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1.
Bioresour Technol ; 393: 129953, 2024 Feb.
Article in English | MEDLINE | ID: mdl-37914053

ABSTRACT

The biochemical methane potential test is a standard method to determine the biodegradability of lignocellulosic wastes (LWs) during anaerobic digestion (AD) with disadvantages of long experiment duration and high operating expense. This paper developed a machine learning model to predict the cumulative methane yield (CMY) using the data of 157 LWs regarding physicochemical characteristics, digestion condition and methane yield, with the coefficient of determination equal to 0.869. Model interpretability analyses underscored lignin content, organic loading, and nitrogen content as pivotal attributes for CMY prediction. For the feedstocks with a cellulose content exceeding about 50%, the CMY in the early AD stage would be relatively lower than those with low cellulose content, but prolonging digestion time could promote methane production. Besides, lignin content in feedstock surpassing 15% would significantly inhibit methane production. This work contributes to valuable guidance for feedstock selection and operation optimization for AD plants.


Subject(s)
Cellulose , Lignin , Lignin/chemistry , Anaerobiosis , Biomass , Methane , Biofuels
2.
Bioresour Technol ; 393: 130092, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38000644

ABSTRACT

Tobacco straw is an abundant biomass in China's agricultural ecosystems, and has high potential for methane production. However, the anaerobic digestion (AD) efficiency is limited by the recalcitrant lignocellulose structure of the tobacco straw. In this study, three microaerobic pretreatments were performed for the AD of tobacco straw to increase methane production. Among them, microbial pretreatment with biogas slurry at an oxygen concentration of 4 mL/g VS resulted in the highest methane production of 349.1 mL/g VS, increasing by 19.8 % than that of untreated. During this pretreatment, the relative abundances of Enterococcus and Clostridium sensu stricto 12, which are closely related to acetic acid production and cellulose degradation, were high, and these bacteria might have an important contribution to substrate hydrolysis and the methanogenesis efficiency of the AD process. This study advances the understanding of microaerobic pretreatment processes and provides technological guidance for the efficient utilization of tobacco straw.


Subject(s)
Ecosystem , Methane , Anaerobiosis , Zea mays/metabolism , Bacteria/metabolism , Biofuels
3.
Environ Sci Pollut Res Int ; 31(1): 1079-1093, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38030843

ABSTRACT

Anaerobic digestion (AD) technology is a practical approach to alleviate severe environmental issues caused by vegetable wastes (VWs). However, its primary product is methane-rich biogas converted from the precursors (mainly volatile fatty acids, VFAs) after long fermentation periods, making traditional AD projects of low economic profits. Intervening in the methanogenesis stage artificially to produce high value-added VFAs can shorten the reaction time of the AD process and significantly improve profits, posing a promising alternative for treating VWs. Given this, this study applied heat shock (HS) pretreatment to inoculum to prevent methane production during AD and systemically investigated the effects of HS pretreatment and initial pH regulation on VFA production from VWs. The results showed that appropriate HS pretreatment effectively inhibited methane generation but promoted VFA accumulation, and VFA production was further enhanced by adjusting the initial pH to 8.0 and 9.0. The highest total VFA concentration of 14,883 mg/L with a VFA yield of 496.1 mg/gVS, 26.98% higher than that of the untreated group, was achieved at an initial pH 8.0 with HS pretreatment of 80 °C for 1 h. Moreover, pH regulation influenced the metabolic pathway of VFA production from VWs during AD, as butyrate was the dominant product at an initial pH of 6.0, while the increased initial pH improved the acetate proportion.


Subject(s)
Bioreactors , Vegetables , Vegetables/metabolism , Anaerobiosis , Hydrogen-Ion Concentration , Fermentation , Fatty Acids, Volatile/metabolism , Methane/metabolism , Heat-Shock Response , Sewage
4.
Sci Total Environ ; 873: 162324, 2023 May 15.
Article in English | MEDLINE | ID: mdl-36813202

