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The pulp and paper industry discharges massive amount of wastewater containing hazardous organochlorine compounds released during different processing stages. Therefore, some cost-effective and nonpolluting practices such as enzymatic treatments are required for the potential mitigation of effluents released in the environment. Various xylanolytic enzymes such as xylanases, laccases, cellulases and hemicellulases are used to hydrolyse raw materials in the paper manufacturing industry. These enzymes are used either individually or in combination, which has the efficient potential to be considered for bio-deinking and bio-bleaching components. They are highly dynamic, renewable, and high in specificity for enhancing paper quality. The xylanase act on the xylan and cellulases act on the cellulose fibers, and thus increase the bleaching efficacy of paper. Similarly, hemicellulase enzyme like endo-xylanases, arabinofuranosidase and β-d-xylosidases have been described as functional properties towards the biodegradation of biomass. In contrast, laccase enzymes act as multi-copper oxidoreductases, bleaching the paper by the oxidation and reduction process. Laccases possess low redox potential compared to other enzymes, which need some redox mediators to catalyze. The enzymatic process can be affected by various factors such as pH, temperature, metal ions, incubation periods, etc. These factors can either increase or decrease the efficiency of the enzymes. This review draws attention to the xylanolytic enzyme-based advanced technologies for pulp bleaching in the paper industry.

The potential of alkaline cellulo-xylanolytic enzymes from non-pathogenic Bacillus subtilis strain was tested for deinking of photocopier waste paper. Cellulase and xylanase play a crucial role in deinking of different types of waste paper. Partial purification of cellulo-xylanolytic enzymes was carried out using ultrafiltration followed by ammonium sulfate precipitation. The ultrafiltered enzyme was used for deinking the photocopier waste paper along with chemical deinking. An enzyme dose of 0.6 IU/g and reaction time of 60 min for ultrafiltered cellulo-xylanolytic enzyme significantly increased deinking efficiency, tear index (9.52%) and folding endurance (5±2%) as compared to chemical deinking. There was improvement in strength properties such as tear index and double-fold along with freeness of pulp (18%). There was slight decrease in tensile index (0.6%) and burst index (16%) while ISO brightness remained unaffected. Enzymatic deinking (74.3%) by ultrafiltered cellulo-xylanolytic from Bacillus subtilis was found significant over conventional chemical deinking.

The applicability of bleached bamboo kraft pulp (Ba-BKP) was explored as a raw material for the manufacture of nanofibrillated cellulose (EN-NFC) made of enzyme-pretreated pulps and the effects of the EN-NFC on enhancing paper strength. The Ba-BKP was pretreated using an endo-glucanase enzyme at 50 °C and pH 6, after which the EN-NFC was made by micro-grinding. Bleached hardwood kraft pulp (Hw-BKP) was used as a control, and the non-enzymatic refining pretreatment of BKPs was compared with the enzyme pretreatment. The EN-NFC was incorporated into handsheets, and the sheet strengths were measured. The physical properties of the NFC made from the Ba-BKP were similar to those made from the Hw-BKP. The NFC prepared following enzyme pretreatment were smaller and more uniform than those pretreated with refining. The EN-NFC made from the Ba-BKP was effective at enhancing tensile index by 52.7%, and burst index by 210.2% when 2% of EN-NFC was added in the furnish, and those of handsheets containing the EN-NFC made from Hw-BKP showed the similar improvement. Therefore, Ba-BKP can be used as a raw material for the manufacture of EN-NFC that confers similar physical properties and strength enhancement to paper as those made from Hw-BKP.

The present study aimed to enzymatic deinking of waste papers and to valorize the effluent for biobutanol production. Application of fungal enzymatic cocktail (cellulase, amylase, xylanase, pectinase, lipase, and ligninase) on office used paper, newspaper, and ballpen written paper leading to improvement in brightness (84.91, 72.51, 76.69 % ISO), InKd (82.89, 68.95, 76.49%), κ-number (12.9, 13.6, and 13.1), opacity (27.91, 30.07, and 2.85%), tensile strength (49.24, 45.31, and 46.98 Nm/g), respectively and indices were consistent with chemical treated pulps. The quality of effluent generated during enzymatic deinking in respect to BOD and COD level was eco-friendlier than the chemical process. The enzyme-treated effluent was employed as supporting substrate for butanol (18.4 g/l) production by Clostridium acetobutylicum ATCC824. Material balance and life cycle assessment of the whole processes were evaluated to validate its industrial and environmental relevance.

A novel strain, designated WH2-56, was isolated from a slime sample collected from a paper company along the Yangtze River during March, 2018. Phylogenetic analyses based on 16S rRNA gene sequences revealed that strain WH2-56 was related to members of the genus Planomicrobium. Cellulolytic activity of the sample was screened and confirmed by Congo red-polysaccharide interactions and examined by broth culture using filter paper (FP) with no starch as the sole carbon source. Field emission scanning electron microscopy (FE-SEM) was used to confirm the delicate morphological changes of FP during bio-degradation. Different cellulosic materials were used to measure biodegradation effects and optimum incubation conditions. The activity of FPase and carboxymethyl cellulase (CMCase) were checked by 3,5-dinitrosalicylic acid (DNS agents) with different carbon sources, which showed a peak at 0.62 U/mL of CMCase on day 4, and at 0.38 U/mL of FPase on day 5.

Mixed office waste paper (MOWP) is a low cost, high quality and easily collected fiber source for the papermaking industry. Unfortunately, limits in the application of traditional deinking are related to the negative environmental impacts of using chemicals during the deinking process. Hence, enzymatic deinking has received growing attention in the last decade. This study investigates the effect of using the effective enzymes produced from Rhizopus microspores AH3 which is grown on watermelon peel waste (WPW) extract, as a bio-deinking method in the deinking of MOWP, which is difficult to recycle because of their ink type and printing process. The methodology involves preparation of samples, impregnation with water, enzymatic treatment, washing, papermaking, evaluation of the produced paper sheets. The evaluation includes determination of the optical and mechanical properties as well as topographic investigation via scanning electron microscope of produced paper sheets. The results showed that there is an improvement in both optical and mechanical properties of all paper sheets produced in this study. The best enhancement was for medium B30 which was extracted by boiling of WPW for 30 min. This treatment gave high enhancement because of the effect of the produced enzymes from Rhizopus microspores AH3, where cellulase, xylanase, lignin peroxidase, poly phenol oxidase and laccase were 1.62, 1.49, 1.38, 1.2 and 1.5 U/ml, respectively. Moreover, the tensile strain (maximum load) increased by about 77% as well as the brightness percentage achieved about 86.78% and the deinking ability was increased approximately 16%.

