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Schematic illustrations of co-current, counter-current, and flow-through pretreatment methods: (a) Co-current liquid hot water pretreatment, (b) counter-current reactor, (c) flow-through reactor.
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Context 1
... are three types of liquid hot water reactor con- figurations. Co-current, countercurrent, and flow through (illustrated in Fig. 4). In co-current pretreat- ments, a slurry of biomass and water is heated to the de- sired temperature and held at the pretreatment conditions for a controlled residence time before being cooled. Counter-current pretreatment is designed to move water and lignocellulose in opposite directions through the pretreatment reactor. In a ...
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... being used to pretreat corn fiber generated by corn-to-ethanol processing for the current fuel ethanol industry (Weil et al., 1998b, Beery et al., 2000Mosier et al., 2003a,b). Biomass liquid slurry of approximately 16% undissolved solids passes through heat exchangers, is heated to the desired temperature (140-180 °C), (heat exchangers 1 and 2, Fig. 4(a)) and held at temperature for 15-20 min as the slurry passes through an insulated plug-flow, snake-coil. The slurry is cooled and heat recovered by countercurrent heat exchange with the incoming slurry. The resulting pretreated fiber is devoid of starch, and the cellulose is completely digestible in 24 h at enzyme loadings of 20 ...
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... from low concentra- tion of sugars (of about 0.6-5.8 g/L) from hemicellulose. The solids that are left behind have enhanced digestibil- ity and a significant portion of the lignin is also re- moved. In countercurrent pretreatment the biomass slurry is passed in one direction while water is passed in another in a jacketed pretreatment reactor (Fig. 4(b)). Temperatures, back pressures and residence times are similar. In the flow-through pretreatment reactor water or acid is passed over a stationary bed, and re- moves some of the biomass components including lignin (Fig. ...
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... the biomass slurry is passed in one direction while water is passed in another in a jacketed pretreatment reactor (Fig. 4(b)). Temperatures, back pressures and residence times are similar. In the flow-through pretreatment reactor water or acid is passed over a stationary bed, and re- moves some of the biomass components including lignin (Fig. ...
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Citations
... Generally, biological pretreatment procedures move slowly. Additionally, some chemical and physical treatment methods are expensive (Mosier, 2005;Kaur et al., 2024), while eco-friendly pretreatments are occasionally ineffective Gadewar et al., 2023). Therefore, a substitute method for increasing cellulose concentration is to produce plants with either lower lignin levels or lignin compositions susceptible to chemical breakdown (Vanholme et al., 2010;Dixit et al., 2023;Chauhan et al., 2024). ...
Paddy straw, which is produced after the harvest of rice, is a major agricultural waste in the world. Rice straw has a high C:N ratio and is more resistant to microbial degradation than other straws because its main constituents are cellulose and hemicelluloses encrusted by lignin. When paddy straw is burned, hazardous substances such as CO2, CH4, CO, and NO are released into the air as smoke (less than ten micrometer-sized particles). The rise in the burning of paddy straw has contributed to too many accidents and health issues in the general population residing in Haryana, Punjab, and Uttar Pradesh. These states are being urged by the National Green Tribunal (NGT) to generate money instead of burning paddy straw. Even though these Lignocellulosic materials might be beneficial, not much has been done with them. This overview covers the properties of rice straw and husks, the numerous procedures used to create valuable products, and various applications that may be made for them. These include energy generation, environmental adsorbents, building supplies, and specialist commodities.
... Most pretreatment strategies, although effective at reducing recalcitrance, face challenges related to cost, operational robustness, Page 2 of 10 Bharadwaj et al. Biotechnology for Biofuels and Bioproducts (2024) 17:76 chemical recycle, and/or production of compounds that inhibit processing [7][8][9][10][11]. Processes that address these challenges are critical for greater use of lignocellulosic feedstocks in a range of biofuel and bioproduct processes. ...
Background
The aim of this study was to increase the accessibility and accelerate the breakdown of lignocellulosic biomass to methane in an anaerobic fermentation system by mechanical cotreatment: milling during fermentation, as an alternative to conventional pretreatment prior to biological deconstruction. Effluent from a mesophilic anaerobic digester running with unpretreated senescent switchgrass as the predominant carbon source was collected and subjected to ball milling for 0.5, 2, 5 and 10 min. Following this, a batch fermentation test was conducted with this material in triplicate for an additional 18 days with unmilled effluent as the ‘status quo’ control.
