Subjects -> CHEMISTRY (Total: 986 journals)
    - ANALYTICAL CHEMISTRY (59 journals)
    - CHEMISTRY (713 journals)
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    - ELECTROCHEMISTRY (28 journals)
    - INORGANIC CHEMISTRY (45 journals)
    - ORGANIC CHEMISTRY (47 journals)
    - PHYSICAL CHEMISTRY (71 journals)

CHEMISTRY (713 journals)                  1 2 3 4 | Last

Showing 1 - 200 of 735 Journals sorted alphabetically
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 29)
ACS Applied Polymer Materials     Hybrid Journal   (Followers: 9)
ACS Catalysis     Hybrid Journal   (Followers: 51)
ACS Chemical Neuroscience     Hybrid Journal   (Followers: 21)
ACS Combinatorial Science     Hybrid Journal   (Followers: 21)
ACS Environmental Au     Open Access  
ACS Macro Letters     Hybrid Journal   (Followers: 25)
ACS Materials Letters     Open Access   (Followers: 2)
ACS Medicinal Chemistry Letters     Hybrid Journal   (Followers: 43)
ACS Nano     Hybrid Journal   (Followers: 190)
ACS Photonics     Hybrid Journal   (Followers: 15)
ACS Symposium Series     Full-text available via subscription   (Followers: 3)
ACS Synthetic Biology     Hybrid Journal   (Followers: 28)
Acta Chemica Malaysia     Open Access  
Acta Chimica Slovaca     Open Access   (Followers: 2)
Acta Chimica Slovenica     Open Access   (Followers: 2)
Acta Chromatographica     Full-text available via subscription   (Followers: 7)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 8)
Acta Scientifica Naturalis     Open Access   (Followers: 2)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 7)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 9)
Advanced Electronic Materials     Hybrid Journal   (Followers: 5)
Advanced Functional Materials     Hybrid Journal   (Followers: 70)
Advanced Journal of Chemistry, Section A     Open Access   (Followers: 3)
Advanced Journal of Chemistry, Section B     Open Access   (Followers: 1)
Advanced Science Focus     Free   (Followers: 5)
Advanced Theory and Simulations     Hybrid Journal   (Followers: 2)
Advanced Therapeutics     Hybrid Journal   (Followers: 1)
Advances in Chemical Engineering and Science     Open Access   (Followers: 104)
Advances in Chemical Science     Open Access   (Followers: 50)
Advances in Chemistry     Open Access   (Followers: 34)
Advances in Chemistry     Full-text available via subscription   (Followers: 4)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 16)
Advances in Environmental Chemistry     Open Access   (Followers: 9)
Advances in Enzyme Research     Open Access   (Followers: 10)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 8)
Advances in Materials Physics and Chemistry     Open Access   (Followers: 31)
Advances in Nanoparticles     Open Access   (Followers: 17)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 18)
Advances in Polymer Science     Hybrid Journal   (Followers: 50)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 18)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 6)
Advances in Science and Technology     Full-text available via subscription   (Followers: 16)
Aerosol Science and Engineering     Hybrid Journal  
African Journal of Bacteriology Research     Open Access  
African Journal of Chemical Education     Open Access   (Followers: 5)
African Journal of Pure and Applied Chemistry     Open Access   (Followers: 6)
Aggregate     Open Access   (Followers: 1)
Agrokémia és Talajtan     Full-text available via subscription   (Followers: 2)
Al-Kimia : Jurnal Penelitian Sains Kimia     Open Access  
Alchemy : Journal of Chemistry     Open Access   (Followers: 3)
Alchemy : Jurnal Penelitian Kimia     Open Access  
Alotrop     Open Access  
AMB Express     Open Access   (Followers: 1)
Ambix     Hybrid Journal   (Followers: 3)
American Journal of Biochemistry and Biotechnology     Open Access   (Followers: 43)
American Journal of Biochemistry and Molecular Biology     Open Access   (Followers: 20)
American Journal of Chemistry     Open Access   (Followers: 37)
American Journal of Plant Physiology     Open Access   (Followers: 7)
Analyst     Hybrid Journal   (Followers: 36)
Analytical Science Advances     Open Access   (Followers: 1)
Angewandte Chemie     Hybrid Journal   (Followers: 156)
Angewandte Chemie International Edition     Hybrid Journal   (Followers: 228)
Annales Universitatis Mariae Curie-Sklodowska, sectio AA – Chemia     Open Access   (Followers: 1)
Annals of Clinical Chemistry and Laboratory Medicine     Open Access   (Followers: 6)
Annual Reports in Computational Chemistry     Full-text available via subscription   (Followers: 4)
Annual Review of Chemical and Biomolecular Engineering     Full-text available via subscription   (Followers: 12)
Annual Review of Food Science and Technology     Full-text available via subscription   (Followers: 14)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 7)
Applied Surface Science     Hybrid Journal   (Followers: 30)
Arabian Journal of Chemistry     Open Access   (Followers: 4)
ARKIVOC     Open Access   (Followers: 1)
Asian Journal of Applied Chemistry Research     Open Access   (Followers: 2)
Asian Journal of Biochemistry     Open Access   (Followers: 2)
Asian Journal of Chemical Sciences     Open Access   (Followers: 1)
Asian Journal of Chemistry and Pharmaceutical Sciences     Open Access  
Asian Journal of Physical and Chemical Sciences     Open Access   (Followers: 2)
Atomization and Sprays     Full-text available via subscription   (Followers: 7)
Australian Journal of Chemistry     Hybrid Journal   (Followers: 7)
Autophagy     Hybrid Journal   (Followers: 7)
Avances en Quimica     Open Access  
Biochemical Pharmacology     Hybrid Journal   (Followers: 11)
Biochemistry     Hybrid Journal   (Followers: 205)
Biochemistry Research International     Open Access   (Followers: 5)
BioChip Journal     Hybrid Journal  
Bioinorganic Chemistry and Applications     Open Access   (Followers: 5)
Biointerface Research in Applied Chemistry     Open Access  
Biointerphases     Open Access   (Followers: 1)
Biology, Medicine, & Natural Product Chemistry     Open Access   (Followers: 2)
Biomacromolecules     Hybrid Journal   (Followers: 22)
Biomass Conversion and Biorefinery     Partially Free   (Followers: 10)
Biomedical Chromatography     Hybrid Journal   (Followers: 6)
Biomolecular NMR Assignments     Hybrid Journal   (Followers: 3)
BioNanoScience     Partially Free   (Followers: 3)
Bioorganic & Medicinal Chemistry     Hybrid Journal   (Followers: 93)
Bioorganic & Medicinal Chemistry Letters     Hybrid Journal   (Followers: 66)