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.

Environmental pollution and the exploitation of fossil-based products are topical issues that should be a matter of concern to the global population. The production of bio-based substances from waste biomass is a way to reduce the consumption of fossil fuels and limit environmental pollution. Enzymatic catalysed saccharification of cellulose is an important step for the bio-conversion of biomass such as waste paper into glucose that could be utilized as a feedstock for the production of value added bioproducts and this process can also be considered as an alternative route of waste management. During this study, fresh cellulase enzyme from Trichoderma viride was incubated separately with seven different waste paper materials during twelve successive incubation periods of 2 h each. The amount of sugar released from each paper material during each incubation period was determined. The highest sugar concentration released from each paper materials was produced during the first incubation period except the filter paper for which the highest amount of sugar was produced during the 9th period of incubation. During these optimum sugar producing incubation periods the highest total sugar concentration was released from brown envelope paper (3.3 mg.mL-1 followed by foolscap paper (3.0 mg.mL-1) and office paper (2.8 mg.mL-1) while the lowest amount of sugar was released from Pick ’n Pay paper (0.6 mg.mL-1). The relative saccharification percentage was also calculated which showed that filter paper produced the highest amounts of sugar followed by newspaper, and foolscap paper with advertising paper from a retailer. Pick ’n Pay offered the highest resistance towards cellulase catalysed bio-conversion into sugar.

Paper has become the basic elixir in everyone's activities and usage of paper has increased day by day, the waste generated by paper is also enormous. The primary source of paper is wood (tree) yet, waste paper is environmentally good and biodegradable; however, it is the primary source of deforestation. Current research aims to find an alternate way to recycle paper in the biological approach. Hence in our work, twelve cellulose-producing bacteria were isolated, out of which one bacterial strain proved to be the best. Cellulase enzyme was extracted and purified, and used for enzymatic de-inking of photocopy papers. The optimal conditions for cellulase synthesis were at 60 °C, glucose as the only carbon source, and potassium nitrate as the nitrogen source. The enzyme demonstrated excellent de-inking at a lower pulp consistency of 3% with a 20% enzyme dose. The cellulose and hemicellulose levels decreased, which can be attributed to fiber breaking. Further, the changes in the functional groups identified by Fourier-transform infrared spectroscopy analysis and the changes in the surface morphology of the pulp fibers were obtained using scanning electron microscope analysis.

Currently, filter paper assay (FPA) is used to measure the hydrolytic potential of cellulase enzyme mixtures that are used to hydrolyze a range of cellulosic substrates. However, some of the Whatma...

A new procedures to minimize labor intensiveness and complexity that has long been recognized in cellulase filter paper activity measurement (FPAase) described by the international union of pure and applied chemistry (IUPAC) was developed. It follows the main idea of IUPAC with only exception finding at least two cellulase dilutions have optical densities slightly more and less than a reference optical density of an arbitrary fixed 2 mg absolute glucose amount after a red-ox color reaction and due to cellulase-filter paper hydrolysis. The yielding glucose amount difference as compared to this reference is expressed in terms of absorbance difference percent determined by 3,5-dinitrosalicylic acid (DNS), in case of cellulase is cellubiase rich. If not, an external supplemental portion should be added. The intersection of the line of these two cellulase dilutions with abscissa intersect a vertical at a hypothetical 0% absorbance difference percent corresponding to a critical cellulase dilution exactly release this fixed arbitrary 2 mg glucose amount value. The factor 0.37 of this critical cellulase dilution equals to its filter paper units expressed in FPU per ml.

The biological deinking method using microbial enzymes is quite promising and rather eco-friendly. In this paper, we discuss about the impact of enzymatic deinking of newspaper pulp using ligno-cellulosic (cellulase, xylanase and laccase) and lipolytic enzymes. The individual treatment of paper pulp with enzymes (cellulase/xylanase) could enhance the paper brightness to about 32.86% whereas combinational effect could enhance only about 28.67%. There was a release of chromophores from phenolic and hydrophobic compounds released during the deinking process. Physico-chemical parameters of effluents were also found to be within the standard limits and the metals like iron, lead and zinc were not detected in the enzyme assisted deinking effluent sample. The heavy metals in the paper pulp was found to be reduced after enzyme treatment. The obtained effluent was found have low phytotoxicity and was safe for agricultural applications. Hence, the present report was found to be a suitable enzymatic deinking process which was eco-friendly that results in non-toxic effluents. The method also provides an avenue in water resource recycling within industries.

Enzyme use has provided boost to the technoeconomics of many industrial processes. In this chapter, we summarize different cellulase-based industrial processes for preparation of paper, pulp, brewing products, and different foods. This review presents a brief chemistry and mechanism of cellulose degradation by the cellulase enzyme. Also, cellulase production abilities of many microbial species have been addressed in this chapter. Cellulase plays a major role in production of good-quality paper and pulp. It’s used to debark the biomass and to remove lignocellulosic part. This enzyme also has application in recycling of used paper by deinking and biobleaching. Cellulase enhances freeness and drainage ability of the fibers without compromising the brightness of the fibers. In brewing industry, cellulase in combination of other enzymes is used to extract the more sugar for better-quality alcohol production. Cellulases have a wide range of potential applications in food and beverage processing, production of fruit and vegetable juices, and improvement of methods for extraction, clarification, and stabilization.

The negative effect of solid waste on the environment is a topical issue effecting the global population. Waste paper is a major component of organic solid waste and cellulose a structural component of waste paper is a suitable biopolymer that could be resolved into glucose, a fermentable sugar. Also of concern to many sections of the farming community is the negative effect of garden snails on plants and fruits. When consumed by snails the cellulose section of plant materials can be hydrolysed by an enzyme system called cellulase into glucose which then is utilized as a resource of energy. Cellulase enzymes extracted from garden snails were incubated with seven different waste paper materials during ten successive incubating periods. Different sugar releasing patterns were constructed during the saccharification of the various paper materials indicating the different structural compositions of these paper materials. Foolscap paper showed the highest relative susceptibility for snail cellulase catalysed saccharification followed by brown envelope paper. The lowest amount of sugar was released during the degradation of newspaper and Pick n Pay advertising paper.