Results
The results indicate 0.5 – 10 min of cotreatment increased sugar solubilization by 5– 13% when compared to the unmilled control, with greater solubilization correlated with increased milling duration. Biogas concentrations ranged from 44% to 55.5% methane with the balance carbon dioxide. The total biogas production was statistically higher than the unmilled control for all treatments with 2 or more minutes of milling (α = 0.1). Cotreatment also decreased mean particle size. Energy consumption measurements of a lab-scale mill indicate that longer durations of milling offer diminishing benefits with respect to additional methane production.
Conclusions
Cotreatment in anaerobic digestion systems, as demonstrated in this study, provides an alternative approach to conventional pretreatments to increase biogas production from lignocellulosic grassy material.
... This approach involves applying saturated steam to biomass when it is under intense pressure. The components explode when the combination is held for a while to encourage hemicellulose hydrolysis [30,31]. Before the materials are exposed to air pressure, steam explosions are conducted at high pressures ranging from 0.2 to 5 MPa and temperatures between 160 and 260°. ...
Pennisetum purpureum is an easily cultivated fast-growing perennial grass with great potential as a bioenergy crop due to its high biomass production. Recent advancements in the processing of P. purpureum for the generation of bioethanol are highlighted in this review paper. Various pretreatment methods, namely, enzymatic, acid, and alkaline pretreatment have been investigated to enhance the efficiency of cellulose hydrolysis, which is a crucial step in bioethanol production. Moreover, genetic engineering approaches for enhancing the biomass yield and reducing the lignin are being discussed in this review. The production of bioethanol can be increased by several fermentation processes, including saccharification, separated hydrolysis, simultaneous saccharification, and fermentation. This comprehensive review explores recent advancements in bioethanol production, encompassing technological innovations, diversification of feedstock sources, genetic engineering methodologies, inventive pretreatment techniques, refinements in enzymatic hydrolysis, and enhancements in fermentation, ultimately highlighting the potential of P. purpureum as a sustainable bioethanol source while addressing the challenges and opportunities in its commercial-scale production.
... In addition, valuable chemicals such as ethanol, lactic acids, acetone, and butanol are obtained as final products of cellulose fermentation [3]. However, due to its physicochemical composition and structural features, lignocellulose is recalcitrant to biological conversion, resulting in a high cost for pretreatment and enzymatic hydrolysis [4][5][6][7]. Therefore, several studies have focused on the discovery of efficient and economically viable enzymes and microorganisms that can be exploited at an industrial scale to significantly lower the cost of lignocellulosic biomass conversions [7][8][9]. ...
Background
Ruminal microbial communities enriched on lignocellulosic biomass have shown considerable promise for the discovery of microorganisms and enzymes involved in digesting cell wall compounds, a key bottleneck in the development of second-generation biofuels and bioproducts, enabling a circular bioeconomy. Cardoon (Cynara cardunculus) is a promising inedible energy crop for current and future cellulosic biorefineries and the emerging bioenergy and bioproducts industries. The rumen microbiome can be considered an anaerobic “bioreactor”, where the resident microbiota carry out the depolymerization and hydrolysis of plant cell wall polysaccharides (PCWPs) through the catalytic action of fibrolytic enzymes. In this context, the rumen microbiota represents a potential source of microbes and fibrolytic enzymes suitable for biofuel production from feedstocks. In this study, metatranscriptomic and 16S rRNA sequencing were used to profile the microbiome and to investigate the genetic features within the microbial community adherent to the fiber fractions of the rumen content and to the residue of cardoon biomass incubated in the rumen of cannulated cows.
