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Mitigation of global warming, energy security and industrial competitiveness urge the energy-intensive pulp and paper industry (PPI) to transform energy use practices. This study investigates how the PPI has responded to the need for the energy transition in the 2000s. Finland and Sweden as forerunners of energy-efficient operation and decarbonization of the PPI are used as target countries. Understanding of changes in energy consumption is complemented using decomposition analysis (Logarithmic Mean Divisia Index Method) and the energy efficiency index approach. Analysis of companies’ investments in energy technologies is used for explaining changes in energy production. Evidence of significant development towards the more sustainable operation of the PPI was found. Energy consumption per produced unit has decreased, i.e., energy efficiency has improved. Fossil fuels have been partially replaced with bio-based alternatives. Thus, the CO2 intensity has decreased substantially. The generation of renewable electricity has increased in both countries. Examples of Finland and Sweden indicate that the PPI has great potential to contribute to CO2 emission reduction worldwide in the future as energy efficiency can be further improved, and the share of fossil fuels can be decreased increasing the use of biofuels and self-generated green electricity at least in kraft pulp mills.

The utilization of paper on a commercial scale is increasing day by day throughout the world that produces million of tons of paper waste yearly and burdened for landfills. The present study focuses on the exploitation of waste papers (office paper, newspaper and tissue paper) as a cheapest alternative source of energy to extract fermentable sugar by applying chemical and enzymatic pretreatments. The quantification of released sugar was analyzed by spectrophotometer and high performance liquid chromatography refractive index (HPLC-RI) detector. Cellulose (12 FPU/g) and β-glucosidase (12 FPU/g) was found to be effective for the extraction of fermentable sugar from paper waste. The contents of cellulose (C6H10O5)n, hemicellulose (C5H10O5)n and lignin (C9H10O2,C10H12O3,C11H14O4) found in office paper were 40%, 32.5%, 22.5%, in newspaper 46.5%, 30.5% 22.5%, and in tissue paper 62%, 22%, 15.5%, respectively. The percentages of sugar contents assessed in this study were 62% in tissue paper and 46.5% in newspaper and 40% in office papers. Among the three substrates, tissue paper (23.4 mg/mL) released a significant amount of glucose (C6H6O12), whereas newspaper (20.8 mg/mL) and office paper (19.6 mg/mL) released less amount of sugar. This research of acid pre-treatment and enzymatic hydrolysis was an efficient method to improve glucose conversion from lignocellulosic waste. Furthermore, this approach can be proved the first step towards the sustainable production of bioethanol from wastepaper-extracted sugar.

Paper and pulp mills generate substantial quantities of cellulose-rich sludge materials that are disposed in landfills at a large scale. For sustainability purposes, sludge materials can be bioprocessed to produce renewable fuels and useful chemicals. The enzymatic hydrolysis of cellulose is the process bottleneck that affects the conversion economics directly by using zero-cost raw materials. In order to study and optimize the process, the characteristics of the sludge raw materials should be first evaluated. In this work, sludge samples were obtained from paper mills located at different locations in Wisconsin and Minnesota. Part of the sludge samples was washed (de-ashed) with hydrochloric acid while the other part remained unwashed. The samples were subjected to multiple spectroscopic analyses techniques to evaluate the morphological properties of cellulose fibers and to estimate the total structural carbohydrate content. The results showed that the de-ashing process changed some fiber characteristics and cellulose crystallinity structure in all sludge samples. Sludge sample A (obtained from Kraft pulp and recycled paper mill region) showed a high percentage of fiber, with crystalline cellulose, compared to the other two sludge samples suggesting that sludge A is a valuable source to make value-added products. Aspen Plus mass and energy calculations performed in view of the ‘zero’ cost and the reliable supply of sludge raw materials producing 2 mol H2/mol glucose. Moreover, the results showed that extracting crystalline cellulose from these sludge samples is more profitable than crystalline cellulose made from the other lignocellulosic feedstocks. The results reported here showed that the utilization of these sludge materials would be an economically attractive and promising alternative for the production of hydrogen.