Microbial cellulases are industrially used enzymes that catalyze the cleavage of the glycosidic bonds of cellulose. This hydrolysis yields sugars that can be used in processes such as bioethanol production. These enzymes are mainly produced by fungi belonging to the genus Trichoderma via submerged or solid state fermentation with cellulosic materials as substrates. Recent publications have increasingly demonstrated that alternatives to T.reesei enzymes in the production of second generation biofuels exist. Here, cellulolytic activities of crude extracts obtained from a native isolate of T.asperellum from coffe pulp and a strain of T.reesei were evaluated. Solid state fermentations were performed using paper and sawdust as substrates. The activities were measured after 12 days of incubation. The extracts obtained from T.reesei showed higher cellulase and endoglucanase activities (6.5 and 5.8 U/g) than those obtained using T.asperellum (5.6 and 4.1 U/g) with paper as substrate. There were no significant differences between isolates when grownon sawdust. It was possible to verify that native T.asperellum was able to produce cellulases on lignocellulosic material such as moistened paper and sawdust without having undergone a chemical pretreatment.

The deinking of mixed office waste paper by cellulase, M/Las (modification of laccase aspartic acid system), and C-M/Las (cellulase synergistic modification of laccase aspartic acid system) was investigated. The fiber morphology parameters, hydrogen bond patterns, cellulose crystallinity, and fiber microstructure were observed via fiber quality analyzer (FQA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results showed that the effective residual ink concentration of enzyme deinked pulp decreased compared with blank pulp (pulp without enzymatic treatment). The deinking efficiencies of C-M/Las, cellulase, and M/Las were 18.17%, 14.01%, and 12.31%, respectively. FQA analysis indicated that the fiber length and curl index decreased, while the fiber width slightly increased. FTIR analysis revealed that after cellulase, M/Las, and C-M/Las treatment, the content of intermolecular hydrogen bonds increased by 14.65%, 13.37%, and 19.80%, respectively. This indicates that there is a synergistic effect between cellulase and M/Las. XRD showed that the cellulose crystallinity decreased after enzymatic deinking. SEM micrographs of fibers treated with enzymes revealed that the fiber surface became rough and more fibrils appeared. The water retention value was increased after enzymatic deinking.

Paper mill sludge (PMS) raises critical environmental issues due to its disposal problem, but its high sugar content and well-dispersed structure make it a great feedstock for biochemical production. The technical feasibility of integrating cellulase enzyme production into lactic acid (LA) fermentation from PMS was investigated in this study. The low ash content of PMS suggests a great potential for cellulase production. The enzyme produced using PMS without any treatment gave an activity of 7.8 FPU/ml, a performance comparable to the commercial enzyme, Cellic CTec 2. The LA yield from PMS with in-house enzyme was 64.7% and 73.7% at the enzyme loading of 10 and 15 FPU/g-glucan, respectively. The LA obtained was optically pure L- isomer with over 99% purity. The optimal condition of LA production by Bacillus coagulans was found to be 50 °C and pH 5.3 (with 50 g/L CaCO3). The nutrient effect of yeast extract (YE) and corn steep liquor (CSL) was substrate dependent, and CSL could substitute YE as an inexpensive nutrient when using PMS as a substrate.

As paper has become an important part of global consumption, there is a necessity to find a balance between production and resources, when an increase in paper production has been observed within past decades. Diverse technologies are being used for paper production one of them being use of enzyme of microbial origin for better bio-pulping and bio-bleaching results along with easier fibre grafting and de-inking. Though there are many applications of such enzymes in this industry, they are still at early development stage. The most essential feature of using enzymes is that it helps in eco-friendly bio-bleaching of pulps. Xylanase, cellulose free xylanase and occasionally use of laccase are the enzymes being used as a better alternative for reduction in the amount of environmental-polluting chlorine. Endo-β-xylanases, belonging to xylanases, is the key enzyme required for the enzymatic bleaching. The main purpose to adopt such techniques is to reduce the requirement of chlorine containing chemicals for bleaching. Enzymes further increases the pulp brightness making it easier for the industry to go chlorine free, along with improving fibre quality, producing better quality fibre. We will now discuss about the pulp industry and how xylanase enzyme helps in improving the productivity and revolution of the industry in detail in this chapter.

Development of qualitative properties and surface modification of mixed recycled 70% old newspaper and 30% old magazine pulp after enzymatic treatment with commercial cellulase was evaluated. The results of the present research demonstrated that the quality of the pulp and paper obtained from cellulase deinking process was comparable or even better than that from the chemical deinking. Under mild conditions of cellulase deinking (charge of 0.025–0.1% and duration time of 20 min, the paper with similar opacity as well as the increased brightness and whiteness values were obtained in comparison with non treated pulp or chemical one. Increasing reaction time to 30 min (at higher levels than 0.25% cellulase) and also enhancing the charge of cellulase to more than 0.1% (at different reaction times) were not advisable due to weak optical features of paper produced. The highest deinking efficiencies of 11.77 and 10.04% were obtained in enzymatic runs with cellulase (C2T2 and C1T3, respectively) but it was 9.3% for chemical deinking process (run of Cc). Increase in duration from 10 to 30 min at the maximum cellulase charge (0.2%) has been negatively influenced tensile index, breaking length, stretch and stiffness. In general, the best strength properties were obtained at middle charges of cellulase (0.025–0.05%) and duration times of 10–20 min. All strength characteristics were severely declined for run C4T3 (charge 0.2% and reaction time of 30 min). Run of C3T2 (charge 0.1% and reaction time of 20 min) was resulted in the higher tensile index (by 22%), stretch (by 9%) and stiffness (by 42%) compared to chemically deinked pulp. Cellulose crystallinity obtained by FTIR and XRD spectra was remarkably increased up to 0.2% cellulase but reduced severely at higher charges than 0.2% cellulase which implied declining the strength properties. In addition, FESEM micrographs of recycled fibers treated at different cellulase charge and duration times revealed surface modification and morphological changes like external fibrillation, peeling, fine production as well as rougher fiber surface due to cellulase act on the fiber surface. With increasing enzyme charge and duration time to some extent, fiber fibrillation have been developed and appearing much fibrils may result in the increased hydrogen bonding, number and contact area between fibers and consequently paper strength properties. However in harsh conditions particularly higher cellulase charges, the fiber structure is degraded, more fines appeared on fiber surface and strength properties are declined (especially tear resistance) due to a possible reduction in average fiber length.

