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1.
World J Microbiol Biotechnol ; 36(3): 51, 2020 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-32157408

RESUMO

Culture-independent molecular-based approaches can be used to identify genes of interest from environmental sources that have desirable properties such as thermo activity. For this study, a putative thermo stable endoglucanase gene was identified from a mixed culture resulting from the inoculation of Brock-CMcellulose (1%) broth with mudspring water from Mt. Makiling, Laguna, Philippines that had been incubated at 90 °C. Genomic DNA was extracted from the cellulose-enriched mixed culture and endo1949 forward and reverse primers were used to amplify the endoglucanase gene, which was cloned into pCR-script plasmid vector. Blastn alignment of the sequenced insert revealed 99.69% similarity to the glycosyl hydrolase, sso1354 (CelA1; Q97YG7) from Saccharolobus solfataricus. The endoglucanase gene (GenBank accession number MK984682) was determined to be 1,021 nucleotide bases in length, corresponding to 333 amino acids with a molecular mass of ~ 37 kDa. The endoglucanase gene was inserted into a pET21 vector and transformed in E. coli BL21 for expression. Partially purified recombinant Mt. Makiling endoglucanase (MM-Engl) showed a specific activity of 187.61 U/mg and demonstrated heat stability up to 80 °C. The thermo-acid stable endoglucanase can be used in a supplementary hydrolysis step to further hydrolyze the lignocellulosic materials that were previously treated under high temperature-dilute acid conditions, thereby enhancing the release of more glucose sugars for bioethanol production.


Assuntos
Celulase/genética , Celulase/metabolismo , Celulose/metabolismo , DNA , Genômica , Água/metabolismo , Sequência de Aminoácidos , Archaea/enzimologia , Archaea/genética , Bactérias/enzimologia , Bactérias/genética , Sequência de Bases , Clonagem Molecular , Estabilidade Enzimática , Escherichia coli/genética , Concentração de Íons de Hidrogênio , Peso Molecular , Filipinas , Proteínas Recombinantes , Alinhamento de Sequência , Sulfolobales/enzimologia , Sulfolobales/genética , Temperatura Ambiente , Microbiologia da Água
2.
Bioresour Technol ; 304: 122848, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32113832

RESUMO

Lignocellulosic biomass is one of the most abundant organic resources worldwide and is a promising source of renewable energy and bioproducts. It basically consists of three fractions, cellulose, hemicelluloses and lignin, which confer a recalcitrant structure. As such, pretreatment steps are required to make each fraction available for further use, with acidic, alkaline and combined acidic-alkaline treatments being the most common techniques. This review focuses on recent strategies for lignocellulosic biomass pretreatment, with a critical discussion and comparison of their efficiency based on the composition of the materials. Mild pretreatments usually allow the recovery of the three biomass fractions for further transformation and valorisation. An insight is provided of newly developed technologies from recently filed patents on lignocellulosic biomass pretreatment and the transformation of agro-industrial residues into high value-added products, such as biofuels and organic acids.


Assuntos
Biocombustíveis , Lignina , Biomassa , Celulose , Hidrólise
3.
Bioresour Technol ; 304: 123064, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32115346

RESUMO

In this study, a novel psychrotrophic lignocelluloses degrading microbial consortium LTF-27 was successfully obtained from cold perennial forest soil by successive enrichment culture under facultative anaerobic static conditions. The microbial consortium showed efficient degradation of rice straw, which cellulose, hemicelluloses and lignin lost 71.7%, 65.6% and 12.5% of its weigh, respectively, in 20 days at 15 °C. The predominant liquid products were acetic acid and butyric acid during degrading lignocellulose in anaerobic digestion (AD) process inoculated with the LTF-27. The consortium mainly composed of Parabacteroides, Alcaligenes, Lysinibacillus, Sphingobacterium, and Clostridium, along with some unclassified uncultured bacteria, indicating powerful synergistic interaction in AD process. A multi-species lignocellulolytic enzyme system working cooperatingly on lignocelluolse degradation was revealed by proteomics analysis of cellulose bound fraction of the crude extracellular enzyme, which provides key theoretical base for further exploration and application of LTF-27.