Bioorganic Chemistry     Hybrid Journal   (Followers: 9)
Biopolymers     Hybrid Journal   (Followers: 15)
Biosensors     Open Access   (Followers: 3)
Biotechnic and Histochemistry     Hybrid Journal   (Followers: 1)
Bitácora Digital     Open Access  
Boletin de la Sociedad Chilena de Quimica     Open Access  
Bulletin of Institute of Chemistry and Chemical Technology, Mongolian Academy of Sciences     Open Access  
Bulletin of the Chemical Society of Ethiopia     Open Access   (Followers: 1)
Bulletin of the Chemical Society of Japan     Full-text available via subscription   (Followers: 24)
Bulletin of the Korean Chemical Society     Hybrid Journal   (Followers: 1)
C - Journal of Carbon Research     Open Access   (Followers: 5)
Cakra Kimia (Indonesian E-Journal of Applied Chemistry)     Open Access  
Canadian Journal of Chemistry     Hybrid Journal   (Followers: 12)
Canadian Mineralogist     Full-text available via subscription   (Followers: 5)
Carbohydrate Polymer Technologies and Applications     Open Access  
Carbohydrate Polymers     Hybrid Journal   (Followers: 8)
Carbohydrate Research     Hybrid Journal   (Followers: 24)
Carbon     Hybrid Journal   (Followers: 65)
Carbon Capture Science & Technology     Open Access   (Followers: 6)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 9)
Catalysis Science and Technology     Hybrid Journal   (Followers: 9)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 4)
Catalysts     Open Access   (Followers: 11)
Cell Reports Physical Science     Open Access  
Cellulose     Hybrid Journal   (Followers: 8)
Cereal Chemistry     Full-text available via subscription   (Followers: 4)
Chem     Hybrid Journal   (Followers: 10)
Chem Catalysis     Hybrid Journal   (Followers: 7)
ChemBioEng Reviews     Full-text available via subscription   (Followers: 3)
ChemCatChem     Hybrid Journal   (Followers: 8)
Chemical and Engineering News     Free   (Followers: 21)
Chemical Bulletin of Kazakh National University     Open Access  
Chemical Communications     Hybrid Journal   (Followers: 81)
Chemical Engineering Research and Design     Hybrid Journal   (Followers: 25)
Chemical Physics Impact     Full-text available via subscription   (Followers: 6)
Chemical Research in Chinese Universities     Hybrid Journal   (Followers: 4)
Chemical Research in Toxicology     Hybrid Journal   (Followers: 22)
Chemical Reviews     Hybrid Journal   (Followers: 176)
Chemical Science     Open Access   (Followers: 39)
Chemical Science International Journal     Open Access  
Chemical Technology     Open Access   (Followers: 74)
Chemical Thermodynamics and Thermal Analysis     Open Access   (Followers: 8)
Chemical Vapor Deposition     Hybrid Journal   (Followers: 4)
Chemie in Unserer Zeit     Hybrid Journal   (Followers: 54)
Chemie-Ingenieur-Technik (Cit)     Hybrid Journal   (Followers: 21)
ChemInform     Hybrid Journal   (Followers: 5)
Chemistry & Biodiversity     Hybrid Journal   (Followers: 7)
Chemistry & Industry     Full-text available via subscription   (Followers: 6)
Chemistry - A European Journal     Hybrid Journal   (Followers: 124)
Chemistry - An Asian Journal     Hybrid Journal   (Followers: 19)
Chemistry Africa : A Journal of the Tunisian Chemical Society     Hybrid Journal  
Chemistry and Materials Research     Open Access   (Followers: 17)
Chemistry Central Journal     Open Access   (Followers: 4)
Chemistry Education Research and Practice     Free   (Followers: 6)
Chemistry Education Review     Open Access   (Followers: 1)
Chemistry in Education     Open Access   (Followers: 3)
Chemistry Letters     Full-text available via subscription   (Followers: 44)
Chemistry of Heterocyclic Compounds     Hybrid Journal   (Followers: 5)
Chemistry of Materials     Hybrid Journal   (Followers: 162)
Chemistry of Natural Compounds     Hybrid Journal   (Followers: 10)
Chemistry World     Hybrid Journal   (Followers: 20)
Chemistry-Didactics-Ecology-Metrology     Open Access  
ChemistryOpen     Open Access   (Followers: 1)
ChemistrySelect     Hybrid Journal   (Followers: 1)
Chemistry–Methods     Open Access   (Followers: 1)
Chemkon - Chemie Konkret, Forum Fuer Unterricht Und Didaktik     Hybrid Journal  
ChemNanoMat     Hybrid Journal   (Followers: 1)
Chemoecology     Hybrid Journal   (Followers: 2)
Chemometrics and Intelligent Laboratory Systems     Hybrid Journal   (Followers: 13)
ChemPhotoChem     Hybrid Journal  
ChemPhysChem     Hybrid Journal   (Followers: 12)
ChemPhysMater     Full-text available via subscription   (Followers: 9)
ChemPlusChem     Hybrid Journal   (Followers: 2)
Chempublish Journal     Open Access  
ChemSystemsChem     Hybrid Journal   (Followers: 1)
ChemTexts     Hybrid Journal   (Followers: 1)
CHIMIA International Journal for Chemistry     Open Access   (Followers: 2)
Chinese Journal of Chemistry     Hybrid Journal   (Followers: 6)
Chinese Journal of Polymer Science     Hybrid Journal   (Followers: 9)
Chromatographia     Hybrid Journal   (Followers: 22)
Chromatography     Open Access   (Followers: 2)
Chromatography Research International     Open Access   (Followers: 4)
Ciencia     Open Access  
Clay Minerals     Hybrid Journal   (Followers: 7)
Cogent Chemistry     Open Access   (Followers: 3)
Colloid and Interface Science Communications     Open Access  
Colloid and Polymer Science     Hybrid Journal   (Followers: 6)
Colloids and Surfaces B: Biointerfaces     Hybrid Journal   (Followers: 8)
Combinatorial Chemistry & High Throughput Screening     Hybrid Journal   (Followers: 2)
Combustion Science and Technology     Hybrid Journal   (Followers: 26)
Comments on Inorganic Chemistry: A Journal of Critical Discussion of the Current Literature     Hybrid Journal   (Followers: 1)
Communications Chemistry     Open Access   (Followers: 2)
Communications Materials     Open Access  
Composite Interfaces     Hybrid Journal   (Followers: 6)
Comptes Rendus : Chimie     Open Access  
Comptes Rendus : Physique     Open Access   (Followers: 2)
Computational and Theoretical Chemistry     Hybrid Journal   (Followers: 11)
Computational Biology and Chemistry     Hybrid Journal   (Followers: 13)
Computational Chemistry     Open Access   (Followers: 4)
Computers & Chemical Engineering     Hybrid Journal   (Followers: 11)
Coordination Chemistry Reviews     Full-text available via subscription   (Followers: 6)
Corrosion Communications     Open Access   (Followers: 6)
Critical Reviews in Biochemistry and Molecular Biology     Hybrid Journal   (Followers: 17)
Croatica Chemica Acta     Open Access  