Paper mulberry, a fast-growing and vigorous plant, is a potential substrate for producing lignocellulosic bioethanol and an important renewable alternative to fossil fuels. In order to improve the economic feasibility of ethanol production from paper mulberry, H3PO4/H2O2 pretreatment was selected as the most suitable pretreatment method that could produce the highest glucose concentration (131 g/L) compared with other pretreatments (73.2–89.3 g/L) at high solid loading. Whereafter, the final solid loading of H3PO4/H2O2 pretreatment was significantly increased to 40% (w/v) without any decrease in the final glucose concentration. Finally, a novel Fed-nonisothermal-simultaneous saccharification and fermentation was constructed using H3PO4/H2O2 pretreated paper mulberry, which bypassed the inhibition caused by paper mulberry solid and high temperature on the traditional simultaneous saccharification and fermentation, improving ethanol concentration (63.9 g/L), ethanol productivity (1.33 g/L/h) and ethanol yield (0.160 g/g-biomass) by 30.4%, 30.4% and 30.1%, respectively, compared to those obtained from SSF (simultaneous saccharification and fermentation) process. Thus, we have opened up a novel way to produce ethanol or other biofuels using the paper mulberry as an outstanding alternative substrate.

By way of broadening the use of diverse sustainable bioethanol feedstocks, the potentials of Paper mulberry fruit juice (PMFJ), as a non-food, sugar-based substrate, were evaluated for fuel ethanol production. The suitability of PMFJ was proven, as maximum ethanol concentration (56.4 g/L) and yield (0.39 g/g) were achieved within half a day of the start of fermentation, corresponding to very high ethanol productivity of 4.7 g/L/hr. The established potentials were further optimally maximized through the response surface methodology (RSM). At the optimal temperature of 30 °C, yeast concentration of 0.55 g/L, and pH of 5, ethanol concentration, productivity, and yield obtained were 73.69 g/L, 4.61 g/L/hr, and 0.48 g/g, respectively. Under these ideal conditions, diverse metal salts were afterward screened for their effects on PMFJ fermentation. Based on a two-level fractional factorial design, nutrient addition had no positive impact on ethanol production. Thus, under the optimal process conditions, and without any external nutrient supplementation, bioethanol from PMFJ compared favorably with typical sugar-based energy crops, highlighting its resourcefulness as a high-value biomass resource for fuel ethanol production. Graphical Abstract

Paper waste is a raw material for a lot of products with different added value. The engineering, economic and environmental aspects of paper waste recycling are analysed for production of composite material, cellulose nanofibers and nanocrystals, bricks with paper components, porous carbon, film of biopolymer, enzymatic sugar and bioenergy: bioethanol, hydrogen and biofuel. Through multicriteria analysis, it was possible to determine the most feasible paper waste recycling product in case of four product groups: egg packaging boxes, cardboard, reused paper, cellulose nanomaterials (nanofibers and nanocrystals). The production of cellulose nanofibres and cellulose nanocrystals has an advantage over egg packaging and cardboard production as well as reusable paper.

Bioethanol production using paper wastes seems a promising approach towards sustainable energy, but mainly hindered by hazardous ink. Therefore, in our experimental plan various methods were applied for the deinking of waste newspapers, laser printed papers and examination papers. A newly designed paper pulper reduced the pulping time from 6 h to 2 h. Cellulase (15 FPU/g) from Aspergillus oryzae MDU-4 was found effective for the deinking of newspapers, whereas laccase isozymes (150 U/g) from Ganoderma lucidum MDU-7 along with 2 mM HOBt was preferred for the ink removal and degradation from the examination papers. Ozonation in the presence of Tween-80 was found to be efficient in the removal of toxic toners used in laser printing papers. The biologically and physically deinked papers, studied with the help of SEM, TEM, FTIR, and XRD analysis revealed significant changes in the chemical and surface structure. Moreover, the saccharification of deinked papers with the help of an enzymatic consortium of Trichoderma citrinoviride MDU-1 resulted in 305 mg/g, 377 mg/g, and 409 mg/g release of sugars from the newspaper, examination paper, and laser printed paper, respectively. Finally, the enzymatic hydrolysates fermented with Saccharomyces cerevisiae NCIM-3640 produced 3.35 g/L ethanol, with 40.85% ethanol yield.