Waste paper, a major fraction of municipal solid waste, has a potential to serve as renewable feedstock for the biorefineries of fuels, chemicals and materials due to rich in cellulose and abundant at low cost. This study evaluates the possibility of waste office paper (WOP) to serve as a potential feedstock for the biorefinery production of poly (3-hydroxybutyrate). In this study, the WOP was pretreated, enzymatically saccharified and the hydrolysate was used for PHB production. The hydrolysate mainly consists of glucose (22.70 g/L) and xylose (1.78 g/L) and the corresponding sugar yield was about 816 mg/g. Ammonium sulphate and C/N ratio 20 were identified as most favorable for high yield of PHB. The batch fermentation of Cupriavidus necator using the pretreated WOP hydrolysate resulted in cell biomass, PHB production and PHB content of 7.74 g/L, 4.45 g/L and 57.52%, respectively. The volumetric productivity and yield achieved were 0.061 g/L/h and 0.210 g/g sugar, respectively. The results suggested that WOP could be a potential alternative feedstock for the biorefinery production of bioplastics.

Enzymatic hydrolysis is considered an efficient and environmental strategy for the degradation of organic waste materials. Compared to mesophilic cellulases, thermostable cellulases with considerable activity are more advantageous in waste paper hydrolysis, particularly in terms of their participation in synergistic action. In this study, the synergistic effect of two different types of thermostable Chaetomium thermophilum cellulases, the endoglucanase CTendo45 and the cellobiohydrolase CtCel6, on five common kinds of waste papers was investigated. CtCel6 significantly enhanced the bioconversion process, and CTendo45 synergistically increased the degradation, with a maximum degree of synergistic effect of 1.67 when the mass ratio of CTendo45/CtCel6 was 5:3. The synergistic degradation products of each paper material were also determined. Additionally, the activities of CTendo45 and CtCel6 were found to be insensitive to various metals at 2 mM and 10 mM ion concentrations. This study gives an initial insight into a satisfactory synergistic effect of C. thermophilum thermostable cellulases for the hydrolysis of different paper materials, which provides a potential combination of enzymes for industrial applications, including environmentally friendly waste management and cellulosic ethanol production.

Anxi persimmon is a popular fruit because of its appealing flavor and rich nutrients such as polysaccharides. However, the harvested persimmon fruit softens and deteriorates quickly. This study explored the influences of the treatment of papers containing 1-methylcyclopropene (1-MCP) on the contents of cell wall polysaccharides and activities of cell wall-degrading enzymes in harvested Anxi persimmons, as well as its effect on fruit softening. The results demonstrated that, in comparison to the control Anxi persimmons, the Anxi persimmons treated with 1.35 μL/L 1-MCP manifested higher fruit firmness, higher contents of protopectin, cellulose, and hemicellulose, but a lower level of water-soluble pectin, lower activities of pectin methylesterase, polygalacturonase, cellulase, and β-galactosidase in Anxi persimmons during postharvest storage. These findings suggested that the treatment of papers containing 1.35 μL/L 1-MCP could retard softening of harvested Anxi persimmon fruit via inhibiting the degradation of cell wall polysaccharides.

Lipase enzyme has a critical role in deinking process along with other lignocellulosic enzymes. In this paper, we try to demonstrate the role of lipase in the enzyme cocktail used for enzymatic deinking. For this, we identified a potential lipolytic bacterium, Pseudomonas mendocina ED9 isolated from elephant dung with a molecular weight of 35 kDa. During the Box-Benhken model optimization, a maximum lipase activity of 105.12 U/g, which was 12.36-fold higher than the initial enzyme activity and 1.3-fold higher than the activity obtained during the Plackett Burman design, was achieved. A maximum lipase activity of 105.12 U/g was obtained after optimization. Ammonium sulphate (60%) precipitation resulted in a specific activity of 68.19 U/mg with a 1.4-fold purification and yield of 64%. Lipase from P. mendocina ED9 exhibited a Km of 0.5306 mM and Vmax of 25.0237 μmol/min/mg. A Δ brightness of approximately 14.5% were achieved during the enzymatic deinking using cocktail comprised of cellulase, xylanase and lipase. This reports the significant role and efficacy of lipase in enzyme cocktails for deinking applications. This formulation will reduce the pollution and environmental toxicity of conventional chemical deinking.

Paper and pulp industry is one of the biggest industries that generate waste material and waste water. Conversion of the industrial waste to renewable products through green process is one of the recent trends for the production of renewable fuels and other industrially important bioproducts like bioethanol, biobutanol and bioplastics. In pulp and paper industry, the main process for the production of cellulose pulp is Kraft process and various wastes are generated during this process. These wastes mainly contain the plant biomass which consists carbohydrates like cellulose, hemicellulose and other components of the wood. The present work focuses on the potential of utilizing paper industry rejects for the production of amino acids. The paper rejects were pretreated using mild acids and hydrolyzed enzymatically using cellulases. The effect of the acid pretreatment and hydrolysis on cellulose fiber structure were studied. The pretreatment and hydrolysis yielded 37% sugar from the paper rejects and the glucose obtained was used for subsequent lysine fermentation. Maximum sugar yield was observed when the pretreatment was carried out in a laboratory autoclave at 121 oC for 30 min at 15 lb pressure. When the pretreatment is carried out at higher temperature charring occurred which resulted in a reduction in glucose yield. The study was further outstretch by appraising the fermentability of using the paper reject hydrolyzateblended with CGXII synthetic medium in 1:1 ratio for L-lysine production using a strain of Corynebacterium glutamicum DM1729 which resulted in the production of 11.5 mg/ml lysine compared to 15.1 mg/ml obtained from pure synthetic medium.

