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We investigated the properties of the low molecular weight thermo-alkali-stable and mercury ion-tolerant xylanase production from Thermomyces dupontii KKU-CLD-E2-3. The xylanase was purified to homogeneity by ammonium sulfate, Sephadex G-100 and DEAE-cellulose column chromatography which resulted 27.92-fold purification specific activity of 56.19 U/mg protein and a recovery yield of 2.01%. The purified xylanase showed a molecular weight of 25 kDa by SDS-PAGE and the partial peptide sequence showed maximum sequence homology to the endo-1,4-β-xylanase. The optimum temperature and pH for its activity were 80 °C and pH 9.0, respectively. Furthermore, the purified xylanase can maintain more than 75% of the original activity in pH range of 7.0-10.0 after incubation at 4 °C for 24 h, and can still maintain more than 70% of original activity after incubating at 70 °C for 90 min. Our purified xylanase was activated by Cu 2+ and Hg 2+ up to 277% and 235% of initial activity, respectively but inhibited by Co 2+ , Ag + and SDS at a concentration of 5 mM. The K m and V max values of beechwood xylan were 3.38 mg/mL and 625 µmol/min/mg, respectively. Furthermore, our xylanase had activity specifically to xylan-containing substrates and hydrolyzed beechwood xylan, and the end products mainly were xylotetraose and xylobiose. The results suggested that our purified xylanase has potential to use for pulp bleaching in the pulp and paper industry.

Bioprocessing of pulp requires lignolytic as well as hemicellulolytic enzymes. The present study is the first report of a cocktail of laccase (L), xylanase (X), and mannanase (M), from a single bacterium for pulp biobleaching. A novel strain Bacillus tequilensis LXM 55 produced thermo-alkali stable L + X + M. On optimization higher enzyme yield (IUml -1 /fold increase) of laccase (396.35/24.16), xylanase (212.95/81.90) and mannanase (153.33/102.90) were achieved in the cocktail. Treatment of pulp with cocktail of enzymes led to 49.35% reduction in kappa number and considerable enhancement in the brightness (11.59%), whiteness (4.11%), and other pulp properties. Most importantly, no mediator system was required for the application of laccase. 40% less chlorine consumption was required to obtain the paper of the same quality as that of pulp treated without enzyme but with 100% chlorine. Therefore, this cocktail of enzymes is highly suitable for pulp biobleaching in the paper mill.

A paper-type colorimetric detector for identifying the degree of alkali ion concentration with the naked eye was fabricated using polydiacetylene/nanoporous rice husk silica (PDA/NP-SiO 2 ) nanocomposites as a potentially effective, rapid, and facile approach to detect alkali ion in aqueous solution. This study is worth investigating because it has the advantage of visually confirming the alkaline ion in aqueous solution without the aid of other analytical instruments directly at on-site as if pH indicator analysis. The concept of this study is the facile synthetic route of PDA and NP-SiO 2 . Nanoporous rice husk silica (NP-SiO 2 ) with a high specific surface area 450 m 2 /g was extracted from leached rice husk ash via a sol-gel process and utilized for efficient absorption of alkali ion. PDA was used as a material to differentiate the degree of alkali ion drawing using only the change of color. By compositing these two materials on the surface of filter paper using the spray drying method, the resulting PDA/NP-SiO 2 composites with NP-SiO 2 of the different specific surface areas showed a different change of color indicated by the degree of alkali ions even at a low concentration of less than 122 μm. The composite was further analyzed by UV spectroscopy for a change of color and images for screening depending on the alkali ion concentrations. The color response percentage of the PDA/NP-SiO 2 composites (PDA/449S; S BET 449.9213 m 2 /g) was 23.39% at 0.122 mM of NH 4 OH. Consequently, the result from this study showed the possibility of sensitively distinguishing the alkali ions ranging from pH 9.86 to pH 11.38 using only the naked eye, brought potential features that can be used as a convenient and facile primary water testing kit in practical applications., (Copyright © 2019. Published by Elsevier B.V.)