Assuntos
Consórcios Microbianos , Oryza , Bactérias , Celulose , Lignina , Temperatura Ambiente
4.
Bioresour Technol ; 304: 123026, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32127244

RESUMO

The potential of low-cost bioenergy recovery from peanut shell was limited for its complex cellulose structure. In order to enhance the total reducing sugar (TRS) yield for bio-H2 production, peanut shell with heat (HT, 50-100 °C) or freezing pretreatment (FT, -80 to 0 °C) under different duration (0.5-12 h) was investigated. For uncovering the enhancement mechanisms, morphological feature and crystalline structure were analyzed by scanning electron microscope (SEM) and X-ray powder diffraction (XRD). The optimal pretreatment of 50 °C for 12 h was obtained with TRS yield increased 73.6%, while the H2 yield of 1.25 ml/mg-TRS was peaked with pretreatment at -80 °C. The SEM and XRD further demonstrated that mechanisms of HT and FT were realized through different ways, which were cracking and collapsing in HT, and delamination and peeling in FT, respectively.


Assuntos
Arachis , Celulose , Hidrólise , Temperatura Ambiente , Difração de Raios X
5.
Bioresour Technol ; 304: 122943, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32086033

RESUMO

An economically-prudent pretreatment is a crucial first step towards realization of the industrial lignocellulosic biorefinery. The aim of this study was to utilize lignocellulosic biomass to co-produce xylo-oligosaccharides (XOS) and glucose starting from a novel self-providing xylonic acid (XA) acidolysis method. Based on the optimization results of main acidolysis pretreatment parameters by uniform design experiments, we found that among various lignocellulosic materials, the highest yield of XOS from xylan was 54.16% with corncob, followed by 39.19% with wheat straw, 29.01% with corn straw and 30.23% with poplar sawdust. By effective degradation and removal of xylan constituents with XA acidolysis, enzymatic hydrolysabilities of inert cellulose constituents of corn cob, corn straw, wheat straw and poplar sawdust were achieved to 100%, 72.94%, 75.35% and 38.97%. Comparative mass balance diagrams of xylan and cellulose reveal that XA acidolysis pretreatment is environmental-friendly and effective for three agricultural residues, apart from woody poplar.


Assuntos
Celulose , Xilanos , Catálise , Hidrólise , Lignina , Xilose/análogos & derivados
6.
Bioresour Technol ; 303: 122888, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32028215

RESUMO

A novel mind-set, termed lignin-first biorefinery, is bewitching to synchronously boost lignin output for entirely lignocellulosic utilization. A lignin-first fractionation, using a food-additive derived ionic liquid (1-ethyl-3-methylimidazolium acesulfamate, emimAce) and mild alkaline pretreatments, was formed for the purposely isolating poplar lignin, whilst delivering a cellulose-rich substrate that can be easily available for enzymatic digestion. The emimAce-driven lignin, alkali-soluble lignin and hemicellulose, and accessible cellulose were sequentially gained. We introduce a lignin-first approach to extract the amorphous fractions, destroy the robust architecture, and reform cellulose-I to II, thereby advancing the cellulose bioconversion from 15.4 to 90.5%. A harvest of 70.7% lignin, 52.1% hemicellulose, and 330.1 mg/g glucose was fulfilled from raw poplar. A structural ''beginning-to-end'' analysis of lignin inferred that emimAce ions are expected to interact with lignin ß-aryl-ether due to their aromatic character. It was reasonable to derive benefits from lignin-first technique that can substantially augment the domain of biorefinering.


