reported in lunar samples, as well as insoluble cyanide‐forming species. Although these compounds are potential precursor molecules for amino acids, no specific precursor relationships could be determined. Nylon contamination was the likely source of some amino acids. Abundances of some species (e.g., cyanide) decreased with increasing depth in the drive tube, suggesting that exogenous delivery and concentration mechanisms near the surface outweighed surface degradation processes. In addition, we observed the potential cold trapping of volatile amines in the persistently shadowed samples analyzed. Finally, we noted the effects of different curation conditions; hermetic sealing appeared to preserve higher amounts of volatile compounds, while frozen curation did not have a noticeable preservation effect on the organic volatiles analyzed here.

Development of eco-friendly biofilms by utilizing microcrystalline cellulose extract from banana pseudo-stem

Banana pseudo-stem, often considered as an underutilized plant part was explored as a potential reinforced material to develop an eco-friendly biofilm for food packaging applications. In this study, Microcrystalline cellulose (MCC) was extracted from banana pseudo-stem by alkali and acid hydrolysis treatment. The extracted MCC was used as a reinforced material in different concentrated polyvinyl alcohol (PVA) matrix alone as well as both PVA and Carboxymethyl Cellulose (CMC) matrix to develop biofilm by solvent casting method. The synthesized MCC powder was characterized by scanning electron microscope to ensure its microcrystalline structure and to observe surface morphology. The biofilms composed of MCC, PVA, and CMC were assessed through Fourier-transform infrared spectroscopy (FTIR), mechanical properties, water content, solubility, swelling degree, moisture barrier property (Water Vapor Permeability - WVP), and light barrier property (Light Transmission and Transparency). The FTIR analysis showed the rich bonding between the materials of the biofilms. The film incorporating a combination of PVA, CMC, and MCC (S6) exhibited the highest tensile strength at 26.67 ± 0.152 MPa, making it particularly noteworthy for applications in food packaging. MCC incorporation increased the tensile strength. The WVP content of the films was observed low among the MCC-induced films which is parallel to other findings. The lowest WVP content was showed by 1% concentrated PVA with MCC (S4) (0.223 ± 0.020 10−9 g/Pahm). The WVP content of S6 film was also considerably low. MCC-incorporated films also acted as a good UV barrier. Transmittance of the MCC induced films at UV range were observed on average 38% (S2), 36% (S4) and 6% (S6) which were almost 6% lower than the control films. The S6 film demonstrated the lowest swelling capacity (1.42%) and water content, indicating a significantly low solubility of the film. The film formulated with mixing of PVA, CMC and MCC (S6) was ahead in terms of food packaging characteristics than other films. Also, the outcomes of this study point out that MCC can be a great natural resource for packaging applications and in that regard, banana pseudo-stem proves to be an excellent source for waste utilization.

Effect of polycarbodiimide, epoxy chain extenders and tannic acid on the hydrolysis and UV resistance of polylactic acid

Polylactic acid (PLA) possesses characteristics such as biodegradability, ease of processing, and environmental friendliness, making it an ideal alternative to petroleum-based polymers. However, PLA has drawbacks such as susceptibility to hydrolysis and sensitivity to ultraviolet (UV) light, limiting its application in certain areas. In this study, poly(carbazole diimide) (PCDI) and the epoxy chain extender Joncryl ADR4468 (CE) were employed as a synergistic anti-hydrolysis agent for PLA, and tannic acid (TA) was used as a UV-resistant agent. A melt-blending process was employed to prepare PLA composite materials with enhanced resistance to both hydrolysis and UV radiation. The results indicate that the addition of PCDI-TA-CE significantly improved the performance of PLA. After 8 h of hydrolysis at 80 °C, the tensile strength of PLA increased from 38.31 MPa for pure PLA to 77.69 MPa with the incorporation of PCDI-TA-CE. The elongation at break increased from 0.6% to 1.5%, and the Ultraviolet Protection Factor (UPF) value elevated from 3.19 for pure PLA to 503.46.This demonstrates that PCDI, CE, and TA can effectively enhance the anti-hydrolysis and UV resistance properties of PLA.

