Pub Date : 2023-02-28DOI: 10.35812/cellulosechemtechnol.2023.57.05
P. Ligero, A. de Vega, X. García
The aim of this work was to study and optimize the production of nano-size cellulose fibrils (NFC) by combined performic acid treatment, totally chlorine-free (TCF) bleaching and TEMPO-oxidation prior to mechanical treatment. For this purpose, a face-centered design was developed in order to optimize the independent variables governing performic treatment. Under the optimal conditions, a kappa index of 13 was achieved, which decreased to 2.2 after bleaching treatment. These low-lignin pulps were TEMPO-oxidized under different oxidizing conditions, while monitoring cellulose yield, carboxylic acid content and the degree of polymerization. The optimized conditions produced oxidized pulp with 1.4 mmol COOH/g dried nanofibre. Finally, this oxidized cellulose was subjected to high-pressure mechanical processing in order to obtain cellulose nanofibres. From the results, it can be concluded that neither the number of homogenizer passes nor the pressure affected to diameter of fibrils.
{"title":"DEVELOPMENT OF COMBINED ORGANOSOLV-TEMPO OXIDATION TREATMENT FOR OBTAINING CELLULOSE NANOFIBRES","authors":"P. Ligero, A. de Vega, X. García","doi":"10.35812/cellulosechemtechnol.2023.57.05","DOIUrl":"https://doi.org/10.35812/cellulosechemtechnol.2023.57.05","url":null,"abstract":"The aim of this work was to study and optimize the production of nano-size cellulose fibrils (NFC) by combined performic acid treatment, totally chlorine-free (TCF) bleaching and TEMPO-oxidation prior to mechanical treatment. For this purpose, a face-centered design was developed in order to optimize the independent variables governing performic treatment. Under the optimal conditions, a kappa index of 13 was achieved, which decreased to 2.2 after bleaching treatment. These low-lignin pulps were TEMPO-oxidized under different oxidizing conditions, while monitoring cellulose yield, carboxylic acid content and the degree of polymerization. The optimized conditions produced oxidized pulp with 1.4 mmol COOH/g dried nanofibre. Finally, this oxidized cellulose was subjected to high-pressure mechanical processing in order to obtain cellulose nanofibres. From the results, it can be concluded that neither the number of homogenizer passes nor the pressure affected to diameter of fibrils.","PeriodicalId":10130,"journal":{"name":"Cellulose Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43347269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-28DOI: 10.35812/cellulosechemtechnol.2023.57.01
M. Stanescu
"Dramatic climate changes impose the implementation of new non-polluting technologies to ensure a sustainable development. The textile industry is very polluting, with high energy and water footprints, as well as discharges of toxic emissions and high waste water amounts. Thus, new, less polluting processes have to be brought in to decrease the environmental impact of this industry. Cellulosic fibers play an important role among the raw materials of textile industry. Classical treatments of natural cellulosic fibers use many chemical reagents and a large quantity of water. The progress registered lately in enzymes’ production – regarding their preparation reproducibility and their stability as well – offer a good alternative to chemical reagents. The paper discusses the latest achievements in the application of enzymes for natural cellulosic fibers processing. The state of the art and recommendations for the future are presented."