Assuntos
Líquidos Iônicos , Populus , Celulose , Hidrólise , Íons , Lignina
7.
Bioresour Technol ; 302: 122812, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32007848

RESUMO

In this work, two plant wastes were reused to fabricate the homogeneous 3D micro-nano porous structured humic acid/cellulose nanocomposite beads (IHA@CB) embedded with insoluble humic acid (IHA) particles. The subtle synthesis method attributed to the homogenous distribution of IHA particles in the cellulose matrix and improved the adsorption performance of IHA@CB for low concentration ciprofloxacin in water. Physical and chemical properties of the beads were characterized by SEM, EDX, XRD, FTIR, and the adsorption process of ciprofloxacin was studied by isotherm, kinetic and dynamic adsorption experiments. The maximum adsorption capacity of IHA@CB on CPX reached 10.87 mg g-1 under 318 K. The dynamic experiments were conducted by adjusting bed height, flow rate, initial concentration and pH values, and the regeneration experiments proved the adsorbent exhibited good repeatability. The adsorption mechanism was revealed that CPX was adsorbed by IHA@CB mainly through cation exchange.


Assuntos
Nanocompostos , Poluentes Químicos da Água , Adsorção , Celulose , Ciprofloxacino , Concentração de Íons de Hidrogênio , Cinética , Água
8.
Bioresour Technol ; 302: 122895, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32019706

RESUMO

Over the last century the pulp and paper sector has assessed various technologies to fractionate woody biomass to produce strong, bright fibers. Several of these processes have also been assessed for their potential to pretreat and fractionate biomass to enhance the subsequent enzymatic hydrolysis of the cellulosic component. Although many of these pretreatments are effective on agricultural residues, softwoods have proven more recalcitrant, primarily due to their high lignin content and structure. As delignification is too expensive to be used routinely a more economically attractive approach might be to alter the lignin. Recent work has shown that, using a modified chemithermomechanical pulping (CTMP) "front end", lignin can be modified and relocated. This significantly enhanced hemicellulose recovery and enzyme-mediated cellulose hydrolysis of woody biomass. As well as being effective on wood chips, the modified CTMP pretreatment process also enhanced the bioconversion of densified feedstocks such as pellets.


Assuntos
Lignina , Madeira , Biomassa , Celulose , Hidrólise
9.
Bioresour Technol ; 302: 122901, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32033842

RESUMO

The impact of lignin extracted from γ-valerolactone/water (GVL/H2O) pretreatment of corn stover on the enzymatic hydrolysis of cellulose was investigated. Two lignin samples were separated and named as GL25 and GL75 according to the amounts of sulfuric acid (25 mM and 75 mM) used in the GVL/H2O pretreatment. With the addition of 2 g/L of GL25 and GL75, the glucan conversion of enzymatic hydrolysis of Avicel improved markedly from 28.0% to 37.4% and 31.3%, respectively. Moreover, the improvement of glucan conversion increased when increasing the loadings of GL25 and GL75. A similar observation was made when GVL/H2O pretreated corn stover was the substrate. The results of the cellulase adsorption experiments showed that the GLs had a lower maximum cellulase adsorption capacity and binding strength compared to that of acid-insoluble lignin. Further structural characterization of the GLs revealed that they had a low zeta-potential and hydrophobicity, but a high Syringyl/Guaiacyl ratio.


Assuntos
Celulase , Lignina , Celulose , Hidrólise , Lactonas , Água , Zea mays
10.
J Environ Manage ; 255: 109906, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-32063302

RESUMO

Waste fruit peels which are usually discarded as agricultural wastes were utilized to isolate cellulose. The varied amount of isolated cellulose was used as sustainable support with hydrothermally synthesized molybdenum sulphide (MoS2) nano-petals via in-situ approach. The phase purity of all synthesized nanostructures was confirmed by PXRD whereas different oxidation states along with the interaction of cellulose with the MoS2 were examined by XPS analysis. In order to evaluate the performance of catalyst, the photodegradation rate was calculated for RhB dye as well as industrial effluent in visible light. The upgradation in photocatalytic competence was found significant by cellulose supported MoS2 nanostructures as compared to bare MoS2 nano-petals due to slow recombination of electron hole pairs. The maximum rate was pronounced by employing the cellulose at an amount of ~500 mg as a support due to existence of an optimal point where the delay in charge recombination reaches maximum.