Paper sludge is a solid waste by-product abundantly produced in the paper industry and contains fine minerals and lignocellulosic biomass. In this contribution, the ex-situ catalytic fast pyrolysis of paper sludge with a high mineral content of ca. 71 wt% is reported for the first time and demonstrated in a pilot-scale unit (feeding rate of 11.3 kg h−1) using a granular Na2CO3/γ-Al2O3 catalyst (loading of 650 g) to produce a high-grade bio-oil at a fast pyrolysis temperature of 475 ± 5 °C (pre-screened using a pyroprobe) and a catalytic upgrading temperature of 500 °C. Besides, > 99 wt% minerals in the paper sludge could be recovered, including paper fillers such as CaCO3 (major) and talc. The bio-oil obtained at a carbon yield of 21 C.% has a low oxygen content of 3.2 wt%, a low total acidity number of 5.2 mg KOH g−1, low H2O content of 0.7 wt%, and a high higher heating value of 40.9 MJ kg−1. It consists of value-added bio-based chemicals such as paraffins, olefins, and low molecular weight aromatics. The results demonstrate that the use of paper sludge to recover minerals and to obtain fuels and chemicals using ex-situ catalytic pyrolysis is technically feasible at a pilot plant scale, which will be of importance for the development of future bio-based economy.

Waste-to-energy or value-added products have been increasingly considered in many pulp and paper mills (PPMs) worldwide. However, developing appropriate conversion technologies is a major challenge in transforming PPMs wastes into biofuels or value-added biomaterials. In the present study, a long-term (320 d) anaerobic digestion of primary sludge of a thermomechanical pulp mill (TMP) was carried out for the first time in a thermophilic anaerobic membrane bioreactor (ThAnMBR). Effect of organic loading rate (OLR) in the range of 2.5–6.8 kg-COD/m3 d and hydraulic retention times (HRT) of 3–8 d on the process performance was investigated. Under various OLRs, stable biogas productions were obtained, and the best results were achieved with lower OLR (2.5 kg-COD/m3 d) and higher HRT (8 d), at biogas yields of 189 L biogas/kg MLSS fed. However, it was found that biogas production and sludge biomass degradation decrease when the organic loading rate increases. The proportion of sludge reduction ranged from 28.9 to 46.7% depending on the applied OLRs. Despite varying OLRs, stable membrane performance was obtained, where the required membrane flux was easily maintained during the reactor operation. In this study, also the properties of digestate and membrane permeates were studied under different operating conditions, and they fluctuated to some extent with OLR. ThAnMBR is a promising new technology for pulp and paper mill primary sludge treatment.

The dramatic fluctuations of oil cost and climate change have together concentrated political and scientific attention on the search of alternative fuels. The aim of this work is to recycle waste p...

Brazil is currently focused on its energy matrix transition in favor of increasing of the share of renewable energy carriers for both enhanced energy security and mitigation of greenhouse gas emissions. In this context, the country`s pulp and paper industry whose different wastes teams are not generally exploited, could play a critical role. Accordingly, the main objective of this work is to develop a conceptual ‘systemic’ biorefinery framework integrating the treatment of pulp and paper mill wastewater using upflow anaerobic sludge blanket (UASB) reactor with energy recovery through biogas production and its conversion into heat and power in stationary engines and boilers, respectively. Based on the results obtained through the present case study, it was revealed that the adoption of UASB reactors by the paper mill industry could properly addresses the environmental concerns faced while could contribute to the national agenda favoring an increasing share of renewable energies in the country`s energy matrix. The financial analysis showed that the investment required for the implementation of UASB reactors within a biorefinery platform would be minor vs. the investment in the whole mill and would be returned in 6.4 yr with a high return on investment even when operated at half of operational capacity. Moreover, through the developed UASB reactor-based biorefinery, the Brazilian pulp and paper industry as a whole could avoid 1.06 ×105 CO2eq tons, effectively contributing to the decarbonization of the country`s economy.