ABSTRACT

Biodegradable plastics (BPs) tend to replace conventional plastics, which increases the amount of BP waste entering the environment. The anaerobic environment exists extensively in nature, and anaerobic digestion has become a widely used technique for organic waste treatment. Many kinds of BPs have low biodegradability (BD) and biodegradation rates under anaerobic condition due to the limitation of hydrolysis, so they still have harmful environmental consequences in anaerobic environment. There is an urgent need to find an intervention method to improve the biodegradation of BPs. Therefore, this study aimed to investigate the effectiveness of alkaline pretreatment in accelerating the thermophilic anaerobic degradation of ten widely used BPs, such as poly (lactic acid) (PLA), poly (butylene adipate-co-terephthalate) (PBAT), thermoplastic starch (TPS), poly (butylene succinate-co-butylene adipate) (PBSA), cellulose diacetate (CDA), etc. The results showed that NaOH pretreatment significantly improved the solubility of PBSA, PLA, poly (propylene carbonate) (PPC), and TPS. Except for PBAT, pretreatment with an appropriate NaOH concentration could improve the BD and degradation rate. The pretreatment also reduced the lag phase in the anaerobic degradation of BPs such as PLA, PPC, and TPS. Specifically, for CDA and PBSA, the BD increased from 4.6 % and 30.5 % to 85.2 % and 88.7 %, with increments of 1752.2 % and 190.8 %, respectively. Microbial analysis indicated that NaOH pretreatment promoted the dissolution and hydrolysis of PBSA and PLA and the deacetylation of CDA, which contributed to rapid and complete degradation. This work not only provides a promising method for improving the degradation of BP waste but also lays the foundation for its large-scale application and safe disposal.


Subject(s)
Biodegradable Plastics , Anaerobiosis , Sodium Hydroxide , Polyesters , Plastics/metabolism , Biodegradation, Environmental , Adipates/metabolism
5.
J Basic Microbiol ; 63(2): 128-139, 2023 Feb.
Article in English | MEDLINE | ID: mdl-36192143

ABSTRACT

A promising strategy to alleviate the plastic pollution from traditional petroleum-based plastics is the application of biodegradable plastics, in which polyhydroxyalkanoates (PHAs) have received increasing interest owing to their considerable biodegradability. In the PHAs family, poly(3-hydroxybutyrate-co-3-hydroxvalerate) (PHBV) has better mechanical properties, which possesses broader application prospects. With this purpose, the present study adopted Cupriavidus necator to synthesize PHBV utilizing volatile fatty acids (VFAs) as sole carbon sources. Results showed that the concentration and composition of VFAs significantly influenced the production of PHAs. Especially, even carbon VFAs (acetate and butyrate) synthesized only poly(3-hydroxybutyrate) (PHB), while the addition of odd carbon VFAs (propionate and valerate) resulted in PHBV production. The 3-hydroxyvalerate (3HV) contents in PHBV were directly determined by the specific VFAs compositions, in which valerate was the preferred substrate for 3HV accumulation. After optimization by response surface methodology, the highest PHBV accumulation achieved 79.47% in dry cells, and the conversion efficiency of VFAs to PHBV reached 40%, with the PHBV production of 1.20 ± 0.05 g/L. This study revealed the metabolic rule of VFAs converting into PHAs by C. necator and figured out the optimal VFAs condition for PHBV accumulation, which provides a valuable reference for developing downstream strategies of PHBV production in industrial applications in future.


Subject(s)
Cupriavidus necator , Polyhydroxyalkanoates , Cupriavidus necator/genetics , 3-Hydroxybutyric Acid , Fatty Acids, Volatile , Plastics , Carbon
6.
Waste Manag ; 151: 154-162, 2022 Sep.
Article in English | MEDLINE | ID: mdl-35952413

ABSTRACT

The dramatic increase of textile wastes has become a major global concern, which calls for alternative practices to alleviate severe environmental pollution and waste of resources due to their improper disposal and management. Anaerobic digestion (AD) is a cost-effective and eco-friendly technology that allows the bioconversion of organic wastes into clean energy (methane), which might be potentially useful for recycling textile wastes. In this study, AD was applied to 11 commonly available textile wastes in daily life to explore their feasibility, along with the methane production efficiency, biodegradability (BD), degradation mechanism, and microbial community dynamics during AD. The results showed that all textile wastes presented an obvious decomposition from an integrated shape to fragmented pieces within 18 days except blue denim. The highest experimental methane production (EMP) of 356.0 mL/g volatile solids (VS) and BD of 78.0 % were obtained with flax. The degradation mechanism could be concluded that predominant bacteria, especially Clostridium sensu stricto, first attached to the surface of textile waste and converted its main compositions cellulose and hemicellulose into acetate as the core intermediate. Then, acetate was utilized by the major methanogen, Methanothrix, through the acetoclastic methanogenesis pathway to produce methane. This study not only enriches the understanding of textile wastes degradation mechanisms during AD and provides very useful data on methane production from commonly available textile wastes but also proposes a promising method for efficiently recycling and utilizing the diverse range of textile wastes to reduce waste pollution and generate clean energy simultaneously.