Assuntos
Molibdênio , Nanoestruturas , Celulose , Dissulfetos , Frutas
11.
Bioresour Technol ; 299: 122632, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31889603

RESUMO

This study categorized different pretreatment methods into mild (below 120 °C), normal (120-200 °C) and extreme conditions (above 200 °C) for selective approach with efficient wood hydrolysis for direct market applications. The model two-step strategy of selective normal-hydrolysis: steam explosion (170 °C for 30 min) with concentrating normal-hydrolysis: organosolv at (160 °C for 20 min) on hard/softwood will delivery individual fractions of hemicellulose, lignin, and cellulose with recovery rate above 95%. The first step releases C5 sugars with a recovery rate of 80% followed by the second step for C6 sugars with 95% rate and direct use of reduced sugars into C5 and C6 value-added products. The categorized conditions will ease the selection of the pretreatment method for the wood type and model strategy will increase the hydrolysis rate with greater simplicity and validity. The integrated wood biorefinery with two-step treatment is an in-house and closed-loop with endless industrial applications.


Assuntos
Lignina , Madeira , Biomassa , Celulose , Hidrólise , Vapor
12.
Bioresour Technol ; 299: 122633, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31918972

RESUMO

The main objective of biomass pretreatment is to separate biomass components and provide easier access with ultimate aim for lignin removal, hemicellulose protection and cellulose crystallinity reduction. Effective bioconversion with least inhibitory compound production would play a considerable role in economic practicability of the process in order to achieve economic sustainability. In this regard, detoxification is an important condition to make biomass hydrolysate acquiescent to bioconversion; also, understanding of inhibitors effect on growth and fermentation are necessary requirements for system detoxification. A number of physical, chemical and biological methods like feedstock selection, membrane selection, neutralization, use of activated charcoal etc have been recommended and developed for removal or minimizing the inhibitory compounds effect. This work reviews various inhibitory compounds produced during pretreatment methods and their removal by various processes.


Assuntos
Celulose , Lignina , Biomassa , Fermentação , Hidrólise
13.
Bioresour Technol ; 299: 122695, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31918973

RESUMO

Lignocellulose-based processes for production of value-added products still face bottlenecks to attain feasibility. The key might lie on the biorefining of all lignocellulose main polymers, that is, cellulose, hemicellulose and lignin. Lignin, considered an impediment in the access of cellulose and normally considered for energy recovery purposes, can give a higher contribution towards profitability of lignocellulosic biorefineries. Organosolv pretreatment allows selective fractionation of lignocellulose into separate cellulose-, hemicellulose- and lignin-rich streams. Ethanol organosolv and wood substrates dominated the research studies, while a wide range of substrates need definition on the most suitable organosolv pretreatment systems. Techno-economic and environmental analyses of organosolv-based processes as well as proper valorization strategies of the hemicellulose-rich fraction are still scarce. In view of dominance of ethanol organosolv with high delignification yields and high-purity of the recovered cellulose-rich fractions, close R & D collaboration with 1st generation ethanol plants might boost commercialization.


Assuntos
Celulose , Lignina , Hidrólise , Madeira
14.
Bioresour Technol ; 300: 122700, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31918293

RESUMO

The objective of this study was to evaluate pyrolysis and co-pyrolysis behavior of cellulose and poly(methyl methacrylate) (PMMA) and examine the kinetics of the processes by using thermogravimetric analysis (TGA) coupled with FT-IR spectrometry. For this purpose, non-isothermal experiments were carried out using different heating rates and three prominent iso-conversional methods were used to obtain kinetic parameters at various extents of conversions from 0.1 to 0.9. Blending PMMA with cellulose had a marked effect on the process. The results of co-pyrolysis using a blending ratio of 50 wt% PMMA indicated that the highest rate of pyrolytic transformation was achieved at a conversion degree of 0.5 while activation energy ranged from 188.1 to 364.3 kJ/mol. The most intensive gas release during cellulose pyrolysis was CO2. Co-pyrolysis was more complicated than that of pyrolysis of cellulose and PMMA due to depolymerization and radical interactions.