The influence of reed nanocellulose on the quality indicators of paper-basis for wallpapers

Improving the production technology of products with improved quality indicators and with less impact on the environment remains an urgent scientific and practical problem of paper industry enterprises. This refers to the technology for the production of paper-bases for wallpaper using environmentally safe chemical additives, in particular nanocellulose (NC), which was obtained by acid hydrolysis from reed cellulose. The production of cellulose was carried out in two stages - extraction from reed stalks with a solution of alkali and an organosolvent method of cooking in a solution of peracetic acid. The obtained organosolvent cellulose contained the remains of lignin and mineral substances, which allows it to be used for the preparation of NC. As a result of the hydrolysis of organosolvent cellulose, a time-stable NC suspension was extracted, the properties of which were investigated by scanning electron microscopy (morphological changes in the structure of reed cellulose-containing materials), atomic force microscopy (determination of topographic characteristics of NC), analysis of electronic absorption spectra (transparency of NC films). It was established that reed NC films had nanoparticles with a cross-sectional size of 5-25 nm, density up to 1.52 g/cm3, transparency up to 81.6 %, tensile strength up to 65 MPa. For the production of castings of paper-bases for wallpaper samples, sulfated pine bleached cellulose and polyester synthetic fiber were used, to the fibrous mass of which were added the following chemical additives: alkyl ketene dimer, reed NC, binder, and optical brightener. It has been shown that the use of nanocellulose at a rate of 0.35 % to 1.0 % of the paper mass leads to a significant improvement in the physical and mechanical quality indicators of the paper base for wallpaper. It was established that the replacement of 50 % of the synthetic chemical auxiliary substance alkyl ketene dimer with nanocellulose or additional application of nanocellulose at a rate of 0.5 g/m2 on the surface of the casting with 0.7 % alkyl ketene dimer allows to obtain paper that meets the requirements of the standard. The obtained results indicate the prospects of using reed nanocellulose for the production of other mass types of paper and cardboard.

Two New Isospirostanol-Type Saponins from the Bulbs of Lilium Brownii and Their Anti-Hepatocarcinogenic Activity.

Bulbs of Lilium brownii, commonly known as "Bai-he" in China, serve both edible and medicinal purposes in clinical practice. In this study, two new isospirostanol-type saponins were isolated from L. brownii, and their structures were identified by spectroscopic method, and absolute configurations were elucidated by comprehensive analysis of spectral data obtained from combined acid hydrolysis. Two compounds were finally identified as 3-O-[α-L-rhamnopyranosyl-(1→2)-β-D-glucopyranoside]-(22R,25R)-5α-spirosolane-3β-ol (1) and 3-O-{α-L-rhamnopyranosyl-(1→2)-[β-D-glucopyranosyl-(1→4)]-β-D-glucopyranoside}-(22R,25R)-5α-spirosolane-3β-ol (2), respectively. Further, we found that compound 2 significantly suppressed the proliferation of SMMC-7721 and HepG2 cells with IC50 values of 26.3±1.08 μM and 30.9±1.59 μM, whereas compound 1 didn't inhibit both of the two hepatocellular carcinoma. Subsequently, compound 2 effectively decreased the levels of interleukin-1β and tumor necrosis factor-α and the expression of Bcl-2, and increased the expression of Bax and Caspase-3 proteins. Which indicated that the anti-hepatocellular carcinoma effect of compound 2 involves reducing the level of inflammation and inducing apoptosis.

Detection and Quantification of Mono-Rhamnolipids and Di-Rhamnolipids Produced by Pseudomonas aeruginosa.

The environmental bacterium Pseudomonas aeruginosa is an opportunistic pathogen with high antibiotic resistance that represents a health hazard. This bacterium produces high levels of biosurfactants known as rhamnolipids (RL), which are molecules with significant biotechnological value but are also associated with virulence traits. In this respect, the detection and quantification of RL may be useful for both biotechnology applications and biomedical research projects. In this article, we demonstrate step-by-step the technique to detect the production of the two forms of RL produced by P. aeruginosa using thin-layer chromatography (TLC): mono-rhamnolipids (mRL), molecules constituted by a dimer of fatty acids (mainly C10-C10) linked to one rhamnose moiety, and di-rhamnolipids (dRL), molecules constituted by a similar fatty acid dimer linked to two rhamnose moieties. Additionally, we present a method to measure the total amount of RL based on the acid hydrolysis of these biosurfactants extracted from a P. aeruginosa culture supernatant and the subsequent detection of the concentration of rhamnose that reacts with orcinol. The combination of both techniques can be used to estimate the approximate concentration of mRL and dRL produced by a specific strain, as exemplified here with the type strains PAO1 (phylogroup 1), PA14 (phylogroup 2), and PA7 (phylogroup 3).