        1 2 3 4 | Last

Similar Journals
Journal Cover
Biomass Conversion and Biorefinery
Journal Prestige (SJR): 0.493
Citation Impact (citeScore): 1
Number of Followers: 10  
 
  Partially Free Journal Partially Free Journal
ISSN (Print) 2190-6815 - ISSN (Online) 2190-6823
Published by Springer-Verlag Homepage  [2468 journals]
  • Comparative study on physicochemical hydrolysis methods for glycerides
           removal from rice bran acid oil for subsequent γ-oryzanol recovery

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      Abstract: A comparative study on physicochemical hydrolysis methods, including acid-catalyzed, base-catalyzed, and subcritical water hydrolysis, for glycerides removal prior to subsequent γ-oryzanol purification from rice bran acid oil (RBAO), is presented. The effects of hydrolysis conditions on the residual levels of glycerides and γ-oryzanol in RBAO were first investigated for each method. It can be concluded that the acid-catalyzed hydrolysis was not a suitable hydrolysis method for this application as it provided a low glycerides conversion level of ca. 30% using 2 N H2SO4 at 80–100 °C, despite the long reaction time (> 60 min). For the base-catalyzed hydrolysis, 100% glycerides removal was achieved at the most suitable condition, which was suggested to be at 2.5 N NaOH, 90 °C and 5–10 min. At this condition, a relatively high residual level of γ-oryzanol of ca. 57–66% was obtained. For the subcritical water hydrolysis, the results suggested that γ-oryzanol was hydrolyzed more rapidly than glycerides, and the most suitable condition for subcritical water hydrolysis was at 220 °C for 10 min. At this condition, high glycerides removal of > 95% was achieved while the remaining amount of γ-oryzanol was still acceptable (50%).
      PubDate: 2022-02-01
       
  • Insight into papermaking characteristics of D0EPD1-bleached soda, soda-AQ
           and kraft pulps of citronella grass (Cymbopogon winterianus Jowitt)