Assuntos
Celulose , Polimetil Metacrilato , Cinética , Pirólise , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria
15.
AAPS PharmSciTech ; 21(2): 66, 2020 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-31932983

RESUMO

The purpose of this study was to investigate the potential of Bletilla striata polysaccharide (BSP, a natural glucomannan material) for the development of a gastroretentive drug delivery system for the first time. Novel BSP-based porous wafer was prepared for levofloxacin hydrochloride (LFH) delivery by combining floating, swelling, and mucoadhesion mechanisms. The influences of BSP and ethyl cellulose (EC) on drug release and mucoadhesive strength were studied by 32 factorial design. The optimized matrix was coated with polycaprolactone (PCL) electrospun membrane by electrospinning and heat treatment technology. The optimized formula (F6, coated) exhibited Q4 h of 41.20 ± 1.90%, Q8 h of 76.49 ± 1.69%, and mucoadhesive strength of 86.11 ± 1.33 gf, and its drug release profile most closely resembled the Korsmeyer-Peppas model with anomalous diffusion driving mechanism. F6 (coated) also presented excellent buoyancy, preferred swelling characteristic due to the porous structure formed by freeze-drying. Meanwhile, the internal morphology, physical state, drug-excipient compatibility, and thermal behavior were recorded. The negligible cytotoxicity of F6 (coated) was observed in human gastric epithelial cell cultures. In the in vitro antimicrobial experiment, the prepared wafer exhibited obvious bacterial inhibition zone, and due to its longer gastric retention, the wafer also performed a more effective Helicobacter pylori clearance than free LFH in vivo. Graphical abstract.


Assuntos
Sistemas de Liberação de Medicamentos , Mucosa Gástrica/metabolismo , Mananas/química , Orchidaceae/química , Poliésteres/química , Células Cultivadas , Celulose/análogos & derivados , Celulose/química , Composição de Medicamentos , Liberação Controlada de Fármacos , Humanos
16.
Bioresour Technol ; 301: 122725, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31958690

RESUMO

The inclusion of a pretreatment step in anaerobic digestion processes increases the digestibility of lignocellulosic biomass and enhances biogas yields by promoting lignin removal and the destruction of complex biomass structures. The increase in surface area enables the efficient interaction of microbes or enzymes, and a reduction in cellulose crystallinity improves the digestion process under anaerobic conditions. The pretreatment methods may vary based on the type of the lignocellulosic biomass, the nature of the subsequent process and the overall economics of the process. An improved biogas production by 1200% had been reported when ionic liquid used as pretreatment strategy for anaerobic digestion. The different pretreatment techniques used for lignocellulosic biomasses are generally grouped into physical, chemical, physicochemical, and biological methods. These four modes of pretreatment on lignocellulosic biomass and their impact on biogas production process is the major focus of this review article.


Assuntos
Biocombustíveis , Lignina , Biomassa , Celulose
17.
Bioresour Technol ; 299: 122685, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31918970

RESUMO

Different pretreatments strategies have been developed over the years mainly to enhance enzymatic cellulose degradation. In the new biorefinery era, a more holistic view on pretreatment is required to secure optimal use of the whole biomass. Hydrothermal pretreatment technology is regarded as very promising for lignocellulose biomass fractionation biorefinery and to be implemented at the industrial scale for biorefineries of second generation and circular bioeconomy, since it does not require no chemical inputs other than liquid water or steam and heat. This review focuses on the fundamentals of hydrothermal pretreatment, structure changes of biomass during this pretreatment, multiproduct strategies in terms of biorefinery, reactor technology and engineering aspects from batch to continuous operation. The treatise includes a case study of hydrothermal biomass pretreatment at pilot plant scale and integrated process design.