Waste paper, one of the major components of municipal and industrial wastes, has considerable potential as a low-cost inductive feedstock for enzyme production. In this study, four kinds of waste papers were used for simultaneous production of cellulase and xylanase by Trichoderma longiflorum. The highest FPase activities (3.21 IU/mL and 2.97 IU/mL) were achieved using waste office paper (WOP) and corrugated board (CB), respectively, followed by magazine paper (MP, 2.51 IU/mL) and tissue paper (TP, 2.34 IU/mL). The maximum β-glucosidase activities (0.51 IU/mL) and xylanase activities (382.59 IU/mL) were obtained from CB substrates, which were higher than that in the reported literature using waste paper. Correspondingly, the soluble protein concentrations and SDS-PAGE profiles from CB fermentation revealed that more enzymes were secreted during fermentation compared with other waste paper. Moreover, the structural features of different waste paper were characterized by using SEM and XRD technique and revealed that the structural variations were mainly caused by the raw wood sources and papermaking processes, and further affected the fermentation capacity. In addition, a higher β-glucosidase activity of 0.80 IU/mL were obtained from the mixed carbon source of CB and wheat bran (WB), which were significantly improved and increased by 56.86% when compared with the CB as single carbon source. This study confirmed that the waste paper without pretreatment could be efficiently utilized as an inductive feedstock for simultaneous production of cellulase and xylanase by T. longiflorum. Therefore, these findings obtained from this study will provide a more widely insight into investigating the low-cost inductive feedstock for enzyme production, which were of great benefit both for the economy and environment.

Increasing environmental and sustainability concerns, caused by current population growth, has promoted a raising utilization of renewable bio-resources for the production of materials and energy. Recently, nanocellulose (NC) has been receiving great attention due to its many attractive features such as non-toxic nature, biocompatibility, and biodegradability, associated with its mechanical properties and those related to its nanoscale, emerging as a promising material in many sectors, namely packaging, regenerative medicine, and electronics, among others. Nanofibers and nanocrystals, derived from cellulose sources, have been mainly produced by mechanical and chemical treatments; however, the use of cellulases to obtain NC attracted much attention due to their environmentally friendly character. This review presents an overview of general concepts in NC production. Especial emphasis is given to enzymatic hydrolysis processes using cellulases and the utilization of pulp and paper industry residues. Integrated process for the production of NC and other high-value products through enzymatic hydrolysis is also approached. Major challenges found in this context are discussed along with its properties, potential application, and future perspectives of the use of enzymatic hydrolysis as a pretreatment in the scale-up of NC production., This work was carried out at the Biomass and Bioenergy Research Infrastructure (BBRI)- LISBOA-01-0145-FEDER-022059, supported by Operational Programme for Competitiveness andInternationalization (PORTUGAL2020), by Lisbon Portugal Regional Operational Programme (Lisboa 2020)and by North Portugal Regional Operational Program (Norte 2020) under the Portugal 2020 PartnershipAgreement, through the European Regional Development Fund (ERDF) and was supported by the PortugueseFoundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 and through Project EcoTech (POCI-01-0145-FEDER-032206/FAPESP 2018/07522-6) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope ofNorte2020-Programa Operacional Regional do Norte., info:eu-repo/semantics/publishedVersion

This study mainly investigated the feasibility of utilizing cellulase to enhance waste activated sludge (WAS) and paper waste (PW) co-fermentation for the generation of volatile fatty acids (VFAs). The introduction of cellulase effectively enhanced the co-fermentation efficiency, and the maximum VFAs generation reached 3014 mg COD/L with 60 mg cellulase/g TSS while it was 1512 mg COD/L in the control reactor. The presence of cellulase evidently improved the concentration of soluble bioavailable substrates (e.g., carbohydrates and proteins) via inducing the EPS disintegration and PW disruption. More importantly, the functional anaerobes (i.e., Macellibacteroides and Bacteroides) and the microbial activities (i.e., ATP, key acid-forming enzymes, and genetic expressions) that related with the VFAs biosynthesis were enriched and enhanced due to the stimulation of cellulase, contributing to the ultimate VFAs promotion. This study provided a novel strategy to recover valuable products from waste biomass with constructive mechanistic exploration.

This study investigated the extent of enzyme savings that could be achieved by recycling enzyme-containing supernatant or whole fermentation broth from simultaneous saccharification and fermentation (SSF) of paper waste sludge (PS). Kinetic models were developed to identify the preferred enzyme recycling method. Kinetic models accounted for the loss of enzyme activity with time and the effect of enzyme supplementation on ethanol concentrations and predicted the performance of PS fermentation with acceptable accuracy. Process performance of SSF cultures was maintained during successive recycling steps by recycling either the enzyme-containing supernatant or whole broth without resorting to enzyme separation methods. Recycling of enzymes in the clarified supernatant during 5 L bioreactor fermentations allowed up to 23% savings on the overall enzyme loading. Recycling enzymes in the supernatant further increased the ethanol concentration in the fermentation broth from 40 to 70 g/L. The combined advantages of high ethanol concentrations and savings on enzyme consumption, opens up the possibility of achieving significant improvements in the economic viability of ethanol production from lignocellulosic substrates.

To obtain chitosan (CTS) with narrower molecular weight distribution, CTS with weight-average molecular weight (MW) of 197.30 kDa was first metal complexed and then degraded into five CTSs with MW of 107.90, 56.48, 10.40, 5.67 (CTS-4) and 3.66 kDa. Decrease of MW did not cause a significant change in chemical structure of the residue CTS, but the crystal structure was transformed significantly. The moisture retention increased firstly and then decreased as the MW of CTS decreased. CTS-4 was superior to CTSs with other MW and propylene glycol in terms of the moisture retention. The lower water activity and increase of net isosteric heat were observed in CTS-4, which was due to the migration of immobilized water to a bound-state caused by mounting newly formed chain-end hydrophilic groups per unit weight. CTS-4 could effectively improve moisture retention, showing a potential to substitute commonly used humectant such as propylene glycol.

In recent years, there is an increase in global industrial utilization of wastepapers in the production of new one in which pulp and paper industries become one of the largest consumers of wood. Human needs result in harvesting of more trees with waste accumulation for proper disposal, which is a threat to global warming. The application of enzymes in deinking of recovered wastepapers is the major potential enzymatic applications in pulp and paper industries. Enzymes from either bacteria or fungi such as cellulase, xylanase, hemicellulase, pectinase, laccase, amylase, and lipase can be used to deink office wastepapers by enzymatic discharge of the ink particles from fiber surface or hydrolysis of the ink carrier. The lignifying enzymes and others being eco-friendly in nature hence provide a substantial way out to lessen the burden of employing toxic bleaching agents and other chemicals, thus helping in reducing deforestation and the release of harmful treatment effluents and correspondingly improving the quality and brightness of the bleached pulp. In this chapter, critical studies on the applications of microbial enzymes used for deinking of wastepapers in pulp and paper industries were examined.