Bacteriophages find applications in agriculture, medicine, and food safety. Many of these applications can expose bacteriophages to stresses that inactivate them including acidic and basic pH. Bacteriophages can be stabilized against these stresses by materials including paper, a common material in packaging and consumer products. Combining paper and bacteriophages creates antibacterial materials, which can reduce the use of antibiotics. Here we show that adsorption on paper protects T4, T5, and T7 bacteriophage from acidic and basic pH. We added bacteriophages to filter paper functionalized with carboxylic acid (carboxyl methyl cellulose) or amine (chitosan) groups, and exposed them to pH from 5.6 to 14. We determined the number of infective bacteriophages after exposure directly on the paper. All papers extended the lifetime of infective bacteriophage by at least a factor of four with some papers stabilizing bacteriophages for up to one week. The degree of stabilization depended on five main factors (i) the family of the bacteriophage, (ii) the charge of the paper and bacteriophages, (iii) the location of the bacteriophages within the paper, (iv) the ability of the paper to prevent bacteriophage-bacteriophage aggregation, and (v) the sensitivity of the bacteriophage proteins to the tested pH. Even when adsorbed on paper the bacteriophages were able to remove E. coli in milk. Choosing the right paper modification or material will protect bacteriophages adsorbed on that material against detrimental pH and other environmental challenges increasing the range of applications of bacteriophages on materials., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Lignin in chemical pulping waste, or black liquor (BL), can be converted into various products via supercritical water gasification (SCWG). However, the inherited alkaline contents from the pulping chemicals may affect the product yields and properties. In this research, the influence of the residual alkali on the product distribution via SCWG of soda BL and kraft BL was evaluated. The SCWG was performed in a batch quartz reactor for 10 min at various temperatures (673, 773 and 873 K) and pressures (250, 300 and 400 bar). The highest hydrogen (H 2 ) production occurred at 873 K for the soda BL. The water-gas shift reaction with sodium ions played an important part in the H 2 production, while only small amounts of methane and carbon monoxide were detected. Hydrocarbons, carboxylic acids and esters were the dominant substrates in the liquid products, which denoted the potential of this method for bond cleaving of the lignin macromolecule. As a result, BL, which typically contains alkali salt, was an appropriate feedstock for the SCWG reaction to produce renewable fuel. This method not only has a positive influence on the generation of value added products from highly corrosive waste but also helps avoid some technical problems commonly encountered with direct firing in a recovery boiler.

Cellulase (mainly endoglucanase, EG) has been used in pulp modification for improving paper quality through environmentally friendly process. But low activity in alkaline pH and high filter paper activity (FPA) were still obstacles for extending the cellulase application in papermaking industry. In the study, an alkali-tolerant EG gene of Bacillus subtilis Y106 was homologous over-expressed for obtaining suitable enzyme used in pulp modification. The engineering strain could produce the crude enzyme with more alkali-tolerant EG and little PFA. Potential of the crude enzyme in modification of different pulps were investigated. It was found that the enzyme could be used for improving drainage and strength properties of pulps from softwood, hardwood and non-wood materials, especially non-wood pulp such as wheat straw pulp. The underlying mechanisms of pulp modification and different effects on various types of pulps by the EG treatment were also discussed by studying the change in fibers characteristics and fiber bonding.

Although the moderate load (COD of 5000-10,000 mg/L) and biodegradability of the APMP pulping effluent should allow biological treatment, toxic compounds in the effluent can interfere with this type of treatment. Studies were conducted to determine if treatment of the effluent with Aspergillus niger S13 was feasible. Under the optimized conditions (3% inoculum, pH 6, shaking at 160 rpm, 60-72 h, and 30°C), this fungus was able to remove about 97% of the methyl tertiary butyl ether (MTBE) extractives, and 60%, 77% and 43% of the chemical oxygen demand, turbidity and color even without a pre-flocculation step. These results are of practical interest in China because the APMP process has become popular, and efficient and cost-effective effluent treatment technologies are in high demand., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

AMDES (aminopropylmethyldiethoxysilane) was used to investigate the physicochemical and chemical events related to the introduction of aminoalkylalkoxysilanes in cellulosic materials. Using (29)Si CP-MAS and (1)H NMR to study the reactivity and structural modification of AMDES in the paper it was shown that polymerization occurs in situ. The distribution of the active compound on the surface of the fibers and throughout the fibers' thickness was visualized by SEM-EDS. A relation between moisture content, fiber swelling, and uptake of AMDES was found. To better represent old and brittle documents, the paper was predegraded by oxidation with sodium hypochlorite. XRD confirmed the advanced destruction of the amorphous areas of cellulose. Adding AMDES in the oxidized paper resulted in improved mechanical properties, a roughly unmodified degree of polymerization of cellulose, but a slight increase in the yellowing, probably due to several possible reaction products such as imines, amine, amides, and Maillard reactions products. The deacidification efficacy was established and the strengthening effect was shown to arise from the interaction of AMDES with the cellulose fibers.