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      Abstract: Grasses have emerged as potential alternative raw materials which can replace wood for pulp and paper products. Various species of grasses have been explored previously for pulp and paper production. This study is aimed to investigate pulp and papermaking characteristics of a grass species namely Cymbopogon winterianus Jowitt which is commonly known as citronella grass. This grass was subjected to proximate chemical characterisation; fibre morphology analysis; soda, soda-AQ (soda-anthraquinone), and kraft pulping; elemental chlorine free bleaching using D0EPD1 (D = ClO2 in acidic medium; EP = alkaline extraction with addition of H2O2; 0 and 1 = initial and final stage) sequence; and evaluation of physical strength properties of paper hand sheets. The pulp and paper hand sheets were also examined through SEM (scanning electron microscope) and FTIR (Fourier-transform infrared) spectroscopy to observe the structural and functional group variations. The proximate chemical analysis of citronella grass was found superior in terms of α-cellulose (38.10%), pentosans (22.30%) and alkali solubility (28.20%) while inferior in terms of ash (8.20%), lignin (25.10%) and alcohol benzene solubility (6.31%) with respect to some other grass species used for pulp and papermaking. Fibre length (0.69–0.74 mm) and fibre width (13.8–15.1 μm) were also comparable to other grass species. Brown pulp characteristics such as screened yield (44.67%), brightness (~24 %ISO) and kappa number (~20) revealed superiority of soda-AQ pulping among all the pulping processes while the kraft pulp exhibited the highest brightness (83.05 %ISO) and intrinsic viscosity (17.6 cP) after D0EPD1 bleaching. Tear index, tensile index and burst index of paper hand sheets obtained from bleaching of soda-AQ and kraft pulps were almost similar but higher to that of bleached soda pulp. The citronella grass was found suitable for producing writing and printing grade paper based on processes and optimised parameters described in this study.
      PubDate: 2022-02-01
       
  • Pyrolysed almond shells used as electrodes in microbial electrolysis cell

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      Abstract: The large cost of components used in microbial electrolysis cell (MEC) reactors represents an important limitation that is delaying the commercial implementation of this technology. In this work, we explore the feasibility of using pyrolysed almond shells (PAS) as a material for producing low-cost anodes for use in MEC systems. This was done by comparing the microbial populations that developed on the surface of PAS bioanodes with those present on the carbon felt (CF) bioanodes traditionally used in MECs. Raw almond shells were pyrolysed at three different temperatures, obtaining the best conductive material at the highest temperature (1000 °C). The behaviour of this material was then verified using a single-chamber cell. Subsequently, the main test was carried out using two-chamber cells and the microbial populations extant on each of the bioanodes were analysed. High-throughput sequencing of the 16S rRNA gene for eubacterial populations was carried out in order to compare the microbial communities attached to each type of electrode. The microbial populations on each electrode were also quantified by real-time polymerase chain reaction (real-time PCR) to determine the amount of bacteria capable of growing on the electrodes’ surface. The results indicated that the newly developed PAS bioanodes possess a biofilm similar to those found on the surface of traditional CF electrodes.
      PubDate: 2022-02-01
       
  • Biodiesel production from the Chlorella vulgaris and Spirulina platensis
           microalgae by electrolysis using CaO/KOH-Fe3O4 and KF/KOH-Fe3O4 as
           magnetic nanocatalysts

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      Abstract: Based on the results from recent studies on biodiesel production, in addition to cost reduction, the electrolysis method has both quantitative and qualitative advantages over the reflux method. Thus, in this study, biodiesel was produced by the electrolysis of the oil of two sea microalgae strains, namely Chlorella vulgaris and Spirulina platensis, using methanol and prepared CaO/KOH-Fe3O4 and KF/KOH-Fe3O4 magnetic nanocatalysts. At the first step, magnetic nanocatalysts were prepared, Scanning electron microscope and X-ray diffraction patterns of the prepared nanocatalysts were studied, and the calculated average crystal size of CaO/KOH-Fe3O4 and KF/KOH-Fe3O4 was 55.91 nm and 42 nm, respectively. Brunauer-Emmett-Teller analysis was performed for the determination of the active surface area. Then, two types of mentioned nonfood microalgae were cultured, and the oil of them was extracted. The most suitable microalgae between these two types with regard to the culture condition was chosen for the last step. Then, electrolysis technique contains two graphite plate electrodes (3 cm × 3 cm) that are separated by a distance of 2 cm and potential difference of 54 V with the electrolysis cell which was filled with 100 mL of reaction mixture containing methanol, the aforementioned microalgae oil, Tetrahydrofuran (THF), water, and nanocatalysts was performed for biodiesel production. The effect of catalyst weight percentage (1, 1.5, 2 wt%), molar ratio of alcohol to oil (5:1, 6:1, 7:1), and the reaction time (30, 60, 120, 180 min) in the efficiency of biodiesel production was investigated, and the physical properties of the prepared biodiesel were quantified. Based on the results, Chlorella vulgaris microalgae because of the more obtainable oil shows the priority of microalgae over Spirulina platensis and KF/KOH-Fe3O4 is an optimal choice catalyst for biodiesel production. The optimal condition was using 1.5 wt% of catalyst, methanol/oil molar ratio of 1:6, temperature of 25 °C, stirring speed of 400 rpm, and the reaction time of 2 h. Furthermore, B20 was prepared using the obtained biodiesel, and the quality was in accordance with the world standard of fuel ASTM D975, with the process yield of 96.8%, and no saponification side reaction, and KF/KOH-Fe3O4 showed the higher mass yield in transesterification reaction.
      PubDate: 2022-02-01
       