Subject(s)
Methane , Microbiota , Anaerobiosis , Bioreactors , Recycling , Textiles
7.
Environ Sci Pollut Res Int ; 29(56): 85433-85443, 2022 Dec.
Article in English | MEDLINE | ID: mdl-35794328

ABSTRACT

A large amount of eggplant stalk (ES) is incinerated after harvesting of eggplant every year, which aggravates environmental pollution and waste of resources. Converting ES into methane through anaerobic digestion (AD) technology may be a potential treatment method, considering the low environmental impact and high energy recovery. Firstly, this study explored the effects of organic loading (OL) and feed to inoculum ratio (F/I ratio) on the AD of ES by response surface methodology (RSM). In order to achieve higher AD efficiency, various pretreatments (acid, alkali, alkaline hydrogen peroxide (AHP), microwave, and ultrasound) were introduced and comprehensively assessed with regard to methane production, organic matter destruction, and kinetic parameters. Results showed that OL had a more significant impact on AD process compared to F/I ratio and methane production was enhanced remarkably when the OL and F/I ratio were 35.0 g VS/L and 3.0, respectively. XRD, FTIR, and SEM analyses of pretreated ES showed that alkali and AHP pretreatments performed better in delignification. Under optimal conditions, the ES pretreated with 1.5% AHP (adjusted by KOH) performed the maximum methane production of 262.2 mL/g VS with a biodegradability of 95.0%, which increased by 334.1% compared to untreated ES. This paper not only provides the theoretical data about methane production performance of ES but also gives practical guidance for efficient utilization of similar vegetable stalk biowastes, which is also promising for large-scale industrial applications in the future.


Subject(s)
Solanum melongena , Anaerobiosis , Methane , Kinetics , Alkalies , Biofuels , Bioreactors
8.
Comput Intell Neurosci ; 2022: 1493137, 2022.
Article in English | MEDLINE | ID: mdl-35855804

ABSTRACT

Objectives: The Traditional Chinese Medicine (TCM) formula Yi-Fei-Jian-Pi-Tang (YFJPT) has been demonstrated effective against Corona Virus Disease 2019 (Covid-19). The aim of this article is to make a thorough inquiry about its active constituent as well as mechanisms against Covid-19 via TCM network pharmacology. Methods: All the ingredients of YFJPT are obtained from the pharmacology database of the TCM system. The genes which are associated with the targets are obtained by utilizing UniProt. The herb-target network is built up by utilizing Cytoscape. The target protein-protein interaction network is built by utilizing the STRING database and Cytoscape. The critical targets of YFJPT are explored by Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG). Results: The outcomes show that YFJPT might has 33 therapeutic targets on Covid-19, namely, interleukin 2 (IL2), heme oxygenase 1 (HMOX1), interleukin 4 (IL4), interferon gamma (FNG), α nuclear factor of kappa light polypeptide gene enhancer in Bcells inhibitor, alpha (NFKBIA), nuclear factor-k-gene binding (NFKB), nitric oxide synthase 3 (NOS3), intercellular adhesion molecule 1 (ICAM1), hypoxia inducible factor 1 subunit alpha (HIF1A), mitogen-activated protein kinase 3 (MAPK3), epidermal growth factor receptor (EGFR), interleukin 10 (IL10), jun proto-oncogene (JUN), C-C motif chemokine ligand 2 (CCL2), C-X-C motif chemokine ligand 8 (CXCL8), tumor protein p53 (TP53), interleukin 1 beta (IL1B), AKT serine/threonine kinase 1 (AKT1), tumor necrosis factor (TNF), interleukin 6 (IL6), erb-b2 receptor tyrosine kinase 2 (ERBB2), RELA proto-oncogene (RELA), NF-κB subunit, caspase 8 (CASP8), peroxisome proliferator activated receptor alpha (PPARA), TIMP metallopeptidase inhibitor 1 (TIMP1), transforming growth factor beta 1 (TGFB1), interleukin 1 alpha (IL1A), signal transducer and activator of transcription 1 (STAT1), mitogen-activated protein kinase 8 (MAPK8), myeloperoxidase (MPO), matrix metallopeptidase 3 (MMP3), matrix metallopeptidase 1 (MMP1), and NFE2 like bZIP transcription factor 2 (NFE2L2). The gene enrichment analysis prompts that YFJPT most likely contributes to patients related to Covid-19 by regulating the pathways of cancers. Conclusions: That will lay a foundation for the clinical rational application and further experimental research of YFJPT.