Aims: The aim of the present study is to produce ethanol from waste paper and spent mushroom using Saccharomyces cerevisiae as enzymes for the fermentation process. Study Design: Waste paper and spent mushroom samples were subjected to fermentation and hydrolysis by Aspergilus niger and Saccharomyces cerevisiae to produce bioethanol. Place and Duration of Study: This study was carried out in the Environmental Microbiology Laboratory, University of Port Harcourt, Nigeria, between May and October 2017. Methodology: Waste paper and spent mushrooms samples were hydrolyzed by Aspergillus niger, and the hydrolysate from each set up subjected to fermentation by Saccharomyces cerevisiae. Ethanol was extracted by fractional distillation, and qualitatively determined by Gas Chromatography with Mass Spectrometry. Results: After 8 days of fermentation, there was decrease in glucose content in waste paper hydrolysate ranging from (0.51-0.1 mg/l), and spent mushroom substrate (0.3-0.07 mg/l). Upon extraction of the bioethanol, the highest yield was recorded for waste paper hydrolysate which after characterization with GC-MS ethanol concentration was 28.01 mg/l, followed by spent mushroom hydrolysate 26.8 mg/l. Conclusion: This study revealed that bioethanol can be obtained from fermentation of waste paper using Saccharomyces cerevisiae and ethanol can be obtained after the paper has been used in growing edible mushroom; if adopted, this could be a way to achieving environmental sustainability.

Ample interest for more efficient utilization of bio-based residues has emerged in the Nordic pulp and paper (P&P) industry, which uses virgin wood as feedstock. Although different bioenergy retrofit technologies for production of liquid, solid, and gaseous bioenergy products have been applied in the existing P&P mills, the number of installations remains small. The lack of profound knowledge of existing bioenergy retrofits hinders the replication and market uptake of potential technologies. This review synthesises the existing knowledge of European installations and identifies the key drivers and barriers for implementation to foster the market uptake of potential technologies. The bioenergy retrofits were reviewed in terms of technical maturity, drivers, barriers and market potential. Based on this evaluation, common drivers and barriers towards wider market uptake were outlined from political, economic, social, technical, environmental, and legal perspective. Technologies already commercially applied include anaerobic fermentation of sludge, bark gasification, tall oil diesel and bioethanol production, whereas lignin extraction, biomethanol production, hydrothermal liquefaction and hydrothermal carbonization are being demonstrated or first applications are under construction. The findings of this review show that a stable flow of residues at P&P mills creates a solid base for retrofitting. New innovative bio-based products would allow widening the companies' product portfolios and creating new businesses. Also, European Union's (EU) legislation drives towards advanced biofuels production. Wider uptake of the retrofitting technologies requires overcoming the barriers related to uncertainty of economic feasibility and unestablished markets for new products rather than technical immaturity.

A new process for the production of bioethanol from paper mill sludge (PMS) is described in this work. PMS biomass feedstock was processed via the simultaneous saccharification and fermentation (SSF) with and without accelerants. The enzymatic hydrolysis and fermentation were first evaluated, and the energy demand was 2.2 MJ/L of produced ethanol. When the enzymatic hydrolysis and fermentation were combined, the energy demand was reduced to 1.0 MJ/L ethanol, the sugars production increased, and the overall capital cost of the process decreased. The sugar yield was improved by adding accelerant and selecting the optimal fiber recovery method. The accelerant improved the enzymatic hydrolysis via a pathing/bridging mechanism. The SSF with the chemical fiber recovery method coupled with accelerant addition would be the best process configuration. Upon this combination, the glucose profile was enhanced from 9.8 g/L to 17.0 g/L. The sludge fiber conversion by SSF was improved by selecting an efficient fiber recovery method combined with the accelerant addition. SSF in chemical fiber recovery with accelerant addition was the best process by a 10% improvement of ethanol yield. The proposed process configuration offers a lower cost and sustainable process and contributes to the circular economy of zero waste discharges.