  • Compound enzymatic hydrolysis of feather waste to improve the nutritional
           value

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      Abstract: Although feather waste is generated abundantly but rich in natural protein, it is hassled to be digested. To improve the nutritional value of feather waste, compound enzymatic hydrolysis (CEH) was applied to degrade feather waste. Results indicated that the nutritional value of feather meal (FM) produced with CEH was improved in terms of protein solubility increase to 20.75 times and in vitro protein digestibility increase to 10.27 times as compared to fresh FM; this improvement was ascribed to the keratinase breaking up disulfide bond and compound enzymes destroying the smooth surface structure, compact β-sheet structure, and hydrogen bond. In conclusion, CEH is an effective and promising approach to improve the nutrient value of feather waste. The results shed light on the utilization of feather waste for protein resource in feed industry.
      PubDate: 2022-02-01
       
  • Effect of the operating conditions on the anaerobic digestion of
           wheatgrass for chemicals and energy production

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      Abstract: The aim of this study was to investigate anaerobic digestion of wheatgrass in the absence of hydrolytic pre-treatments. The effect of solids retention time (SRT) (1–64 days), inoculum acclimation (0–80 days acclimation), temperature (40–70 °C) and buffer capacity (20–200 mM phosphate buffer) on conversion of the feedstock, yield and composition of liquid-phase products (ethanol and short-chain organic acids, SCOAs) and COD removal was investigated in semi-continuous (intermittent feed) completely mixed reactors. SRT had the most important effect on process performance. Biodegradation of the feedstock was favoured at high SRT, with 61% removal of volatile suspended solids and 84% removal of total carbohydrates at SRT 64 days. However, low yield of liquid-phase products was observed at high SRT because of strong methanogenic activity (57% removal of the total COD). The highest yield of liquid-phase products was 20% (COD basis) at SRT 8 days. Although high biodegradation of the feedstock was observed after long-term batch acclimation (30 and 80 days), once the digestion conditions were switched to semi-continuous at short SRT (2 days), the biodegradation of the feedstock decreased considerably. The best process performance was observed at 40 °C.
      PubDate: 2022-02-01
       
  • Evaluation of orange and potato peels as an energy source: a comprehensive
           study on their pyrolysis characteristics and kinetics

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      Abstract: The orange and potato peels can be evaluated as raw materials in pyrolysis process to produce sustainable fuels and chemicals. The present study focuses on determining pyrolysis characteristics and kinetics of orange and potato peels. Thus, thermogravimetric analyses of said peels were studied from ambient temperature to 650°C at 2, 10 and 15°C/min heating rates under N2 atmosphere. The studies revealed that the thermal decomposition of orange peels occurs in four stages whereas potato peels decompose in three stages. The second and third stages of orange peel pyrolysis and the second stage of potato peel pyrolysis were determined as active pyrolysis stages. The kinetic parameters of active pyrolysis stages were calculated by direct Arrhenius plot, Coats-Redfern, Friedman and Kissinger-Akahira-Sunose methods. The average activation energies calculated by all methods were relatively in good agreement for second stages, but the same cannot be said for the third stage of orange peel pyrolysis. Considering the conversion values based on volatiles and the calculated average activation energy values, the orange and potato peels were projected to be valuable and sustainable energy sources which can be evaluated by pyrolysis process.
      PubDate: 2022-02-01
       
  • Citric acid-based deep eutectic solvent for the anthocyanin recovery from
           Hibiscus sabdariffa through microwave-assisted extraction

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      Abstract: In the current study, Hibiscus sabdariffa has been extracted by microwave-assisted extraction (MAEX). Citric acid-based deep eutectic solvents (DES) have been specially designed, where a hydrogen bond donor (HBD) (glycerol and ethylene glycol) and a hydrogen bond acceptor (HBA) (citric acid) with a certain molar ratio (1/4) were used. After the best DES (citric acid/ethylene glycol) has been decided to extract the bioactive ingredients, operation conditions (power of microwave, volume of solvent water and content in the DES) of the MAEX for the relevant plant material have been optimized through Box-Behnken design (BBD) of response surface approach (RSA). The maximum yields of total phenolics (TP), total anthocyanins (TAA) and antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) have been found as 31.897 mg-GAE/g-DH, 2.961 mg-C3G/g-DH and 95.887% under the optimal conditions (35 mL DES including 50% water (v/v) at 550 W power of microwave). The differences between the experimental and estimated findings were lower than 2%. Three replicate test results obtained by in vitro experiments were also statistically analysed by using one-way analysis of variance (ANOVA) test. Graphical abstract
      PubDate: 2022-02-01
       
  • Effect of enzymatic pretreatment of sugarcane bagasse with recombinant
           hemicellulases and esterase prior to the application of the
           cellobiohydrolase CBH I Megazyme®