Assuntos
Lignina , Vapor , Biomassa , Celulose , Fracionamento Químico , Engenharia , Hidrólise
18.
Waste Manag ; 102: 281-303, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31704510

RESUMO

Nanocellulose has achieved an inimitable place and value in nano-materials research sector. Promising and exclusive physical, chemical and biological properties of nanocellulose make it an attractive and ideal material for various high end-user applications. Conventionally, the base material for nanocellulose i.e. cellulose is being extracted from various lignocellulosic raw materials (like wood, agro-industrial-residues, etc.) using pulping followed by bleaching sequences. As an alternate to lignocellulosic raw materials, waste paper also showed potential as a competent raw material due to its abundant availability and high cellulosic content (60-70%) with comparatively less hemicelluloses (10-20%) and lignin (5-10%) without any harsh treatments. The production yields of nanocellulose were reported to vary from 1.5% to 64% depending upon the waste papers and treatments given. The diameters of these nanocelluloses were reported in the range of 2-100 nm and crystallinity range around 54-95%. Thermal degradation of waste paper nanocellulose was varied from 187 °C to 371 °C. Although these properties are comparable with the nanocellulose obtained from lignocellulosic raw materials, yet waste paper is an underutilized source for nanocellulose preparation due to its ordinary fate of recycling, dumping and incineration. In the sight of necessity and possibility of waste paper utilization, this article reviews the outcomes of research carried out for preparation of nanocellulose using waste paper as a source of cellulose. There is a need of sincere investigation to convert this valuable waste to wealth i.e. waste papers to nanocellulose, which will be helpful in solid waste management to protect environment in economical way.


Assuntos
Celulose , Gerenciamento de Resíduos , Lignina , Resíduos Sólidos , Madeira
19.
Bioresour Technol ; 297: 122492, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31796376

RESUMO

In this study, the Mo-promoted Ir/SiO2 (Ir-MoOx/SiO2) catalysts combined with the zeolite HZSM-5 were used for the direct conversion of microcrystalline cellulose (MCC) to liquid fuel (C5/C6 alkanes) in n-dodecane/H2O system. A synergistic effect was formed between the partially reduced MoOx species and the Ir particles, which effectively promoted the catalytic activity of Ir/SiO2 catalyst. When the Mo/Ir molar ratio was 0.5, a high yield of C5/C6 alkanes (91.7%) was achieved at 210 â„ƒ for 12 h. In addition, the main component of C5/C6 alkanes was n-hexane, which was proven to be obtained by the hydrogenolysis of the key intermediate, sorbitol, formed from the hydrolysis and hydrogenation of MCC.


Assuntos
Alcanos , Dióxido de Silício , Catálise , Celulose , Hidrogenação
20.
Bioresour Technol ; 297: 122413, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31761628

RESUMO

MgO/N-doped active carbon (Mg/N-C) derived from sugarcane bagasse was prepared for the removal of methyl orange (MO). Mg/N-C composites presented the better adsorption capacity than that of active carbon and N-doped active carbon, of which the maximum adsorption capacity of 2-Mg/N-C-b2 for the MO removal is 384.61 mg g-1. The effects of MgO dosage, N-doped content, pyrolysis temperature, pH value, inorganic ions and solution temperature on the adsorption performance of Mg/N-C composites in the MO removal were investigated in detail. The pseudo-second order model and Langmuir isotherm model fitted well with the adsorption kinetics and isotherms of Mg/N-C. The rate-determining step was the boundary diffusion and intra-particle diffusion. The adsorption process of 2-Mg/N-C-b2 was a spontaneous and physisorption process.


Assuntos
Saccharum , Poluentes Químicos da Água , Adsorção , Carbono , Celulose , Concentração de Íons de Hidrogênio , Cinética , Óxido de Magnésio
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