{"title":"APPLICATIONS OF ENZYMES IN PROCESSING CELLULOSIC TEXTILES – A REVIEW OF THE LATEST DEVELOPMENTS","authors":"M. Stanescu","doi":"10.35812/cellulosechemtechnol.2023.57.01","DOIUrl":"https://doi.org/10.35812/cellulosechemtechnol.2023.57.01","url":null,"abstract":"\"Dramatic climate changes impose the implementation of new non-polluting technologies to ensure a sustainable development. The textile industry is very polluting, with high energy and water footprints, as well as discharges of toxic emissions and high waste water amounts. Thus, new, less polluting processes have to be brought in to decrease the environmental impact of this industry. Cellulosic fibers play an important role among the raw materials of textile industry. Classical treatments of natural cellulosic fibers use many chemical reagents and a large quantity of water. The progress registered lately in enzymes’ production – regarding their preparation reproducibility and their stability as well – offer a good alternative to chemical reagents. The paper discusses the latest achievements in the application of enzymes for natural cellulosic fibers processing. The state of the art and recommendations for the future are presented.\"","PeriodicalId":10130,"journal":{"name":"Cellulose Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46418982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-28DOI: 10.35812/cellulosechemtechnol.2023.57.06
Khushboo Kapoor, A. Tyagi, Mukul Das, Virendra Kumar
"Sugarcane bagasse is an abundant source of cellulose and hemicelluloses that could be hydrolyzed to yield fermentable sugars, which can be utilized for the production of biofuel and other high-value bio-chemicals. To do so, it has to be made accessible for hydrolyzing chemicals and enzymes, and radiation exposure is one of the most effective and green techniques, among other physico-chemical processes. The present study investigated the effects of gamma and electron beam (e-beam) irradiation on sugarcane bagasse, with respect to changes in its physical, chemical, thermal and morphological characteristics. Sugarcane bagasse was irradiated with gamma radiation, using Co60 at a dose rate of 2.5 kGy/h, and electron beam at a dose rate of 2.5 kGy/pass. The maximum dose was varied up to 1000 kGy and changes in the physico-chemical characteristics of bagasse were observed at 500 kGy dose exposure. The physical appearance of bagasse (after gamma and e-beam treatments) changed from off-white to yellow in colour, while beyond 500 kGy, the samples became fluffy. With an increase in the radiation dose, the cellulose content reduced from 48% to 36%, following Co60 gamma exposure, and to 16% after e-beam exposure at 1000 kGy. The hemicellulose content was found to reduce from 31% to 16% after 1000 kGy of Co60 gamma exposure, but after e-beam radiation, it increased to 39%. The lignin fraction did not change much after any of the treatments, and was found to be in the range of 19-20% and 17-23%, after gamma and e-beam radiation exposure, respectively. In most of the irradiated samples, X-ray diffraction (XRD) confirmed a significant increase in crystallinity index with the increase in the radiation dose up to 1000 kGy. However, a decrease in the crystallinity index of bagasse was observed after e-beam irradiation. Scanning electron microscopy (SEM) analysis showed remarkable disruption of the structure, caused by high energy irradiations (gamma and e-beam). The particle size analysis indicated fragmented particles on increasing irradiation doses, but the distribution is more prominent in the case of the e-beam treatment. A lowering of the derivative thermogravimetric (DTG) peak from 339 °C in raw bagasse to 295 °C and 303 °C, for the samples subjected to gamma and e-beam radiation, respectively, was observed, in the thermal study of the biomass. The physico-chemical changes observed during the study clearly indicated that ionizing radiation exposure of lignocellulosic biomass led to the disintegration of its matrix, which may give easy access to hydrolytic chemicals or enzymes. Thus, it can be concluded that, although both ionizing radiations investigated here can fulfill the objective of disintegrating the biomass structure, gamma is more effective than e-beam radiation."
