Water-Based Aerosol for Book Deacidification: Experimental Apparatus and Theoretical Interpretation of Results

One of the major problems in book conservation is the long-term deconstructive effect of acidity introduced into the paper by several additives, which, in the presence of humidity, generates a hydrogen cation with a strong catalytic role in cellulose depolymerization. Many types of treatment have been used in the past, but up to now, research for less-invasive, fast and cheap methods is still vividly ongoing. In this study, an approach to book deacidification is presented, where alkaline water solutions are administered to bound books in the form of micrometer-sized aerosol droplets, without using vacuum apparatus accessories. Alkaline clouds treatments were alternated with gentle air fluxes of drying steps. Few cycles are required to achieve uniform deacidification of books. The treatment could be conducted with proper apparatus on large volumes, resulting in rapid treatment time and low cost. The titration curve reporting the variation of book pH, with respect to the amount of absorbed alkaline aerosol, was built and interpreted in terms of a chemical model for the neutralization process. FTIR, PXRD and XRF spectroscopies were used to characterize the book chemistry. The effects of the treatment on the book were evaluated by measuring the degree of polymerization (DP) of the paper and the colorimetric coordinates of the paper and ink. Artificial aging tests revealed a general increase in the aging stability of the deacidified paper samples with respect to the untreated samples. Finally, the alkaline reserve data are discussed.

Optimizing two green-like biomass pretreatments for maximum bioethanol production in desirable banana pseudostem by effectively enhancing cellulose depolymerization and accessibility

Banana is an important fruit crop with enormous lignocellulose-rich pseudostem residues convertible for biofuels and biochemical production. By performing response surface methodological modeling, this study optimized green liquor (GL) and...

Water-soluble chlorophyll-binding proteins from Brassica oleracea allow for stable photobiocatalytic oxidation of cellulose by a lytic polysaccharide monooxygenase

Background Lytic polysaccharide monooxygenases (LPMOs) are indispensable redox enzymes used in industry for the saccharification of plant biomass. LPMO-driven cellulose oxidation can be enhanced considerably through photobiocatalysis using chlorophyll derivatives and light. Water soluble chlorophyll binding proteins (WSCPs) make it is possible to stabilize and solubilize chlorophyll in aqueous solution, allowing for in vitro studies on photostability and ROS production. Here we aim to apply WSCP–Chl a as a photosensitizing complex for photobiocatalysis with the LPMO, TtAA9. Results We have in this study demonstrated how WSCP reconstituted with chlorophyll a (WSCP–Chl a) can create a stable photosensitizing complex which produces controlled amounts of H2O2 in the presence of ascorbic acid and light. WSCP–Chl a is highly reactive and allows for tightly controlled formation of H2O2 by regulating light intensity. TtAA9 together with WSCP–Chl a shows increased cellulose oxidation under low light conditions, and the WSCP–Chl a complex remains stable after 24 h of light exposure. Additionally, the WSCP–Chl a complex demonstrates stability over a range of temperatures and pH conditions relevant for enzyme activity in industrial settings. Conclusion With WSCP–Chl a as the photosensitizer, the need to replenish Chl is greatly reduced, enhancing the catalytic lifetime of light-driven LPMOs and increasing the efficiency of cellulose depolymerization. WSCP–Chl a allows for stable photobiocatalysis providing a sustainable solution for biomass processing.

Water-soluble chlorophyll-binding proteins from Brassica oleracea allow for stable photobiocatalytic oxidation of cellulose by a lytic polysaccharide monooxygenase.

Background: Lytic polysaccharide monooxygenases (LPMOs) are indispensable redox enzymes used in industry for the saccharification of plant biomass. LPMO-driven cellulose oxidation can be enhanced considerably through photobiocatalysis using chlorophyll derivatives and light. Water soluble chlorophyll binding proteins (WSCPs) make it is possible to stabilize and solubilize chlorophyll in aqueous solution, allowing for in vitro studies on photostability and ROS production. Here we aim apply a WSCP-Chl α as a photosensitizing complex for photobiocatalysis with the LPMO, TtAA9. Results: We have in this study demonstrated how WSCP reconstituted with chlorophyll a (WSCP-Chl α) can create a stable photosensitizing complex which produces controlled amounts of H2O2 in the presence of ascorbic acid and light. WSCP-Chl α is highly reactive and allows for tightly controlled formation of H2O2 by regulating light intensity. TtAA9 together with WSCP-Chl α shows increased cellulose oxidation under low light conditions, and the WSCP-Chl α complex remains stable after 24 hours of light exposure. Additionally, the WSCP-Chl α complex demonstrates stability over a range of temperatures and pH conditions relevant for enzyme activity in industrial settings.Conclusion: With WSCP-Chl α as the photosensitizer, the need to replenish Chl is greatly reduced, enhancing the catalytic lifetime of light-driven LPMOs and increasing the efficiency of cellulose depolymerization. WSCP-Chl α allows for stable photobiocatalysis providing a sustainable solution for biomass processing.