Subject(s)
COVID-19 , Chemokines , Humans , Ligands , Metalloproteases , Network Pharmacology
9.
Environ Sci Pollut Res Int ; 29(59): 88507-88518, 2022 Dec.
Article in English | MEDLINE | ID: mdl-35834077

ABSTRACT

Copious amounts of cucumber vine (CV) derived from crop growing and harvesting are casually discarded in the field, posing severely negative impacts on public health and the ecological environment. Treating CV via anaerobic digestion (AD) could represent a promising approach while the recalcitrant lignocellulosic structure restricts its conversion efficiency, thus underscoring the importance of valid pretreatments. This study systematically investigated the effects of nine types of commonly applied chemical pretreatments involved H2SO4, HCl, H3PO4, NaOH, KOH, Ca(OH)2, CaO, H2O2, and alkaline hydrogen peroxide (AHP) pretreatments on methane production of CV. Results showed that alkaline and AHP pretreatments were beneficial to the methane production of CV and obtained the considerable cumulative methane yield and biodegradability of 194.3-241.5 mL·gVS-1 and 47.59-59.15%, respectively, 36.83-70.07% higher than untreated. Analyses of lignocellulosic compositions and structural characterizations revealed that alkaline and AHP pretreatments well destroyed both hemicellulose and lignin, which commendably increased the accessibility of cellulose, facilitating the methane production. The findings of this study provide not only efficient pretreatment methods for the disposal and utilization of CV during AD process but also promising alternatives for enhancing methane production performance of similar vine residues, which would be greatly valuable for industrial applications in the future.


Subject(s)
Cucumis sativus , Anaerobiosis , Cucumis sativus/metabolism , Hydrogen Peroxide , Methane , Lignin/chemistry , Biofuels
10.
Sheng Wu Gong Cheng Xue Bao ; 38(5): 1784-1808, 2022 May 25.
Article in Chinese | MEDLINE | ID: mdl-35611729

ABSTRACT

With the continuously increasing demands of plastic products in the current society, the challenge of disposing plastic waste is constantly increasing, leading to the urgent need of mitigating plastic pollution. As a consequence, much attention has been paid to biodegradable plastics due to their degradability in a bio-active environment under certain conditions. Biodegradable plastics herald vast development potentials and considerable market prospects. The degradation of numerous types of biodegradable plastics will be affected by many factors. A thorough understanding of degradation mechanisms as well as functional microbial strains and enzymes is the key to comprehensive utilization and efficient treatment and disposal of biodegradable plastics. The article summarized the types, properties, advantages and disadvantages, and main applications of common biodegradable plastics. The degradation mechanisms, functional microbial strains and enzymes, as well as the degradation degree and duration under different environmental conditions, were also summarized. This review may help better understand the degradation of biodegradable plastics wastes.


Subject(s)
Biodegradable Plastics , Biodegradation, Environmental
11.
Sci Total Environ ; 834: 155167, 2022 Aug 15.
Article in English | MEDLINE | ID: mdl-35421475