Four different bacterial strains were isolated from pulp and paper mill sludge in which one alkalotolerant isolate (LP1) having higher capability to remove color and lignin, was identified as Bacillus sp. by 16S RNA sequencing. Optimization of process parameters for decolorization was initially performed to select growth factors which were further substantiated by Taguchi approach in which seven factors, % carbon, % black liquor, duration, pH, temperature, stirring and inoculum size, at two levels, applying L-8 orthogonal array were taken. Maximum color was removed at pH 8, temperature 35°C, stirring 200 rpm, sucrose (2.5%), 48 h, 5% (w/v) inoculum size and 10% black liquor. After optimization 2-fold increase in color and lignin removal from 25-69% and 28-53%, respectively, indicated significance of Taguchi approach in decolorization and delignification of lignin in pulp and paper mill effluent. Enzymes involved in the process of decolorization of effluent were found to be xylanase (54 U/ml) and manganese peroxidase (28 U/ml). Treated effluent was also evaluated for toxicity by Comet assay using Saccharomyces cerevisiae MTCC 36 as model organism, which indicated 58% reduction after treatment by bacterium.

An alkaline active xylanase, XynBYG, was purified from an alkaliphilic Bacillus pumilus BYG, which was newly isolated from paper mill effluent. It had an optimum pH of 8.0-9.0, and showed good stability after incubated at pH 9.0 for 120 min. The optimum temperature for the activity was 50°C, and the enzyme retained below 55% of its original activity for 30 min at 55°C. The gene coding for XynBYG consists of 687 bp and encodes 229 amino acids. Similarity analysis indicated that XynBYG belong to family 11 glycosyl hydrolases. Site-directed mutagenesis was performed to replace five sites (Tyr/Ser) to Arg/Glu and the results demonstrated that the optimum temperature of the mutant Y7 (S39R-T146E) increased 5°C and the half-life of inactivation (T1/2) at 60 and 65°C was 1 h and 25 min, respectively. Thus, it provides a potential xylanase that can meet the harsh conditions in the industrial applications.

The effect of hot-water extraction on alkaline pulping was investigated. The properties of black liquor and pulp strength of bagasse were analyzed. The extraction was conducted at 160 degrees C for 30min where 13.2% of the mass was dissolved in the extraction liquor. Untreated bagasse and extracted bagasse were digested by soda and soda-AQ processes at 17% and 15.5% (with 0.1% AQ) alkali charge (NaOH). Cooking temperatures were 160 degrees C and 155 degrees C respectively. The pulp from extracted bagasse had a lower Kappa number and a higher viscosity compared to the pulp from the untreated bagasse. The black liquor from pulping extracted bagasse had a lower solid content, a lower viscosity and a lower silica content, but a higher heating value than that from pulping of untreated bagasse. Hot-water extraction resulted in a significant decrease in bleaching chemical consumption and the formation of chlorinated organics. Pulp strength properties such as the tensile index and the burst index were found to be lower, but the tear index, bulk, opacity and pulp freeness were found to be higher when hot-water extraction was applied., (Copyright 2010 Elsevier Inc. All rights reserved.)