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      Abstract: The polysaccharides in the primary plant cell wall are a renewable energy source for biofuel production. However, these polysaccharides are not readily available for bioconversion, and large enzyme sets are required to deconstruct them. Here, we aimed to improve the glucan conversion using recombinant hemicellulases and esterase as a treatment in exploded and sugarcane bagasses (SCB), followed by the addition of commercial CBH I to prevent its inhibition by hemicellulases products. A high secretion level of the recombinant enzymes was observed on SDS-PAGE. The highest activities were verified at a temperature and pH ranging from 40 to 55 °C and 4.5 to 6.0, respectively. The released reducing sugar analysis showed that all enzymes act better on SCB, with xylanase C (XynC) presenting the best activity (0.54 U/mg of protein). The high-performance liquid chromatography (HPLC) analysis demonstrated that 24 h of pretreatment was enough to reach maximum glucan conversion. The best synergy was achieved between XynC and CBH I on SCB, 1.4%. All results showed that the enzymes acted better on SCB, which can be related to the biomass composition and its molecular structure. The enzymatic pretreatment of SCB with XynC was essential to improve the glucan conversion by CBH I.
      PubDate: 2022-02-01
       
  • Biotransformation of agro-industrial waste to produce lignocellulolytic
           enzymes and bioethanol with a zero waste

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      Abstract: The use of lignocellulosic wastes reduces dependence on fossil fuel resources, contributes to sustainable waste management, and reinforces the circular economy model of continual use of resources. Typically, the second generation of bioethanol production involves several steps to transform lignocellulosic material into bioethanol. The more complicated step of the overall process is to define a tailor-made to each lignocellulosic material available with a wide variety of complex structures of the lignin, hemicellulose, and cellulose. However, the thermochemicals are the most frequently reported pretreatments, and they have the bottleneck of producing an additional waste stream with a high charge of pollution owing to chemical products implicated. This problem harms on the zero waste policy that we must include in our technological process to be considered sustainable and ecological processes. Consolidated bioprocessing (CBP) is a viable alternative to produce bioethanol from lignocellulosic materials, using a single microorganism, in one-step, and no chemical products are implied. Three agro-industrial wastes with lignocellulosic characteristics were evaluated as a substrate for bioethanol production with a Mexican native white-rot fungus Trametes hirsuta CS5 in a one-step process. Qualitative and quantitative analyses of lignocellulolytic enzymes produced by native fungus were carried out. Instead, Trametes hirsuta is a lignin degrader white-rot fungus; it was capable to produce until 500 U/L of cellulase titers and a maximum xylanase activity of 45 U/mL when it was cultivated in orange peel substrate. Substantial ethanol yields were achieved using lignocellulosic materials like brewer’s spent grain (BSG), orange peel (OP), and wheat bran (WB) as a carbon source in fermentation with no chemicals, which represents a zero waste environment-friendly ethanol production system. Ethanol yield on wheat bran was the highest of all evaluated substrates, reaching value of 34.9% at 7 days, being T. hirsuta able to degrade other hexoses and pentoses present in the structural polymers of cellulose and hemicellulose.
      PubDate: 2022-02-01
       
  • Single-pot conversion of fruit peel waste to 5-hydroxymethylfurfural
           catalyzed by modified activated carbon in green solvent: kinetics and
           thermodynamic study

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      Abstract: The present study investigates one-pot depolymerization of fruit peel waste, namely pineapple (Ananas comosus) and banana (Musa acuminata) peel, for the formation of reducing sugars (TRS) and finally to 5-hydroxymethylfurfural (HMF). The combination of ionic liquid catalyzed by chemically treated activated carbon during dilute acid hydrolysis of fruit peel wastes for the formation of value-added products was evaluated. Physicochemical changes were also determined using FTIR, XRD, and lignocellulosic composition before and after treatment of biomass species. Percentage change in lignocellulosic composition attributes the reduction in crystallinity toward the amorphous region and, hence, increases product yield. Results also reveal significant changes in biomass matrix under different operating conditions, and maximum product yield was observed to be 47.82% and 42.12% (HMF) for pineapple and banana peel, respectively, using optimized ratio of ionic liquid/catalyst as 20 (IL dose 1.5 g) in a hydrolysis time of 90 min at 110 °C. The addition of dilute acid with an appropriate amount and ratio of ionic liquid further improves product yield. The optimum amount of ionic liquid reduced to 1 g from 1.5 g using 4 mL of H3PO4 acid. Kinetic parameters reveal the in situ view of rate constants with increase in temperature and acid strength and were simulated with the Saemen model with coefficient of determination > 0.94 for the rate of sugar formation and degradation. Thermodynamic parameters were also evaluated under the same reaction conditions and the change in ΔSo revealed invariable phase and volume change throughout the reaction process, whereas change in Gibbs free energy indicates a nonspontaneous process. This study provides sustainable and cost-effective production of value-added products with application in biorefinery.
      PubDate: 2022-02-01
       
  • Biogas production from straw—the challenge feedstock pretreatment

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      Abstract: Straw fermentation offers the advantage to provide energy for the electricity, the heat, and/or the mobility sector, while contributing in parallel to close nutrient and humus cycles in agriculture. In this study, the state of technology of straw biogas fermentation is assessed. The results show that the selection of an adequate pretreatment process is one of the main key factors for a successful provision of biogas from straw. The subsequent assessment of three pretreatment options (i.e., mechanical treatment, steam explosion, alkaline treatment) shows that a mechanical pretreatment is economically more viable than the other options, even though the expected biogas yield is clearly lower. This is mainly because chemical or thermal pretreatment results in high investment cost due to high pressure or long residence times. Graphical abstract
      PubDate: 2022-02-01
       