ABSTRACT

The serious environmental problem caused by traditional plastics has stimulated the popularization of biodegradable plastics (BPs). However, the rigorous prerequisite for the efficient degradation of BPs has not eliminated its potential hazard to nature. In most biosystems exists the anaerobic environment, but it is still controversial whether BPs can be degraded under such condition. Therefore, this study systematically assessed the anaerobic degradation performance of ten common BPs under mesophilic and thermophilic conditions. Results showed that four BPs were degraded evidently under mesophilic condition with the biodegradability of 57.9%-84.6%, while during thermophilic condition, five BPs showed remarkable degradation performance with the biodegradability of 53.0% to 95.7%. According to morphological and micro-structural analysis, the biodegradation of the BPs probably proceeded via bulk and/or surface erosion. Under mesophilic condition, Anaerolineales, Bacteroidales, Clostridiales, SBR1031, and Synergistales appeared to play an important role. During thermophilic condition, the hydrolysis, acidogenesis, and methanogenesis of most BPs were mainly conducted by Coprothermobacter and the archaea Methanothermobacter. This work not only provides crucial data on the anaerobic biodigestibility of BPs but also enriches the understanding of the BPs degradation mechanisms, which are of great importance for future popularization of BP products and simultaneously relieving the environmental pollution.


Subject(s)
Biodegradable Plastics , Microbiota , Anaerobiosis , Bacteria, Anaerobic/metabolism , Biodegradation, Environmental , Bioreactors , Methane/metabolism , Plastics/metabolism , Temperature
12.
Sci Total Environ ; 830: 154864, 2022 Jul 15.
Article in English | MEDLINE | ID: mdl-35351511

ABSTRACT

The application of high-strength steels in marine engineering is gaining importance because of their high performance and ability to help save resources. However, detailed and systematic information about the corrosion behavior of high-strength steels in different marine corrosion zones is still limited. This study aimed to investigate and compare the corrosion behavior of AISI 4135 high-strength steel in marine atmospheric, splash, tidal, and immersion zones, focusing on rust layer characteristics, corrosion form and electrochemical corrosion behavior. Corrosion exposure experiments were performed in a specific sea area, and the recovered steel samples were characterized by Raman spectroscopy, confocal laser scanning microscopy, nitrogen adsorption analysis, etc. Results showed that the rust layer formed on the surface of the steel in all corrosion zones had component delamination. The steel samples in the atmospheric, splash, and tidal zones were characterized by pitting corrosion, where the average depths of the corrosion pits were 56.1 ± 4.7 µm, 199.5 ± 12.6 µm, 108.1 ± 11.0 µm, respectively, whereas those in the immersion zone were characterized by general corrosion. Meanwhile, electrochemical tests were performed on the electrode samples during exposure. Results showed that the corrosion of the steel progressed from slow to fast in the atmospheric, splash, and tidal zones, whereas it was relatively steady in the immersion zone. Differentiated models of the corrosion evolution of steel under wet-dry cycle and immersion conditions were presented. This discrepancy is related to the varying degrees of accumulation of ionic corrosion products at the metal/oxide interface, which are determined by the mean pore access diameter of the rust layer and the corrosion environment. This study is highly significant for the design of marine engineering considering the safety applications of high-strength steel structures in harsh marine environments.


Subject(s)
Steel , Corrosion
13.
Bioresour Technol ; 343: 126032, 2022 Jan.
Article in English | MEDLINE | ID: mdl-34592450

ABSTRACT

With growing popularity of durian and jackfruit, environment threats following improper management of durian shell (DS) and jackfruit peel (JP) are increasingly serious. Anaerobic digestion is a potential solution but concern on its unsatisfied efficiency from lignocellulosic recalcitrance remains. This work applied four representative pretreatments on DS and JP to determine the effects on methane generation, energy potential, and environmental benefits. The suitable pretreatments for DS and JP were 3% KOH and 5% AHP, causing 103.8% and 69.8% increase in methane yield and biodegradability than untreated, respectively. Moreover, 3% KOH-treated DS and 5% AHP-treated JP could potentially produce total energy of 2.0 × 109 MJ/year, reduce coal consumption by 6.8 × 104 ton/year, and cut emission by 2.2 × 1010 particulate/year, which might alleviate the serious energy crisis and environmental issues from the overuse of fossil fuel. This study provides important insights into efficient use of DS and JP, and a reference for other fruit wastes.