This study considered the possibility of reducing the environmental footprint of paper and pulp industry by producing bioenergy from paper sludge by using process wastewater instead of fresh water, and reclaiming water trapped in paper sludge. Experimental studies are conducted with streams from three different pulp and paper mills (virgin pulp mill (VP), corrugated recycling mill (CR), tissue printed recycling mill (TPR)) for sequential bioethanol and biogas production with simultaneous reclamation of water from paper sludge (PS). Total energy yields of 9215, 6387, 5278 MJ/tonne dry PS for VP, CR and TPR, respectively, were obtained for ethanol-biogas production. Virgin pulp paper sludge gave the highest yield for ethanol and biogas in stand-alone processes (275.4 kg and 67.7 kg per ton dry PS respectively) and also highest energy conversion efficiency (55%) in sequential process compared with CR and TPR. Energy and environmental case study conducted on virgin pulp mill has proven the possibility of using paper sludge bioenergy to reduce energy demand by 10%, while reclaiming 82% of the water from the PS, reducing greenhouse gas emissions (GHG) by 3 times and producing solids suitable for land spreading.

Today, the continue depletion of fossil sources represents one of the main problems and European Union has incremented the amount of renewable fraction inside automotive fuels obtained from lignocellulosic biomasses. In this work, the production of the advanced biofuel n-butyl levulinate (BL) from Arundo donax L. and industrial paper waste powder has been investigated. In particular, the direct acid-catalysed alcoholysis employing n-butanol as solvent/reagent and H2SO4 as homogeneous catalyst in the presence of microwave and traditional heatings has been optimized. With both the investigated biomasses, BL yields around 30 mol% have been achieved with high loadings of feedstock, 20 and 14 wt% for Arundo donax L. and paper waste powder, respectively, at 190 °C after 15 min, adopting microwave heating and H2SO4 loading of 1.2 wt%. Moreover, the employment of traditional heating has allowed us to achieve BL yields about 30 mol% with the low catalyst loadings of 0.6 and 0.4 wt% for Arundo donax L. and paper waste powder, respectively, at 200°C after 3h, adopting the same biomass loadings (20 and 14 wt%). Finally, a preliminary study of diesel engine performances and emissions regarding the potential application of the obtained mixture as additive for diesel fuel was successfully performed., Proceedings of the 28th European Biomass Conference and Exhibition, 6-9 July 2020, Virtual, pp. 559-566

This study presents 5-hydroxymethylfurfural removal from waste hand paper hydrolysate using activated carbon adsorption. In this context, the effects of adsorbent dosage, initial 5-hydroxymethylfurfural concentration, temperature, and agitation speed on 5-hydroxymethylfurfural adsorption were investigated. Moreover, isotherm and kinetic evaluations were performed using Langmuir, Freundlich, and Temkin models. The experimental data were correlated with zero, first, pseudo-first, and Weber–Morris intraparticle diffusion models. The toxicity of 5-hydroxymethylfurfural was determined using the resazurin reduction assay, and the EC50 of 5-hydroxymethylfurfural in the hydrolysate was found as 192 mg/L. Most convenient 5-hydroxymethylfurfural adsorption was obtained at 5 g/L AC dosage, 40 °C and 150 rpm agitation speed. The highest 5-hydroxymethylfurfural removal efficiency was 92% at 7 g/L AC dosage. The adsorption data fitted best with the Langmuir isotherm model with a maximum uptake capacity of 70.92 mg/g (R2: 0.96). The zero-order reaction kinetic model was the most suitable one among the others inspected. It was determined that intraparticle diffusion was not the rate-limiting step. This study showed that waste hand paper hydrolysate can effectively be detoxified by activated carbon adsorption. © 2019, Islamic Azad University (IAU).