Results
The metatranscriptome of the cardoon and rumen fibre-adherent microbial communities were dissected in their functional and taxonomic components. From a functional point of view, transcripts involved in the methanogenesis from CO2 and H2, and from methanol were over-represented in the cardoon-adherent microbial community and were affiliated with the Methanobrevibacter and Methanosphaera of the Euryarchaeota phylum. Transcripts encoding glycoside hydrolases (GHs), carbohydrate-binding modules (CBMs), carbohydrate esterases (CEs), polysaccharide lyases (PLs), and glycoside transferases (GTs) accounted for 1.5% (6,957) of the total RNA coding transcripts and were taxonomically affiliated to major rumen fibrolytic microbes, such as Oscillospiraceae, Fibrobacteraceae, Neocallimastigaceae, Prevotellaceae, Lachnospiraceae, and Treponemataceae. The comparison of the expression profile between cardoon and rumen fiber-adherent microbial communities highlighted that specific fibrolytic enzymes were potentially responsible for the breakdown of cardoon PCWPs, which was driven by specific taxa, mainly Ruminococcus, Treponema, and Neocallimastigaceae.
Conclusions
Analysis of 16S rRNA and metatranscriptomic sequencing data revealed that the cow rumen microbiome harbors a repertoire of new enzymes capable of degrading PCWPs. Our results demonstrate the feasibility of using metatranscriptomics of enriched microbial RNA as a potential approach for accelerating the discovery of novel cellulolytic enzymes that could be harnessed for biotechnology. This research contributes a relevant perspective towards degrading cellulosic biomass and providing an economical route to the production of advanced biofuels and high-value bioproducts.
... Biochar, a carbon-rich residue, is used as a soil amendment or for carbon sequestration. Pyrolysis provides a sustainable method for turning textile waste into valuable energy products, aiding in waste management and renewable energy generation (Mosier et al., 2005). ...
Post-consumer garments (PCG) wastes pose a significant concern in the textile value chain, primarily due to their environmental impact. Over the last few decades, recycling of PCG has garnered substantial attention from textile industrialists and researchers. This manuscript provides a comprehensive review of the progress in recycling and reusing the PCG over the last 15 years. A bibliometric analysis is presented from Scopus data from 2010 to February 2024 using various statistical tools. The aim is to present the existing challenges and prospects of PCG, including increased demand for garments recycling, advanced recycling technologies, reusing, circular economy initiatives, socio-economic advantages, bioenergy production, stringent regulations, and new business opportunities. Cutting-edge recycling techniques are presented, including the pyrolysis of PCG waste to generate bio-oil and the fabrication of nanofibers from PCG for enhanced filtration and protective clothes. Additionally, the production of thermal-insulating high-performance cloth from PCG is mentioned. Challenges, such as contamination in medical textile waste, the complexity of recycling, lack of infrastructure, reduced economic viability, and declining end product quality, are addressed. Guidelines to tackle challenges include proper segregation, identification, and disinfection to overcome contamination issues. This article is a credible resource for textile industry experts, academicians, and engineers interested in promoting garment recycling to assist in accomplishing the sustainable development goals (SDGs).
... However, more severe pretreatment conditions also lead to more sugar degradation to inhibitory compounds, including furfural and 5-hydroxymethylfurfural (HMF). Choosing pretreatment conditions typically entails finding a balance between achieving a satisfactory sugar yield and minimizing the generation of degradation by-products [5,6]. In instances of inorganic acid pretreatment, such as sulfuric acid treatment, the process of neutralization leads to the creation of low-value waste streams called gypsum [3,4]. ...
Gluconic acid’s potential as a wheat straw pretreatment agent was studied at different concentrations (0.125–1 M) and temperatures (160–190 °C) for 30 min, followed by enzymatic hydrolysis. 0.125 M gluconic acid, 170 °C, yielded the highest xylose output, while 0.5 M gluconic acid at 190 °C yielded the best glucose yield. A fraction of gluconic acid decomposed during pretreatment. Detoxified hemicellulose hydrolysate from 0.125 M gluconate at 170 °C for 60 min showed promise for ethanol production. The gluconate contained in the detoxified hemicellulose hydrolysate can be fermented to ethanol along with other hemicellulose sugars present by Escherichia coli SL100. The ethanol yield from gluconate and sugars was about 90.4 ± 1.8%. The pretreated solids can be effectively converted to ethanol by Saccharomyces cerevisiae D5A via simultaneous saccharification and fermentation with the cellulase and β-glucosidase addition. The ethanol yield achieved was 92.8 ± 2.0% of the theoretical maximum. The cellulose conversion was about 70.8 ± 0.8%.