Subject(s)
Artocarpus , Bombacaceae , Anaerobiosis , Biofuels , Methane
14.
Environ Sci Pollut Res Int ; 28(38): 54177-54186, 2021 Oct.
Article in English | MEDLINE | ID: mdl-34402020

ABSTRACT

With the development of agriculture, a huge amount of vegetable waste (VW) is produced every year, posing a large considerable environmental problem that cannot be ignored. Anaerobic digestion (AD), as an eco-friendly, efficient, and sustainable biomass conversion technology, may be used to address the pollution caused by VW. The compositional components of various VWs are different, which will affect their biomethane potential and directly determine whether they are suitable substrates for AD. Thus, this study involved a systematic analysis of the composition and biomethane potential of 20 typical VWs. The results showed that the methane yields of the VWs were different (207.5-346.3 mL/g VS) owing to the differences in composition. More importantly, a correlation between the contents of organic components and methane production was established, and then used to predict methane production by VW rapidly. In addition, first-order model, modified Gompertz, and Cone models were used to describe the biochemical methanogenesis mechanism of these VWs. The results of this study can provide a reference for fundamental research on the AD of VW as well as serve a convenient and precise method to predict methane production by different VWs through analyzing compositional components, which will be beneficial for pollution prevention and the comprehensive utilization of VW in the future.


Subject(s)
Bioreactors , Vegetables , Anaerobiosis , Biofuels , Biomass , Methane
15.
Front Microbiol ; 12: 688290, 2021.
Article in English | MEDLINE | ID: mdl-34295321

ABSTRACT

Having been generated with a tremendous amount annually, paper waste (PW) represents a large proportion in municipal solid waste (MSW) and also a potential source of renewable energy production through the application of anaerobic digestion (AD). However, the recalcitrant lignocellulosic structure poses obstacles to efficient utilization in this way. Recently, anaerobic and microaerobic pretreatment have attracted attention as approaches to overcome the obstacles of biogas production. This study was set out to present a systematic comparison and assessment of anaerobic and microaerobic pretreatment of PW with different oxygen loadings by five microbial agents: composting inoculum (CI), straw-decomposing inoculum (SI), cow manure (CM), sheep manure (SM), and digestate effluent (DE). The hints of microbial community evolution during the pretreatment and AD were tracked by 16S rRNA high-throughput sequencing. The results demonstrated that PW pretreated by DE with an oxygen loading of 15 ml/gVS showed the highest cumulative methane yield (CMY) of 343.2 ml/gVS, with a BD of 79.3%. In addition to DE, SI and SM were also regarded as outstanding microbial agents for pretreatment because of the acceleration of methane production at the early stage of AD. The microbial community analysis showed that Clostridium sensu stricto 1 and Clostridium sensu stricto 10 possessed high relative abundance after anaerobic pretreatment by SI, while Bacteroides and Macellibacteroides were enriched after microaerobic pretreatment by SM, which were all contributable to the cellulose degradation. Besides, aerobic Bacillus in SI and Acinetobacter in SM and DE probably promoted lignin degradation only under microaerobic conditions. During AD, VadinBC27, Ruminococcaceae Incertae Sedis, Clostridium sensu stricto 1, Fastidiosipila, and Caldicoprobacter were the crucial bacteria that facilitated the biodegradation of PW. By comparing the groups with same microbial agent, it could be found that changing the oxygen loading might result in the alternation between hydrogenotrophic and acetoclastic methanogens, which possibly affected the methanogenesis stage. This study not only devised a promising tactic for making full use of PW but also provided a greater understanding of the evolution of microbial community in the pretreatment and AD processes, targeting the efficient utilization of lignocellulosic biomass in full-scale applications.

16.
Bioresour Technol ; 337: 125456, 2021 Oct.
Article in English | MEDLINE | ID: mdl-34320740

ABSTRACT

Microbial pretreatment to lignocellulosic biomass for anaerobic digestion (AD) has achieved increased attention; however, the low efficiency and unclear mechanism of oxygen parameter affecting this process performance limit its practical application. In this study, five readily available microbial consortia were developed to analyze the influences of various oxygen concentrations during pretreatment process upon methane conversion efficiency and microbiota within AD of giant grass. Results found that anaerobic pretreatment by liquid or straw composting inoculant, along with microaerobic pretreatment by cow manure at 10 mL/g VS oxygen concentration, obtained 23.1%, 24.4%, and 16.0% higher methane yields (275.3, 279.8, and 265.3 mL/g VS) than corresponding untreated group, respectively. Microbial community analyses showed that microbial responses to oxygen varied significantly with microbial consortium, which consequently caused different AD performances. The findings will enrich theoretical knowledge of microbial pretreatment and provide a technological guidance for efficient utilization of giant grass and other lignocellulosic biomasses.