Black liquor (spent cooking liquor) is one of the major byproducts of pulp and paper manufacturing. Black liquor contains 10–50% lignin, which is the main organic matter found within that liquor. Different types of black liquors are obtained as per the type of feedstock, pulping process and cooking method adopted by industries. In recent years, industries have been required to accommodate newer varieties of feedstock such as non-wood and recycled fibers during the delignification process, which can save plenty of trees and hence reduce their carbon footprint. Therefore, the newer black liquors being generated differ in their physical characteristics, chemical composition, and energy content from that of traditional processes.Currently, black liquor is seen as a platform for the production of many renewable materials for industrial applications that can be environmentally friendly with the potential to be used substitute for fuel and commercial materials. However, most of the published review articles focus on the kraft spent liquor and its derived kraft lignin that is obtained from kraft pulping process at the pulp and paper as a source of bio-fuel and biomaterials. Meanwhile, several other black liquors such as soda, and neutral sulfite spent (NSSC) liquor and their derived lignin are not highlighted as sources of biofuel and biomaterials. Therefore, this review highlights all the types of black liquors including soda, and neutral sulfite spent (NSSC) liquor in terms of their sources, physical and chemical characterization, purification processes, and the potential applications of black liquor and its derived lignin.

Health and environmental impacts of fossil fuel utilization have urged the need to find alternative bioresources that could act as renewable source of energy called as biofuels. Bioethanol is currently the most produced biofuel. First-generation feedstocks result in food–fuel competition; hence, second-generation feedstocks are mostly preferred, which consist of lignocellulosic biomass, but they have a costly and difficult pre-treatment techniques that will add up to the total cost of the production of bioethanol. Pulp and paper industry is one among the fast-growing industries which simultaneously generates large amount of residues which are disposed in landfills. These residues are wastes from paper making that is rich in monosaccharides or even polysaccharides besides lignin and hence can be used as a proper feedstock for bioethanol production which requires lesser pre-treatment. It acts as zero or negative feedstock cost and has the potential for the production of cellulosic ethanol. The aim is to cover the recent developments and key challenges for the successful introduction of paper mill sludge in the bioethanol production industry. The covered subjects are sustainability of biofuel, paper-making process, Indian scenario of paper mills, and environmental impacts of paper mill sludge along with the pre-treatments employed on paper mill sludge for bioethanol production.

International audience; The hemp plant Cannabis sativa Linn, referring to industrial hemp, is a high-yielding annual industrial crop grown providing fibers from hemp stalk and oil from hemp seeds. Although hemp is a niche crop, hemp production is currently undergoing a renaissance. More than 30 countries grow hemp, with China being the largest hemp producing and exporting country. Europe and Canada are also important actors in the global hemp market. Traditionally, hemp as a fiber plant has been used for the production of apparels, fabrics, papers, cordages and building materials. The hurds, as waste by-product of fiber production, were used for bedding of animals, the seeds for human nutrition, e.g., as flour, and the oil for a wide range of purposes, from cooking to cosmetics. Hemp has also been an important crop throughout human history for medicine. Other more recent applications include materials for insulation and furniture, automotive composites for interior applications and motor vehicle parts, bioplastics, jewelry and fashion sectors, animal feed, animal bedding, and energy and fuel production. Foods containing hemp seed and oil are currently marketed worldwide for both animal and human nutrition. They also find applications in beverages and in neutraceutical products. Hemp oil is also used for cosmetics and personal care items, paints, printing inks, detergents and solvents. It is estimated that the global market for hemp consists of more than 25,000 products. Currently, the construction and insulation sector, paper and textile industries, and food and nutrition domains are the main markets while the cosmetics and automotive sector are growing markets. Innovative applications, e.g., in the medical and therapeutic domains, cosmeceuticals, phytoremediation, acoustic domain, wastewater treatment, biofuels, biopesticides and biotechnology, open new challenges. Hemp is also the object of numerous fundamental studies. This review presents and discusses the traditional and new uses of industrial hemp.