  • An advanced approach for the recovery of acetic acid from its aqueous
           media: deep eutectic liquids versus ionic liquids

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      Abstract: Green chemistry era forces scientists to develop and apply new media in recovery of high-added value materials. It is interesting to utilize deep eutectic liquids (DELs), which have advantages of biodegradability and very low toxicity and ease of use, in separating these fine materials from a complex environment. DELs have been specially designed and used for the extraction of recovery of acetic acid (AA) from its aqueous solutions. Two DELs containing the same hydrogen bond donor-HBD (glycerol) and two different hydrogen bond acceptor-HBA (a quaternary ammonium salt and an amine-based) have been designed with a molar ratio of 1:2. The tailor-designed extractants were diluted with diethyl adipate (DEA), diethyl malonate (DEM), and diethyl succinate (DES), respectively. Extraction efficiency of the diluents has been increased more than 4 times. To compare the results with that of the ionic liquid (IL), 1-hexyl-3-methylimidazolium bromide has been used in the same organic solvents. Efficiencies of the DELs have surpassed 1.4 to 4 times over the IL. Graphical abstract
      PubDate: 2022-02-01
       
  • Anaerobic co-digestion of mango leaves and pig manure: performance
           assessment and kinetic analysis

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      Abstract: Anaerobic batch co-digestion of mango leaves (ML) and pig manure (PM) at 37 °C with five different ML:PM ratios (1:0, 3:1, 1:1, 1:3, and 0:1) was evaluated for the first time. Five different kinetic models were used (first-order kinetic, cone, modified Gompertz, logistic, and transference models) to find the kinetic parameters for the co-digestion of ML and PM. The methane production results proved that the addition of PM highly improved the ML methane production; the highest biodegradability and methane yield of 86% and 465 mL CH4 g−1 VS, respectively, were obtained at ML:PM ratio of 1:3, which were 160%, 26.5%, 19%, and 72% and 196%, 37%, 24%, and 66% higher than those of 1:0, 3:1, 1:1, and 0:1 mixing ratios, respectively. The cone model (as proved by low root mean square error (RMSE) and Akaike’s Information Criterion (AIC)) showed a better fit to the experimental data. The results of the present work showed the synergistic effect of co-digestion to enhance anaerobic degradation of mango leaves and pig manure for biogas production, providing a practical basis for an energy-efficient strategy for bio-waste management.
      PubDate: 2022-02-01
       
  • Application of Box-Behnken design in optimization of biodiesel yield using
           WO3/graphene quantum dot (GQD) system and its kinetics analysis

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      Abstract: In the current research, we report on the synthesis of WO3/GQD system as a heterogeneous catalyst for the transesterification of waste cooking oil into biodiesel using methanol. The characterization of the prepared catalyst was done by X-ray diffraction (XRD), Raman spectroscopy, transmission electron microscope (TEM), energy-dispersive X-ray (EDX), Fourier transform-infrared spectroscopy (FT-IR) techniques, and Brunauer-Emmett-Teller surface area measurement. To study the effect of process variables such as methanol to oil ratio, reaction temperature, and time, we have employed response surface methodology (RSM) based on Box-Behnken design (BBD). The suitability of the predicted model was verified, and the average biodiesel yield of (96.8 ± 0.16%) was reported at optimal reaction condition of 1:6 oil to methanol ratio, 70 °C reaction temperature, 2 wt% catalyst loading, and 3.5 h reaction time. Biodiesel was characterized using proton nuclear magnetic resonance (1H NMR) and carbon nuclear magnetic resonance (13C NMR) techniques, and fatty acid methyl ester composition was determined using gas chromatography-mass spectrometry (GC-MS). Fuel properties of the biodiesel obtained comply with ASTMD6751 biodiesel standards. The kinetics of transesterification was studied and found to follow pseudo-first order. The results showed the rate constant ranging from 0.0028 to 0.007 min−1, activation energy (Ea) of 55.92 kJ mol−1, and frequency factor (A) of 1.72 × 106 min−1. Graphical abstract
      PubDate: 2022-02-01
       
  • Synergistic effect of acidity balance and hydrothermal pretreatment
           severity on alkali extraction of hemicelluloses from corn stalk

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      Abstract: The current hemicelluloses extraction methods have problems such as low extraction ratio and quality. In the previous study, a new pH pre-corrected hydrothermal pretreatment has been proved effective in improving enzymatic hydrolysis of cellulose while retaining higher hemicelluloses without degradation. In this investigation, the synergistic effect of alkali loading and hydrothermal pretreatment severity on hemicelluloses preservation was studied. After pretreatment, the hemicelluloses were extracted with alkali. The results show that hemicelluloses extracted with 10% (w/v) NaOH after pH pre-corrected hydrothermal pretreatment at the severity of 2.0 contained no cellulose. At this condition, the ratios of hemicelluloses dissolution and recovery were the highest. The extracted hemicelluloses had the lowest color value, branch degree, and polydispersity.
      PubDate: 2022-02-01
       
  • Micro-assay method for enzymatic saccharification of industrially relevant
           lignocellulose substrates