Water-soluble chlorophyll-binding proteins from Brassica oleracea allow for stable photobiocatalytic oxidation of cellulose by a lytic polysaccharide monooxygenase

Background Lytic polysaccharide monooxygenases (LPMOs) are indispensable redox enzymes used in industry for the saccharification of plant biomass. LPMO-driven cellulose oxidation can be enhanced considerably through photobiocatalysis using chlorophyll derivatives and light. Water soluble chlorophyll binding proteins (WSCPs) make it is possible to stabilize and solubilize chlorophyll in aqueous solution, allowing for in vitro studies on photostability and ROS production. Here we aim apply a WSCP-Chl a as a photosensitizing complex for photobiocatalysis with the LPMO, TtAA9. Results We have in this study demonstrated how WSCP reconstituted with chlorophyll a (WSCP-Chl a) can create a stable photosensitizing complex which produces controlled amounts of H2O2 in the presence of ascorbic acid and light. WSCP-Chl a is highly reactive and allows for tightly controlled formation of H2O2 by regulating light intensity. TtAA9 together with WSCP-Chl a shows increased cellulose oxidation under low light conditions, and the WSCP-Chl a complex remains stable after 24 hours of light exposure. Additionally, the WSCP-Chl a complex demonstrates stability over a range of temperatures and pH conditions relevant for enzyme activity in industrial settings. Conclusion With WSCP-Chl a as the photosensitizer, the need to replenish Chl is greatly reduced, enhancing the catalytic lifetime of light-driven LPMOs and increasing the efficiency of cellulose depolymerization. WSCP-Chl a allows for stable photobiocatalysis providing a sustainable solution for biomass processing.

A ‘Trojan horse strategy’ for the development of a renewable leather tanning agent produced via an AlCl3-catalyzed cellulose depolymerization

The oligosaccharides from AlCl3-catalyzed cellulose depolymerization improve penetration of Al ion into the skin matrix for further crosslinking reaction.

Production of cellulase from Aspergillus niger and Trichoderma reesei mixed culture in carboxymethylcellulose medium as sole carbon

Septiani D, Suryadi H, Mun’im A, Mangunwardoyo W. 2019. Production of cellulase from Aspergillus niger and Trichoderma reesei mixed culture in carboxymethylcellulose medium as sole carbon. Biodiversitas 20: 3539-3544. Cellulase is one of hydrolytic enzymes that breakdown cellulose into glucose. Cellulases are promising to be applied in natural products which may improve the yield of bioactive in plant extract through cellulose depolymerization. Cellulases from mixed culture of Aspergillus niger and Trichoderma reesei can produce a high cellulase activity because of the synergism activity among endoglucanase, exoglucanase, and also β-glucoside. Cellulase production and partial purification of monoculture and mixed culture (1:1) of these fungi on carboxymethylcellulose media were investigated in this study. Total cellulase activity was measured by filter paper assay followed by protein estimation with Bradford method. The crude extract of Aspergillus niger monoculture has the highest cellulase activity (0.131 U/mL, P<005) followed by mixed culture (0.109 U/mL) and Trichoderma reesei (0.106 U/mL). The cellulase activity of partially purified cellulase from mixed culture significantly increased (0.335, 0.348, 0.374 U/mL, P<0.05) compared to crude extract along with stepwise addition of ammonium sulfate. Cellulase activity of mixed culture at 80% ammonium sulfate increase up to 2.238-fold and showed highest value (P<0.05) compared to monocultures. In conclusion, combination of Aspergillus niger and Trichoderma reesei fungi in carboxymethyl cellulose media followed by 80% ammonium sulfate precipitation can be a promising cellulase production with high cellulase activity.