The effect of various pretreatments for efficient hydrolysis of waste office paper and newspaper into fermentable sugars and subsequent production of bioethanol through fermentation was investigated. Pretreatment with H2O2 (0.5% v/v) at 121 °C for 30 min was considered as the most effective method for this kind of soft biomass like waste paper due to the considerable increase in available cellulose and sugar yield in addition to efficient delignification. Under optimized conditions, enzymatic hydrolysis of pretreated office paper and newspaper resulted the sugar yield of 24.5 and 13.26 g/L with hydrolysis efficiency of 91.8 and 79.6%, respectively. Further, ethanol production using the hydrolysate by Saccharomyces cerevisiae was about 11.15 and 6.65 g/L with the productivity of 0.32 and 0.28 (g ethanol/L/h), respectively. The improved yields achieved through the pretreatment and subsequent ethanol production suggested that the waste paper could be a potential feedstock for the production of bioethanol.

The present study investigates the effect on methane production from waste paper when co-digested with macroalgal biomass. Both feedstocks were previously mechanically pretreated to reduce their particle size. The study was planned according two factors: the feedstock to inoculum (F/I) ratio and the waste paper to macroalgae (WP/MA) ratio. The F/I ratios checked were 0.2, 0.3 and 0.4 and the WP/MA ratios were 0:100, 25:75, 50:50, 75:25 and 100:0. The highest methane yield (386 L kg−1 VSadded) was achieved at an F/I ratio of 0.2 and a WP/MA ratio of 50:50. A biodegradability index of 0.87 obtained in this study indicates complete conversion of feedstock at an optimum C/N ratio of 26. Synergistic effect was found for WP/MA 25:75, 50:50 and 75:25 mixing ratios compared with the substrates mono-digestion.

Background: In spite of the continuous efforts and investments in the last decades, lignocellulosic ethanol is still not economically competitive with fossil fuels. Optimization is still required in different parts of the process. Namely, the cost effective usage of enzymes has been pursued by different strategies, one of them being recycling. Results: Cellulase recycling was analyzed on Recycled Paper Sludge (RPS) conversion into bioethanol under intensified conditions. Different cocktails were studied regarding thermostability, hydrolysis efficiency, distribution in the multiphasic system and recovery from solid. Celluclast showed inferior stability at higher temperatures (45-55 ºC), nevertheless its performance at moderate temperatures (40ºC) was slightly superior to other cocktails (ACCELLERASE®1500 and Cellic®CTec2). Celluclast distribution in the solid-liquid medium was also more favorable, enabling to recover 88 % of final activity at the end of the process. A Central Composite Design studied the influence of solids concentration and enzyme dosage on RPS conversion by Celluclast. Solids concentration showed a significant positive effect on glucose production, no major limitations being found from utilizing high amounts of solids under the studied conditions. Increasing enzyme loading from 20 to 30 FPU/ gcellulose had no significant effect on sugars production, suggesting that 22 % solids and 20 FPU/gcellulose are the best operational conditions towards an intensified process. Applying these, a system of multiple rounds of hydrolysis with enzyme recycling was implemented, allowing to maintain steady levels of enzyme activity with only 50 % of enzyme on each recycling stage. Additionally, interesting levels of solid conversion (70-81 %) were also achieved, leading to considerable improvements on glucose and ethanol production comparatively with the reports available so far (3.4 and 3.8 fold, respectively). Conclusions: Enzyme recycling viability depends on enzyme distribution between the solid and liquid phases at the end of hydrolysis, as well as enzymes thermostability. Both are critical features to be observed for a judicious choice of enzyme cocktail. This work demonstrates that enzyme recycling in intensified biomass degradation can be achieved through simple means. The process is possibly much more effective at larger scale, hence novel enzyme formulations favoring this possibility should be developed for industrial usage., This work had the fnancial support of the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/ BIO/04469/2013 unit, COMPETE 2020 (POCI-01-0145-FEDER-006684) and the MultiBiorefnery project (POCI-01-0145-FEDER-016403). Furthermore, FCT equally supported the Ph.D. grant to DG (SFRH/BD/88623/2012)., info:eu-repo/semantics/publishedVersion