Subject(s)
Biofuels , Poaceae , Anaerobiosis , Animals , Cattle , Female , Manure , Methane
17.
Environ Sci Pollut Res Int ; 26(24): 25084-25091, 2019 Aug.
Article in English | MEDLINE | ID: mdl-31254197

ABSTRACT

Anaerobic digestion (AD) is one of the best technologies for producing methane from biomass wastes with limited environmental impacts. Most AD plants need a continuous and stable supply of feedstock for their sustained operation for which lignocellulosic biomass can be effectively utilized. Switchgrass (SG), also known as Panicum virgatum, is a tall-growing grass which exists throughout the year in areas with warm climate and has the potential to produce biomethane. The present work investigated anaerobic digestion performance of SG while focusing on enhancing the methane yield by employing central composite design of response surface methodology (RSM). The aim of this research was to find out the best level of factors including feed-to-inoculum (F/I) ratio, organic loading (OL), and pH for optimizing the desired output of biomethane production from 3% KOH-pretreated SG. Results revealed that the highest value of experimental methane yield was 288.4 mL/gVS at the optimal F/I ratio, pH, and OL of 1, 6.96, and 24 gVS/L, respectively. Moreover, 3% KOH pretreatment improved the biodegradability of SG significantly from 14.23 to 85.53%. This study forms the basis for future application of SG for enhanced methane production.


Subject(s)
Methane/biosynthesis , Panicum/chemistry , Anaerobiosis , Biodegradation, Environmental , Biomass
18.
J Sep Sci ; 38(15): 2588-96, 2015 Aug.
Article in English | MEDLINE | ID: mdl-25964189

ABSTRACT

St. John's wort has attracted particular attention because of its beneficial effects as an antidepressant, antiviral, and anticancer agent. A method for the combination of integrated expanded bed adsorption chromatography and countercurrent chromatography for the simultaneous extraction and purification of pseudohypericin and hypericin from the herb is presented in this paper. Firstly, the constituents were extracted and directly adsorbed by expanded bed adsorption chromatography under optimal conditions. The stepwise elution was then performed by expanded bed adsorption chromatography that enriched the targets with higher purities and recoveries compared to other methods. Secondly, the eluent fractions from expanded bed adsorption chromatography were further separated by two-step high-speed countercurrent chromatography. A two-step high-speed countercurrent chromatography method with a biphasic solvent system composed of n-hexane/ethyl acetate/methanol/water with a volume ratio of 1:2:1:2 was performed by stepwise changing the flow rate of the mobile phase. Consequently, 5.6 mg of pseudohypericin and 2.2 mg of hypericin with purities of 95.5 and 95.0%, respectively, were successfully obtained from 40 mg of crude sample.

19.
J Chromatogr A ; 1378: 58-64, 2015 Jan 23.
Article in English | MEDLINE | ID: mdl-25573189

ABSTRACT

Separation of polar alkaloids by countercurrent chromatography (CCC) is challengeable due to their close partition behaviors in solvent system. In this paper, a two-stage method for isolation of epiberberine, jatrorrhizine, palmatine, coptisine, and berberine from Rhizoma coptidis was presented. The first stage separation performed on CCC was based on the principle of reactive extraction. Trifluoroacetic acid was acted as a modulator to selectively react with alkaloids, which changed their partition coefficients in solvent system. Purified epiberberine and other partially separated targets were eluted by ammonium adjusted mobile phase. In the second stage, four alkaloids were purified in pH-zone-refining CCC mode. All the targets collected were over 97% pure determined by HPLC. The method developed demonstrates performing of reactive extraction on standard CCC as an option for separation of polar alkaloids from medicinal plants.


Subject(s)
Alkaloids/isolation & purification , Chemical Fractionation/methods , Countercurrent Distribution , Plants, Medicinal/chemistry , Ranunculaceae/chemistry , Alkaloids/chemistry , Berberine/analogs & derivatives , Berberine/isolation & purification , Berberine Alkaloids/isolation & purification , Drugs, Chinese Herbal/isolation & purification
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