Office waste paper constitutes an excellent low cost and high quality fibre source for the papermaking industry. Limitations in the application of conventional deinking to such paper are related to negative environmental impacts chemicals can cause, hence enzymatic deinking is receiving growing attention. This study is focused on the investigation of the effect of cellulases application on the deinking of office waste paper. The methodology involved: preparation of samples, impregnation, repulping, enzymatic treatment, flotation, papermaking, and finally evaluation of optical properties. Five preparations, working under acidic and neutral conditions, were tested (Cellusoft CR, Cellusoft AP, Novozymes 342, Cellusoft L, Accelerase 1500). The added amount of each enzyme preparation corresponded to 150 FPU/100 g paper. It was observed that the deinking experiments using enzymes achieved generally better results in comparison with those in which the enzymes were previously deactivated. Despite the positive effect of activated enzymes as compared to deactivated, the application of enzymes appeared disadvantageous compared with the conventional deinking in terms of specks surface of the deinked paper sheets. Apart from the type of enzyme preparation itself, another critical factor affecting the effectiveness of the enzymatic treatment was the addition of nitric acid used to achieve acidic conditions for the optimum enzyme function. To this end, further study have to be performed on enzyme preparations functioning under alkaline conditions as well as on other paper types while the effect of enzyme amount to the deinking and the subsequent impacts on mechanical strength of produced papers may be also investigated.

Deinking of recycled office (MOW) paper was carried out by using a flotation column and adding separately sodium hydroxide, and the enzyme Cellulase Thricodema Sp., as defibrillators. The de-inked cellulose fibers were characterized according to the standards of the paper industry, to compare the efficiency of the deinking of each chemical reagent used to hydrolyze the fibers and defibrillate them. The computational simulation of the molecular coupling between the enzyme and cellulose was performed, to establish the enzyme-cellulose molecular complex and then to identify the principal amino-acids of endo-β-1,4-D-glucanase in this molecular link, which are responsible for the hydrolysis of the cellulose. Experimental results show the feasibility to replace sodium hydroxide with the enzyme Cellulase Thricodema Sp., by obtaining deinked cellulose with similar optical and physical properties. The use of the enzyme instead of sodium hydroxide avoids the contamination of the residual water; in addition to that, the column is operated more easily, taking into consideration that the pH of the system goes from alkaline to neutral.

In the current scenario, used paper cups are disposed of without any proper treatment, thereby damaging the environment. Hence, the vermicomposting technique is preferred for managing these wastes. The ability of bacterial strains on cellulase enzyme (Endoglucanase, exoglucanase and β-glucosidase) production at altered pH and temperatures were focused in this study. Among nine bacterial strains Acinetobacter baumannii was found to have high enzyme activity. HPLC analysis confirms that about 45% of cellulose degradation occurred due to the action of bacterial consortia at 37 °C with pH 7. The overall period required for degradation takes only three months with the help of bacterial consortia while comparing to our previous study, which takes six months. The insilico study on three cellulose-degrading enzymes sequence were retrieved from NCBI, and analysed for multiple sequence alignment and phylogenetic tree construction. From the analysis, the endoglucanase SVK46152 (Acinetobacter baumannii) sequence got docked with cellopentaose with a high score value −11.07. Thereby we confirm that organism Acinetobacter baumannii was effective in paper cup degradation.

Waste disposal from paper and pulp industry is of great environmental concern. Sludge from recycled paper mills favors colonization with different microbial species due to its chemical composition. In this environment, the microbiota can express enzymes that hydrolyze celluloses and hemicelluloses, such as cellulases, β-glucosidases, and xylanases. Understanding microbiota living in such disposal may give directions to what kind of enzymes or bioproducts may be possible to obtain from this microorganism and how to deal with the waste during the process. We have accessed microbial community associated with two steps in the recycled paper sludge generation by high-throughput DNA sequencing: fibrous residue, and wastewater sludge. Bacteroidetes, Proteobacteria and Firmicutes phyla represented more than 96% of the total. From the eukaryote perspective, Vorticella was the most frequent in fibrous residue samples while Acanthamoeba was the most common on wastewater sludge samples. Among the isolates cellulase activity was detectable only from fungi isolates. Half of the bacterial isolates presented xylanase activity, and most of them in high level of activity. Both a metabarcoding and culturing approaches are valuable tools for enzymatic screening in industrial waste disposal.

Thermostable cellulases have wide variety of applications and distinctive advantages, but their low titer becomes the hurdle in their commercialization. In the present work, an assessment of optimum levels of significant factors (temperature, moisture ratio, inoculum size, and ammonium sulfate) and the effect of their interactions on production of thermostable CMCase, FPase, and β-glucosidase by Thermoascus aurantiacus RCKK under solid-state fermentation (SSF) was carried out using central composite design (CCD) of response surface methodology (RSM). The study revealed 33, 13, and 8 % improvement in FPase, CMCase, and β-glucosidase production, respectively. Moreover, crude cellulase from T. aurantiacus RCKK efficiently hydrolyzed office waste paper, algal pulp (Gracillaria verulosa), and biologically treated wheat straw at 60 °C with sugar release of about 830 mg/ml, 285 mg/g, and 260 mg/g of the substrate, respectively. The thermostable enzyme from T. aurantiacus RCKK holds potential to be used in biofuel industry.

One of the relatively inexpensive alternative energy sources in terms of production and relatively environment friendly was the development of bioethanol from urban wastes that contain many lignocellulose such as paper waste. This study characterizes the composition of cellulose, hemicellulose and lignin in blank HVS paper, inked HVS and newspaper. The results showed the predominate cellulose (49-60 %) while the lignin concentration was very low due to the removal of colors (lignin) in the manufacturing process. The experiments continued with synthesis of bioethanol through Simultaneous Saccharification and Fermentation (SSF) process. A combination of enzymes (Cellulase + Cellobiase) in 1:1 weight ratio and Saccharomyces cerevisiae was used for hydrolysis and fermentation in the SSF process. Paper waste from newspapers, inked HVS, and empty HVS papers were used as raw materials. The initial pH of SSF in the column was at pH 5. Variation of enzyme concentration was carried at 0.2, 0.3 and 0.5 g. The SSF process was carried out at incubation time of 6, 12, 24, 36, 48, 72, and 96 hours. The ink affected the concentration of bioethanol produced. In this study, the best bioethanol content was produced by inked HVS and Newspapers at 0.5 grams of enzyme with a concentration of 1531 and 1111 ppm, respectively.

