The use of enzymes in secondary fiber (old paperboard containers) upgrading was investigated. The following aspects were analyzed: (i) the effect of several enzymes and (non-hydrolytic) cellulose-binding domains on the pulp and paper properties; (ii) factors influencing enzymatic treatment of secondary fiber: enzyme dosage and reaction time; and (iii) enzyme action on fractions with different fiber-length.In general, all the tested enzymatic preparations were able to improve the pulp drainability. In most cases this improvement was obtained at the expense of paper strength. The use of cellulose-binding domains allowed for the simultaneous increase in drainability and strength properties.
The effect of isolated cellulose binding domains (CBDs) on the hydrolysis of filter paper and microcrystalline cellulose by both cellobiohydrolase I and endoglucanase, was studied. CBDs were obtained by proteolysis from cellulases using a scaled-up variant of our previous method. Experiments were performed for different enzyme/substrate ratios in both the absence and presence of CBDs. Hydrolysis of filter paper by intact cellobiohydrolase I in the presence of additional CBDs was found to have a synergistic effect, leading to an increase of the sugar production of up to 30%. The effect was less pronounced using microcrystalline cellulose, where an increase up to 16% was observed. Similar trends were found during the hydrolysis of both substrates by endoglucanase.
Knowledge of composition of beverages volatile fraction is essential for understanding their sensory attributes. Analysis of volatile compounds predominantly resorts to gas chromatography coupled with mass spectrometry (GC-MS). Often a previous concentration step is required to quantify compounds found at low concentrations. This work presents a liquid-liquid microextraction method combined with GC-MS (LLME/GC-MS) for the analysis of compounds in fermented beverages and spirits. The method was validated for a set of compounds typically found in fermented beverages comprising alcohols, esters, volatile phenols, and monoterpenic alcohols. The key requirements for validity were observed, namely linearity, sensitivity in the studied range, accuracy, and precision within the required parameters. Robustness of the method was also evaluated with satisfactory results. Thus, the proposed LLME/GC-MS method may be a useful tool for the analysis of several fermented beverages, which is easily implementable in a laboratory equipped with a GC-MS.
Core-binding domains of fungal cellulases from Trichoderma reesei were purified using a new and simple technique. Cellulases were hydrolysed with papain and the binding domains were then separated from the digested mixture by ultrafiltration. The enzymatic digestion process was monitored using capillary electrophoresis. This methodology produced a yield of 85% of binding domains.
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