Combustion of industrial and domestic wastes produces significant amounts of dioxins (PCDDs, PCDFs, and coplanar PCBs). These wastes contain numerous kinds of materials, including inorganic elements, which may play an important role in dioxin formation upon combustion. Six paper samples--impregnated with NaHCO3, NaCl + fly ash, polyvinyl chloride (PVC), and PVC + NaHCO3--were combusted in a well-controlled incinerator at 512-760 degrees C and exhaust gases were analyzed for dioxins (PCDDs, PCDFs, and coplanar PCBs). Addition of fly ash, which contained high levels of Ca and Cl, to NaCl impregnated-newspaper increased total dioxin formation from 80.8 ngg(-1) to 139 ngg(-1) during combustion. Addition of NaHCO3 to PVC-impregnated newspaper increased total dioxin formation from 220 ngg(-1) to 288 ngg(-1). Formation of PCDDs from NaHCO3/PVC-impregnated newspaper were significantly less than that from newspaper impregnated with PVC alone. On the other hand, more PCDFs formed from NaHCO3/PVC-impregnated newspaper than from newspaper impregnated with PVC alone. Addition of NaHCO3 to a PVC-impregnated newspaper changed the production pattern of dioxins. PVC- impregnated newspaper produced the greatest amount of coplanar PCBs (12.3 ngg(-1)), which may be accounted for by the relatively high level of TEQ value (3.31 ng-TEQg(-1)) of this sample. Generally, addition of fly ash and alkali metals, such as Na, to paper samples increased the total dioxin formation in exhaust gases during combustion. The results suggest that alkali metals increase Cl concentrations at a reaction site by trapping chloride ions and/or chloride radicals and consequently increasing dioxin formation.

Three patients are presented, who sustained a unique type of burn injury while working in the pulp and paper industry in Canada. These patients suffered combination chemical (pH 11-13) and thermal (85-95 degrees C) injuries, when they were exposed to 'black liquor'--a solution which is used in the pulp and paper industry to convert wood chips to pulp. Black liquor can rapidly cause devastating thermal-corrosive burns to the skin, eyes, lungs, and upper gastrointestinal tract. One patient sustained a relatively minor, full skin thickness 3 per cent body surface area (BSA) injury to both feet and lower legs. The second patient, who was sprayed with the heated black liquor solution, sustained a full skin thickness injury to 40 per cent BSA and also suffered virtual loss of vision in one eye. The third patient, who was also sprayed with the solution, sustained a 98 per cent full skin thickness burn and severe inhalation injury, and died during day 1 postburn. Photographic documentation of all three patients is presented. The principles of treatment of this type of burn injury are reviewed. All of these burns were preventable.

Central corneal alkali burn injuries were induced in rabbits by applying five NaOH concentrations on uniformly soaked 7 mm filter paper discs. Clinical parameters were evaluated daily by microscopic examination and photography, and corneal myeloperoxidase levels were measured periodically. Satisfactory alkali burn models of corneal inflammation, vascularization and ulceration were developed by manipulating the alkali concentration.

The improvements of adding sodium borohyride to the alkali sulfite–anthraquninone (AS–AQ) pulping process on properties of pulp and paper sheets was investigated. These properties were compared to those of the AS–AQ and the ethanol addition to AS–AQ (ASAE) pulping processes. The screened yield increased with alkali sulfite–antraquinone–sodium borohyride (ASAB) pulping process and kappa number decreased with respect to the AS–AQ process. Tensile and burst index of paper sheets improved with the ASAB pulping process, and the tear index for the ASAB pulping process was slightly decreased compared to that of the AS–AQ and ASAE pulping processes. It was determined that whiteness and brightness of papersheets decreased by adding sodium borohyride to the AS–AQ pulping process, whereas the opacity of papersheets did not change clearly compared to AS–AQ and ASAE pulping processes. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this research was to develop an alkali pretreatment process prior to anaerobic digestion (AD) of pulp and paper sludge (PPS) to improve the methane productivity. Different concentrations of sodium hydroxide solution were used to pretreat PPS, and then followed by AD of PPS and monosodium glutamate waste liquor (MGWL). Laboratory-scale experiments were carried out in completely mixed bioreactors, 1L capacity with 700mL worked. Optimal amount of sodium hydroxide for organics solubilization in the step of pretreatment was 8g NaOH/100g TSsludge. Under this condition, the PPS flocs structure was well disrupted resulting in the void rate and fiber size decreased after pretreatment, and SCOD increased up to 83% as well as the peak value of VFA concentration attained 1040mgaceticacid/L during AD. The AD efficiency of PPS with and without pretreatment was evaluated. The highest methane yield under optimal pretreatment condition was 0.32m3 CH4/kgVSremoval, 183.5% of the control. The results indicated that alkali/NaOH pretreatment could be an effective method for improving methane yield with PPS. [Copyright &y& Elsevier]