Cellulase has by vast applications in the biofuel, pulp and paper, detergent and textile industries. The three components of the enzyme complex (endoglucanase, exoglucanase and β-glucosidase) can effectively depolymerize the cellulose chains in lignocellulosic substrate. Solid-state fermentation (SSF) by fungi is a preferable production route for cellulase because of its low cost, among other advantages. This work describes the cellulase production by Aspergillus niger NRRL3 grown on SSF. SSF was carried out on soybean hulls and waste paper as supports. The effect of the support on cellulase production was assessed under a completely randomized factorial design. The support-time interaction was significant for all the variables studied. Both materials were characterized in terms of water absorption index and critical humidity point. Samples of culture were analyzed with scanning electron microscopy (SEM) to study spores and fungal growth. Maximum endoglucanase activity was found at 96 h using soybean hulls as support (5914.29 U L−1), being four times higher than that obtained using waste paper at the same fermentation time. The exoglucanase activity in soybean hulls was maximal at 96 h (4551.19 U L−1), being 9.6 times higher than that obtained in waste paper at the same time. The maximum β-glucosidase activity in soybean hulls (984.01 U L−1) was reached at 96 h, being 1.7 times greater than that obtained in waste paper. Besides, the use of soybean hulls provided high volumetric productivities at shorter times, which may decrease production costs considering a scaled process. Fil: Boggione, María Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Procesos Biotecnológicos y Químicos Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Procesos Biotecnológicos y Químicos Rosario; Argentina Fil: Allasia, María Belén. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas; Argentina Fil: Bassani, Georgina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Procesos Biotecnológicos y Químicos Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Procesos Biotecnológicos y Químicos Rosario; Argentina Fil: Farruggia, Beatriz Monica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Procesos Biotecnológicos y Químicos Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Procesos Biotecnológicos y Químicos Rosario; Argentina

Media components were optimized using two-step statistical design of experiments for enhancing endoglucanase/carboxymethyl cellulase (CMCase) production by Trichoderma reesei RUT C30. A Placket-Burman design identified cellulose concentration and pH as the most significant variables, which influenced the CMCase activity. Central composite design was employed to optimize these selected parameters. The optimal activity was obtained at cellulose concentration 19.7 g/L and pH of 7.2. Under the optimized conditions, CMCase activity was 83.63 ± 1.86 IU/mL and filter paper activity was 2.58 ± 0.2 filter paper units per mL. Enzyme productivity was higher compared to previous reports. The enzyme produced from T. reesei was concentrated and was evaluated for deinking of printed paper, which demonstrated the suitability of the enzyme for this application.

Sixty fungal cultures were isolated from agricultural soil, industrial soil, forest canopy soil having decomposed leaf litter and compost samples collected from different regions of India. Fifteen fungal cultures were selected qualitatively for the production of xylanase and cellulases and were identified employing ITS, NS and MNS primers. The enzyme cocktail consisting of 3811 IU g(-1) of xylanase and 9.9 IU g(-1) of cellulase from Trichoderma longibrachiatum MDU-6 was selected quantitatively for the deinking of diverse paper wastes. The enzyme production increased two fold when produced at tray level in comparison with flasks. The enzyme cocktail was effective in the deinking of old newspaper samples with significant removal of chromophores, phenolics and hydrophobic compounds and less sugar loss. While in case of examination papers and laser printed papers, ink removal was not very significant. Moreover, the sugar loss was significantly high in case of examination papers. The deinking results were further confirmed with FTIR analysis. Deinked newspaper pulp sample shows brightness of 52%, which was 9.6% high than its control sample. The ERIC value for deinked newspaper pulp was found to be 655.9 ppm. Thereafter, the deinked newspaper pulp was examined under light microscope after differential staining with safranin and malachite green and also examined under scanning and transmission electron microscope, which revealed fibrillation and perforation.

Xylanases are useful in several industrial segments, including pulp and paper bleaching, animal feed, and bread-making processes. However, the industrial use of these enzymes is closely related to its production cost and its catalytic properties. The process of solid state fermentation enables the use of agro-industrial residues as substrates for microbial cultivation and enzymes production, reducing costs. In the present study, different cultivation parameters were evaluated for the xylanase production by the thermophilic fungus Thermoascus aurantiacus , by solid state fermentation, using agro-industrial residues as substrates. High production of xylanase (1701.9 U g -1 of dry substrate) was obtained using wheat bran containing 65% of initial moisture, at 120 h of cultivation, and 45°C. The xylanase showed optimal activity at pH 5.0 and 75°C; its stability was maintained at pH 3.0–11.0. The enzyme retained its catalytic potential after 1 h, at 75°C. The enzymatic extract produced under optimized conditions showed reduced activities of endoglucanase and FPase. Our results, including the xylanase production by T. aurantiacus in low-cost cultivation medium, high structural stability of the enzyme, and reduced cellulolytic activity, encourage the application of this enzymatic extract in pulp and paper bleaching processes.

Trichoderma reesei strain Rut-C30 was modified with enhanced beta-glycosidase (BGL) activity to balance the cellulase system and generated laccase (LAC) protein for lignin degradation. Initially, the binary plasmid p1300-w1 was constructed to express T. reesei bgl2 under the control of promoter P pki and T-nos terminator. Random insertion was performed via Agrobacterium tumefaciens-mediated transformation. A total of 353 mutants were obtained, and 34PTrb2 was exceptionally stable with increased FPA and BGL activity after screening for extracellular enzyme activity. Subsequently, 34PTrb2 was used as parent strain via the same method to insert the lac gene from Fomes lignosus, with promoter P gpd , followed by cbh1 signal peptide trss and T-nos as terminator. Several mutants successfully expressed enzyme LAC with stable activity of approximately 0.13 U/mL. The mutant 15Gsslac increased activity by 40.4% FPA compared with that of the host Rut-C30.