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      Abstract: The development of micro-assays suitable for automation systems represents a helpful alternative by which many enzymes and factors can be studied simultaneously for the conversion of lignocellulose. The purpose of the present study was to evaluate a micro-assay method, based on hand-sheets, to reproducibly aliquot-pretreated lignocellulosic biomass at milligramme scale with minimal impact on the digestibility of the material. To favour representative sampling and handling for enzymatic conversion at milligramme scale, the solid fractions from steam-pretreated sweet sorghum bagasse (SSB) and triticale straw (TS) were subjected to homogenisation steps in sequential disintegrator and liquidiser at different severities prior to hand-sheet making (TAPPI). In the case of SSB, the disintegrator treatment (37,500 rpm) was sufficient to obtain the required fibre lengths, while the combined treatment with liquidiser (6250 rpm) and disintegrator (31,250 rpm) was needed for TS. The selected steps were able to improve homogenisation and fibre size distribution in the hand-sheets, attaining the required fibre lengths (less than 8 mm), with minimal influence on glucan conversion when using a conventional enzyme cocktail. The combined treatment and hand-sheet making had a more pronounced effect on the conversion of the xylan, with reduced xylose yields compared to small scale. The carbohydrate conversion in micro-assay was susceptible to more efficient enzyme combinations depending on the structural properties of the pretreated materials, presence and concentration of inhibitors as well as the enzyme dosage used. Nevertheless, the micro-assay method could distinguish between the different enzyme combinations, identifying those resulting in higher sugar yields from different lignocellulose materials pretreated under relatively mild conditions.
      PubDate: 2022-02-01
       
  • Enhancing enzymatic hydrolysis and fermentation efficiency of rice straw
           by pretreatment of sodium perborate

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      Abstract: In this study, we proposed a simple and effective sodium perborate (SPB) pretreatment method to enhance the enzymatic hydrolysis efficiency of rice straw (RS). The lignin removal rate reached 45.76% under the optimum pretreatment conditions of 8% SPB and 80 °C for 4 h, and the enzymatic hydrolysis efficiency of pretreated RS was 84% at a cellulase loading of 20 FPU/g RS. Through simultaneous saccharification and co-fermentation (SScF) of the pretreated RS solid with Saccharomyces cerevisiae SHY07-1, the maximum ethanol concentration was 15.29 g/L at 72 h, with a fermentation efficiency as high as 91.96%. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR) analyses revealed that the RS structure was destroyed by SPB pretreatment, and lignin was effectively removed. The overall data of this study indicate that SPB pretreatment is a promising method to improve enzymatic hydrolysis and bioethanol production from RS by inoculating Saccharomyces cerevisiae SHY07-1.
      PubDate: 2022-02-01
       
  • Methane production through anaerobic digestion of residual microalgal
           biomass after the extraction of valuable compounds

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      Abstract: Biorefinery concepts that combine several valorization pathways, including both bioproducts and bioenergy/biofuels, are of high interest in order to maximize the economic value of microalgal cultivation systems. In this study, the residual biomass obtained from the microalga Chlorella vulgaris following the chemical extraction of a valuable fraction consisting of either chlorophyll, proteins, or lipids was used as feedstock for biogas production in a laboratory-scale biochemical methane potential (BMP) assay performed in batch mode. The main aim of this study is to assess the effect of chemical extraction and removal of valuable fractions on the methane yield of residual microalgal biomass. The dry weight ratio of residual biomass to total biomass was 0.54 g/g after lipid extraction, 0.62 g/g after chlorophyll extraction, and 0.42 g/g after protein extraction. The methane yields of raw microalgae as well as residual microalgal biomass after lipid, chlorophyll, or protein extraction and removal were in the range 207–237 mL CH4/g volatile solids. Differences in the methane yields were not statistically significant. Hence, the recovery and removal of valuable compounds did not have a significant impact on the final methane yields of microalgal biomass by anaerobic digestion. Nevertheless, the methane production kinetics of residual microalgal biomass after lipid extraction displayed a diauxic pattern, possibly due to the inhibition of methanogenic bacteria by chloroform used as extraction solvent. This suggests that solvent toxicity must be considered when applying anaerobic digestion as a downstream process in biomass-based biorefineries.
      PubDate: 2022-02-01
       
  • Pretreatment methods of lignocellulosic wastes into value-added products:
           recent advances and possibilities

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      Abstract: A number of industries currently produce many tons of agroindustrial wastes with significant consequences on the environment and human and animal health. In recent years, increasing emphasis has been placed on reducing this negative impact. This review article aims to investigate the use of pretreatment methods that can be applied as an alternative to the usage of residual biomass. In addition, we seek to highlight the efficiency of the processes as well as possible weaknesses, which are associated with high energy and reagent consumption, low yields, and possible secondary impacts. Generally, the waste chemical composition consists mainly of cellulose, hemicellulose, and lignin; these can be fractionated, extracted, and purified to produce different value-added products, such as biofuels, organic acids, enzymes, biopolymers, and chemical additives. Despite the multiple possibilities to produce different products from lignocellulosic biomass, further research is still required to enhance the efficiency of the methods used nowadays and find new procedures. Graphical abstract Flowchart of pretreatment methods for lignocellulosic residues and some of the possible groups of products obtained with their processing.
      PubDate: 2022-02-01
       
 
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