An Eco-Friendly Production of a Novel and Highly Active Endo-1,4-beta-xylanase from Aspergillus clavatus

Aims: Here, we describe a novel way to produce an endo-1,4-beta-xylanase from Aspergillus clavatus using paper and pulp industry waste. Methodology: Optimal Aspergillus clavatus NRRL1 cultivation conditions were evaluated using minimal medium with different concentrations (1 to 10%) of paper sludge pretreated with HCl, during different periods (1 to 14 days), with different pH values (3.0; 3.5; 4.0; 4.5; 5.0; 5.5; 6.0; 6.5; 7.0; 7.5 and 8.0), different temperatures (25, 30, 35, and 40 ºC) and different mixing conditions (static and stirring). After that, the enzyme activity was determined by DNS (3,5-dinitrosalicylic acid), protein concentration was quantified by Bradford, SDS-PAGE was performed to evaluate the molecular mass, and TLC observed hydrolysis products. Results: The enzyme showed a molecular mass of 25 kDa, and its production has been highly improved by optimizing culture conditions. The best activity of this enzyme was obtained when A. clavatus was cultivated for 5 days, at 120 rpm, 5% paper sludge, pH 6.0, and 35 ºC. The degradation profile of the beechwood xylan by the crude extract containing the GH11 xylanase showed xylotriose as the main product, but xylotetraose and xylobiose were also produced in significant amounts. Conclusion: In addition to the fact that this xylanase has the property of producing large quantities of XOS (mainly xylotriose), it has the advantage of being obtained from recyclable waste of the pulp and paper industry. These facts confer great potential for future biotechnological and industrial applications.

The effect of protic solvents in the conversion of lignin from Earleaf Acacia tree

Lignin is one of main components of lignocellulosic along with cellulose and hemicellulose. It is a by-product of the paper and pulp industry, and has aromatic backbones making them an ideal renewable feedstock of aromatic compounds for a range of applications. Catalytic conversion of lignin from Earleaf Acacia tree was performed using high pressure/temperature reactor with Ru/C catalyst and protic solvents. The results showed that the conversion of lignin depends on the solvent polarity of protic solvents, and Ru/C catalyst enhanced the lignin conversion. Phenolic compounds are the main components of lignin conversion. Those compounds can be applied as a basement for bulk chemical and fuels.

Membrane Filtration Opportunities for the Treatment of Black Liquor in the Paper and Pulp Industry

Black liquor is a highly alkaline liquid by-product of the kraft pulping process, rich in organic molecules (hemicelluloses, lignin, and organic acids) and inorganic pulping chemicals such as sodium salts and sulphur-containing compounds. The release of this wastewater without further treatment could have serious environmental and financial implications. Therefore, a costly treatment process is used nowadays. Nanofiltration has been studied in the last few years as a promising alternative to recycle the cooking chemicals required for the separation of lignin and cellulose, but the development of pH-stable membranes with the potential to operate at industrial scales is fundamental in order to make this possible. In this study, the filtration performance of two in-house made membranes is evaluated and compared with a commercial NF membrane to determine the viability of their use for the treatment of black liquor. For this purpose, filtration experiments with simulated black liquor were performed. We identified that Membrane A has the higher potential for this application due to its competitive permeate flux (ca. 24 L m−2 h−1 at a trans-membrane pressure of 21.5 bar), and high rejection of organic components and salts from the cooking liquor (on average, 92.50% for the TOC, 84.10% for the CO32−, 88.70% for the sulphates, 73.21% for the Na+, and 99.99% for the Mg2+).

Potential applications of waste lignin from the paper and pulp industry in Viet Nam

The conversion of waste lignin from the paper and pulp industry is a potential process to produce chemicals and materials in the industry. With the development and the demand for the pulp and paper industry, the amount of waste lignin will increase remarkably. In Vietnam, the forest tree for the pulp industry is abundant, and the pulp industry has increased in recent years. In parallel, the government planned to develop the material resource and high-tech factories for this industry. In this work, we summarized the pulp and paper industry in Vietnam, then suggest the potential applications of waste lignin in several valuable products.

The application of lignin as renewable raw material in chemical industry

<p>The overutilization of fossil fuels will inevitably cause the global environmental problems and dwindling of available resources. For that reason, identifying renewable sustainable alternatives has attracted an increasing attention. Lignocellulosic biomass has been considered to be one of the most logical feedstock to replace traditional fossil resources as one of the most accessible renewable forms of carbon. One of the primary components of lignocellulosic biomass, next to hemicellulose and cellulose is lignin. It is a by-product in paper and pulp industry. Lignin is mainly used as fuel directly, without further utilization which is suggested to be a waste of natural resources. With this purpose, the valorization of lignin into value-added products needs particular attention of researchers. This review article focuses on chosen possible applications of lignin in chemical industry.</p>