... Various pretreatments have been studied for lignocellulosic bioethanol production and biorefineries (da Costa Sousa et al., 2009;Mosier et al., 2005;Sun and Cheng, 2002). Among them, organosolv pretreatment is considered an effective pretreatment method for lignocellulosic biomass containing high lignin content to produce glucose, organosolv lignin, and other useful chemicals, because an organic solvent and an acid catalyst effectively break down internal lignin and hemicellulose bonds (Holtzapple and Humphrey, 1984). ...
... Enzymatic hydrolysis is a key process in integrated biorefineries, where enzymes are used to break down the pretreated lignocellulosic biomass into fermentable sugars [49]. This step is essential for converting the complex carbohydrates present in biomass, such as cellulose and hemicellulose, into simple sugars that can be fermented into biofuels, biochemicals, and other valuable products [54]. The process of enzyme hydrolysis in an integrated biorefinery typically involves the following steps: ...
Renewable and sustainable energy Book series aims to bring together leading academic scientists, researchers and research scholars to publish their experiences and research results on all aspects of Renewable and sustainable energy. It also provides a premier interdisciplinary platform for researchers, practitioners and educators to present and discuss the most recent innovations, trends, and concerns as well as practical challenges encountered and solutions adopted in the specified fields. High quality research contributions describing original and unpublished results of conceptual, constructive, empirical, experimental, or theoretical work in all areas of Renewable and sustainable energy are cordially invited for publication
... It can be classified into several different types based on their production methods, feedstocks requirements, potential applications and properties. Continued research and development efforts are focused on advancing biofuel technologies (11), exploring new feedstocks, and improving their sustainability and efficiency. Worldwide reported different types of biofuels that are commonly used are as follows: ...
... It is the most widely produced biofuel globally. Cellulosic bioethanol is produced from the lignocellulosic components of plant biomass, utilizing enzymes or other technologies to break down complex carbohydrates into simple sugars (11). It is commonly used as a fuel additive and can be used in flexible-fuel vehicles. ...
... Advanced biofuels refer to a category of biofuels that are produced from non-food feedstocks and employ advanced technologies to convert biomass into liquid or gaseous fuels. These biofuels are designed to offer improved environmental performance, energy efficiency, and compatibility with existing engines and infrastructure (11). The development and deployment of advanced biofuels are driven by the need to reduce greenhouse gas emissions, promote energy security, and diversify the fuel mix. ...
Biotechnology is one of the emerging fields that can add new and better application in a wide range of sectors like health care, service sector, agriculture, and processing industry to name some. This book will provide an excellent opportunity to focus on recent developments in the frontier areas of Biotechnology and establish new collaborations in these areas. The book will highlight multidisciplinary perspectives to interested biotechnologists, microbiologists, pharmaceutical experts, bioprocess engineers, agronomists, medical professionals, sustainability researchers and academicians. This technical publication will provide a platform for potential knowledge exhibition on recent trends, theories and practices in the field of Biotechnology.
... the secondly Along with a drawback as bacteriophage is easily liable to grow here will shut down entire bioreactors possibly. In this phase, it may primarily react to limit the concentration of iso butanol due to this process cell not being able to tolerate and sensitivity must be diminished insignificant amount with utilizing mutagenesis and selected mutant may be able to less effected with bacteriophage and enhance the total yield with this precaution for isobutanol or bio-butanol (33).Bacillus subtilis B. subtilis, gram-positive, rod-shaped microbes produce lingo-cellulosic based isobutanol and are also efficiently measured with metabolic pathway standard hereditary practices (34).Bacillus subtilis could concentrate to advanced or higher yields of isobutanol being produced with modification (35). (38). ...
Renewable and sustainable energy Book series aims to bring together leading academic scientists, researchers and research scholars to publish their experiences and research results on all aspects of Renewable and sustainable energy. It also provides a premier interdisciplinary platform for researchers, practitioners and educators to present and discuss the most recent innovations, trends, and concerns as well as practical challenges encountered and solutions adopted in the specified fields. High quality research contributions describing original and unpublished results of conceptual, constructive, empirical, experimental, or theoretical work in all areas of Renewable and sustainable energy are cordially invited for publication.