Hardwood bleached Kraft pulp was treated with an endoglucanase prior to Valley beating. The Valley-beaten pulp slurry was further ground with a particle grinder in order to evaluate the effect of enzyme beating on preparation of microfibrillated cellulose (MFC). The time required to make 100 mL Canadian Standard Freeness pulp slurry was greatly reduced by enzyme pre-treatment. The viscosity of the enzyme-beaten MFC slightly increased with grinder pass number; however, the rate of change in viscosity was much lower than that of non-enzyme-beaten MFC. The crystallinity of MFC decreased with grinder pass number for both cases. The drainage of the pulp slurry containing enzyme-beaten MFC was higher than that of the pulp slurry containing non-enzyme-beaten MFC. Further, the enzyme-beaten MFC subjected to the 10 passes grinding had the same tensile index as the MFC subjected to the 15 passes grinding. Thus, the mechanical energy for MFC manufacturing can be greatly reduced with enzyme beating.

The study investigates for the first time the possibility of using carbon rich paper recovery sludge, and nitrogen rich meat processing industry waste as cultivation medium for the production of high value enzymes needed in the respective industries. The complex cellulose rich deinking sludge was able to support the growth of many industrially relevant enzyme producing microorganisms (Bacillus licheniformis, Candida cylindracea, Aspergillus oryzae, Trichoderma reesei) and of recombinant enzyme producers (Escherichia coli and Pichia pastoris). Further detailed studies with Trichoderma reesei as model organism demonstrated that the organism was able to grow optimally in the presence of 40gL-1 paper sludge as carbon source and 67.5 gL-1 pasteurised blood as nitrogen source substituted in Mandels medium. Under these conditions cellulase activities up to 28.1 nkat FPU were achieved. Anyhow, to achieve these results pretreatment of both waste streams is inevitable. In summary, this study provides the practical basis for a valorisation systems of paper industry waste to produce valuable enzymes to be used on-site in paper processing or for other purposes.

The effect of cellulase pretreatment of bleached softwood kraft fiber before laboratory refining on the water vapor barrier and grease resistance properties of handsheets was investigated in this work. In contrast to no cellulase pretreatment, cellulase pretreatment at 0.5 filter paper units (FPU) combined with refining for 7500 revolutions was effective in reducing the water vapor transmission rate (WVTR, 50 % RH and 23 °C) of the paper by 83 % and achieving 100 % grease resistance over a 24-h test period. After cellulase pretreatment, the fiber morphology and hydrophobicity changed dramatically as a function of refining intensity. The role of cellulase pretreatment in reducing the WVTR and grease-stained areas was revealed on morphological observation by scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, as well as water contact angle testing.

Different types of pulp and paper sludge were used as raw materials for the production of a cocktail of lignocellulolytic enzymes of Trichoderma reesei RUT C-30 (T. reesei RUT C-30). The fungus were grown in pellets to produce cellulases (carbomethylcellulase, β-glucosidase) and hemicellulases (xylanase, β-xylosidase) in three types of sludge: primary (PS), secondary (SS) and mixed sludge (MS). The highest carbomethylcellulase activities obtained after 7 days of fermentation were 7.3, 4.8, and 1.5 IU/ml in MS, SS, and PS, respectively. Sludge modification such as the mixing SS and PS at 1:1 (v/v) ratio, the addition of ammonium sulfate as an inorganic nitrogen source, and the increase of the solids content were shown to improve enzyme production. The crude enzyme mixture obtained from the sludge samples showed a synergistic effect to hydrolyze various biomasses into monosugars. The tested biomasses included highly purified CMC, xylan from birch wood and lignocellulosic materials (corn stover and primary pulp and paper sludge). The addition of a surfactant (polysorbate 20) to the enzyme cocktail enhanced the saccharification efficiency of the sludge, in particular the hydrolysis of the corn stover which contains lignin. The obtained results contribute to the assessment of the feasibility of on-site low cost enzyme production at paper mills generating the sludge, or for neighboring or local biorefineries.

In this study, a microbial consortium from an acid-treated rumen fluid was used to improve the yields of H2 production from paper residues in batch reactors. The anaerobic batch reactors, which contained paper and cellulose, were operated under three conditions: (1) 0.5 g paper/L, (2) 2 g paper/L, and (3) 4 g paper/L. Cellulase was added to promote the hydrolysis of paper to soluble sugars. The H2 yields were 5.51, 4.65, and 3.96 mmol H2/g COD, respectively, with substrate degradation ranging from 56 to 65.4 %. Butyric acid was the primary soluble metabolite in the three reactors, but pronounced solventogenesis was detected in the reactors incubated with increased paper concentrations (2.0 and 4.0 g/L). A substantial prevalence of Clostridium acetobutylicum (99 % similarity) was observed in the acid-treated rumen fluid, which has been recognized as an efficient H2-producing strain in addition to ethanol and n-butanol which were also detected in the reactors.

The effective application of a biocatalyst based on recombinant enzyme preparations obtained using Penicillium verruculosum is studied for the modification of marketable bleached sulfate hardwood cellulose. The effect of treatment with cellulase complex on the structure, morphology, and surface state of cellulose fibers is evaluated. After biocatalytic exposure, cellulose is shown to have an improved capacity for beating and the formation of bonds in paper sheets, along with greater strength than the initial cellulose. Application of the enzymatic modification of cellulose in the paper industry during biotechnological processes allows a range of problems in the efficient use of energy and resources to be solved.

The studies dealt with the efficiency of a biocatalyst for modifying commercial bleached hardwood sulfate pulp. The biocatalyst was based on recombinant enzymatic agents prepared using Penicillium verruculosum fungus. The influence of the treatment with cellulase complex on the structure, morphology and surface state of cellulose fibers was estimated. It was shown that the biocatalytic treatment of cellulose led to improved beatability and bond-formation in paper sheets, to higher strength. Application of enzymatic modification of cellulose will help to solve some energy- and resource-saving problems in the paper industry.

A modified process consisting of an initial mechanical refining (R) followed by a low-alkali (5.5% NaOH) cold caustic extraction (CCE) and finally an endoglucanase (EG) treatment (R-5.5%CCE-EG) was investigated for upgrading paper-grade pulp to dissolving pulp. Results showed that compared to the conventional process (9%CCE-EG), the modified process can decrease the alkali concentration (from 9% to 5.5%) to achieve a similar hemicelluloses removal while simultaneously enhancing the Fock reactivity (from 62.2% to 81.0%). The improved results were due to the fact that the mechanical refining resulted in favorable fiber morphological changes, including increased pore volume/size, water retention value and specific surface area. Consequently, the hemicelluloses removal was enhanced even under the subsequent low-alkali CCE condition. A synergic effect of refining, low alkali concentration and enzymatic activation was responsible for the higher reactivity of resulting dissolving pulp.