The present work establishes the cost-effective and miniature microfluidic self-pumping paper based enzymatic biofuel cell (P-EBFC). The developed Y-shaped P-EBFC consists of buckeye composite multiwall carbon nanotube (MWCNT) buckypaper (BP) based bio-anode and bio-cathode that were immobilized with electro-biocatalytic enzymes glucose oxidase (GOx) and laccase, respectively. The electrocatalytic activity of enzymes on electrode surface is confirmed using cyclic voltammetry (CV) technique. Such immobilized bio-anode and bio-cathode show exquisite electrocatalytic activity towards glucose and O2, respectively. Most appealingly, P-EBFC can directly harvest energy from widely available beverages containing glucose such as Mountain Dew, Pepsi, 7up and fresh watermelon juice. This could provide potential application of P-EBFC as a portable power device.

Hemicelluloses are heteropolysaccharides existing in plant cell wall and seed, and they can be extracted or separated from plants as byproducts during the biomass pretreatment in biorefineries and the pulping in paper industry. The hemicelluloses have many applications such as in biofuels, platform chemicals, and materials. Producing packaging materials (films) is a potential high-value application of the hemicelluloses. However, native hemicelluloses are usually unable to form strong and durable films due to their short chain (low molecular weight), high hydrophilicity, and heterogeneous nature. Chemical and biological modifications could change the physicochemical properties of the hemicelluloses and thereby improve the strength and performance of the hemicellulose-based films. The present review extensively summarized and discussed the recent development and progress in hemicellulose modification strategies and methods for improving the formability and properties of the hemicellulose-based packaging films such as mechanical strength, processability, thermal stability, hydrophobicity, and oxygen and water vapor permeability, which include enzymatic treatment, esterification, etherification, oxidation, coupling, and crosslinking. The challenges and opportunities of hemicellulose as packaging materials were addresses.

Sustainable power generation for portable electronic devices is of high interest due to increasing energy demands. Miniaturized biofuel cells are well-reported for this purpose where ubiquitous fluids, like glucose or lactate, can be leveraged. However, such biofuel cells need enzymes to complete the catalysis, leading to many prevalent issues like the longevity of enzymes, complicated immobilization, additional mediators etc. Therefore, non-enzymatic glucose biofuel cells (NEGBFCs) are gaining interest due to their cost-effectiveness, high repeatability and excellent stability. However, based on our best knowledge such glucose biofuel cells are not reported in microfluidic environment, and therefore their potential is not exploited. Realization of the functionality of such NEGBFCs in a microscale is crucial to replace them with their enzymatic counterparts. In this work, for the first time, a microfluidic non-enzymatic glucose biofuel cell (μNEGBFC) is developed on a paper-based platform using metallic catalysts. The catalysts for electrocatalytic energy generation is fabricated using electrodeposition method and their detailed physicochemical characterizations are done. The μNEGBFC is capable of producing a power density of 12.5 μW/cm2 with a stable potential of 410 mV. This green power output can be used to operate low-power micro-devices and lab-on-chip sensors in a more continual and viable manner.

As a kind of industrial hazardous solid waste, paper mill sludge (PMS) was hard to treated by conventional process because of its high moisture, high organic content and and high environmental risk. The hydrothermal liquefaction (HTL) shows excellent potential for the conversion to a wide variety of organic matter with high water contents including various kinds sludge into fuels or value-added chemicals. In this paper, the liquefaction potential for PMS under different reaction temperatures were investigated, and the products were classified into several main components based on the results of GC-MS. The results showed that the highest yield of bio-oil was 44 % (wt/wt dry PMS without ash) at 340 °C with simply compound composition. And the bio-oil product has above 26 % long chain hydrocarbon and 22 % cycloketones. It has potential for conversion to biomass platform compounds. It can be used as bio-fuel for heat recovery of alkali recovery system of paper mill. So, adjusting different reaction temperatures of HTL, the properties of products can meet the different requirements for platform chemical and/or bio-oil fuel.