Polypropylene Composites Reinforced with Lignocellulose Nanocrystals of Corncob: Thermal and Mechanical Properties

Composites based on recycled polypropylene (PP) reinforced with cellulose nanocrystals whit lignin corncob were prepared. The effect of the ratio composites prepared via a compression molding process on the mechanical and thermal properties was analyzed. Corncobs is a little-used agroindustrial residue with a high cellulose content. The corncob was milled and then delignified via the organosolve process in order to get the cellulose unbleached. An acid hydrolysis process was then carried out to obtain lignocellulose nanocrystals (LCNCs). Subsequently, LCNC/PP composites were obtained via termocompression molding using different concentrations of LCNC (0, 0.5, 1 and 2% by weight) previously mixed via extrusion. The residual lignin present in the LCNCs improved the compatibility between the reinforcement and the PP matrix. This was evidenced by the increase in mechanical properties and the stabilization of thermal properties. The results of the mechanical tests showed that the LCNC increases the tensile and flexural modules and strength with respect to neat PP. Composites with 2% of LCNC showed an increase of 36% and 43% in modulus and tensile strength, respectively, while the flexural modulus and strength increased by 7.6%. By using reinforcements of natural and residual origin (corncob) and improving the properties of recycled polymers, their reuse will increase, and this can lead to reducing waste in the environment.

Pickering emulsions stabilized by starch nanocrystals prepared from various crystalline starches by ultrasonic assisted acetic acid: Stability and delivery of curcumin

Ultrasonic assisted acetic acid hydrolysis was applied to prepare starch nanocrystals (SNCs) from native starches with different crystalline structures (A, B, and C types). The structure properties, morphology, Pickering emulsion stability and curcumin deliver capacity of both SNCs and native starches were investigated and compared. Compared with native starches, SNCs showed smaller size and higher crystallinity. The size of SNCs varied with different crystalline types, with C-type starch exhibiting the smallest SNCs (107.4 nm), followed by A-type (113.8 nm), and B-type displaying the largest particle size (149.0 nm). SNCs-Pickering emulsion showed enhanced stability with smaller emulsion droplets, higher static stability, and denser oil/water interface. SNCs-Pickering emulsions displayed higher curcumin loading efficiency (53.53 %–61.41 %) compared with native starch-Pickering emulsions (13.93 %–19.73 %). During in vitro digestion, SNCs-Pickering emulsions proved to be more proficient in protecting and prolonging the biological activity of curcumin due to their smaller size and better interfacial properties. These findings demonstrated the potential of SNCs for application in Pickering emulsion and delivery of bioactive components.

Renewing the potential of rice crop residues as value-added products in the cosmetics industry

Purpose of this study is to explore the extraction of potentially valuable cosmetic ingredients from rice crop residues, aiming to mitigate their environmental impact. MethodsWe employed AOAC methods to analyze the fat, protein, ash, fiber, soluble, and insoluble carbohydrate content in these residues. To identify sugars rich in galactose and acidic sugars, a total soluble carbohydrate extraction was performed. Cellulose, as part of the insoluble carbohydrates, was isolated through alkaline and acid hydrolysis, while sodium silicate was derived from the ash. Characterization of insoluble cellulose and silicate involved techniques like FTIR, DSC, PXRD, microphotography, porosity assessments, and water absorption studies. For proteins, alkaline solubilization and precipitation at the isoelectric point were utilized, with quantification via BCA and amino acid profiling through gas chromatography. Evaluation of radical scavenging capacity using DPPH led to the calculation of apparent molecular weight via SDS-PAGE. ResultsThe results revealed low levels of gum, mucilage, and pectin in both residues, contrasting with a high concentration of insoluble polysaccharides. Among these, Iβ cellulose displayed potential attributes for cosmetic applications due to its oil and water adsorption characteristics. However, silicates obtained from the ashes did not exhibit direct use potential. In terms of protein extraction, we observed antioxidant properties, with enhanced performance through enzymatic hydrolysis, achieving a hydrolysis degree of 30.41% and a DPPH radical absorption rate exceeding 70%. ConclusionRice residues, particularly husk and straw, shown valuable substances suitable for potential cosmetic applications, encompassing cellulose, hydrolyzed proteins, and ash as a silicate precursor.

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 , an , and a mechanism 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