{"title":"COMPARATIVE ANALYSIS OF MORPHOLOGICAL AND STRUCTURAL CHANGES IN GAMMA AND ELECTRON BEAM IRRADIATED SUGARCANE BAGASSE","authors":"Khushboo Kapoor, A. Tyagi, Mukul Das, Virendra Kumar","doi":"10.35812/cellulosechemtechnol.2023.57.06","DOIUrl":"https://doi.org/10.35812/cellulosechemtechnol.2023.57.06","url":null,"abstract":"\"Sugarcane bagasse is an abundant source of cellulose and hemicelluloses that could be hydrolyzed to yield fermentable sugars, which can be utilized for the production of biofuel and other high-value bio-chemicals. To do so, it has to be made accessible for hydrolyzing chemicals and enzymes, and radiation exposure is one of the most effective and green techniques, among other physico-chemical processes. The present study investigated the effects of gamma and electron beam (e-beam) irradiation on sugarcane bagasse, with respect to changes in its physical, chemical, thermal and morphological characteristics. Sugarcane bagasse was irradiated with gamma radiation, using Co60 at a dose rate of 2.5 kGy/h, and electron beam at a dose rate of 2.5 kGy/pass. The maximum dose was varied up to 1000 kGy and changes in the physico-chemical characteristics of bagasse were observed at 500 kGy dose exposure. The physical appearance of bagasse (after gamma and e-beam treatments) changed from off-white to yellow in colour, while beyond 500 kGy, the samples became fluffy. With an increase in the radiation dose, the cellulose content reduced from 48% to 36%, following Co60 gamma exposure, and to 16% after e-beam exposure at 1000 kGy. The hemicellulose content was found to reduce from 31% to 16% after 1000 kGy of Co60 gamma exposure, but after e-beam radiation, it increased to 39%. The lignin fraction did not change much after any of the treatments, and was found to be in the range of 19-20% and 17-23%, after gamma and e-beam radiation exposure, respectively. In most of the irradiated samples, X-ray diffraction (XRD) confirmed a significant increase in crystallinity index with the increase in the radiation dose up to 1000 kGy. However, a decrease in the crystallinity index of bagasse was observed after e-beam irradiation. Scanning electron microscopy (SEM) analysis showed remarkable disruption of the structure, caused by high energy irradiations (gamma and e-beam). The particle size analysis indicated fragmented particles on increasing irradiation doses, but the distribution is more prominent in the case of the e-beam treatment. A lowering of the derivative thermogravimetric (DTG) peak from 339 °C in raw bagasse to 295 °C and 303 °C, for the samples subjected to gamma and e-beam radiation, respectively, was observed, in the thermal study of the biomass. The physico-chemical changes observed during the study clearly indicated that ionizing radiation exposure of lignocellulosic biomass led to the disintegration of its matrix, which may give easy access to hydrolytic chemicals or enzymes. Thus, it can be concluded that, although both ionizing radiations investigated here can fulfill the objective of disintegrating the biomass structure, gamma is more effective than e-beam radiation.\"","PeriodicalId":10130,"journal":{"name":"Cellulose Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49510739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-28DOI: 10.35812/cellulosechemtechnol.2023.57.02
A. Yakubu, A. Vyas
"Industrial utilization of waste paper in the production of a new one is increasing globally. Currently, the pulp and paper industry is one of the largest consumers of wood. Based on the demand, due to global economic growth, an increasing number of trees are harvested each year, also leading to increased amounts of wastes and pollutants, which represent a serious hazard for the environment. Chemical agents, such as sodium hydroxide, hydrogen peroxide, sodium carbonate, diethylenetriaminepentacetic acid, sodium silicate and surfactants, are used in large quantities by paper industries as part of the conventional methods of deinking waste paper, leading to the need to apply expensive wastewater treatments in order to meet environmental regulations. On the other hand, enzymes, such as cellulase, lipase, xylanase, pectinase, hemicellulase, amylase and esterase, can substitute conventional chemical methods of deinking waste papers. These enzymes have been reported to be environmentally friendly, as compared to the chemicals involved in conventional methods. Several decades ago, it was established that microbial enzymes might be useful in the processing of paper, since it is composed of natural polymers, such as cellulose, hemicelluloses and lignin. However, despite their enormous potential, the industrial use of these enzymes is still limited, being affected by lack of microbial strains capable of generating a high amount of alkaline cellulase. This paper provides an insight into recent research performed with the objectives of optimizing alkaline cellulase enzymes production and applying them in pulp and paper processes."
{"title":"INDUSTRIAL APPLICATION OF ALKALINE CELLULASE ENZYMES IN PULP AND PAPER RECYCLING: A REVIEW","authors":"A. Yakubu, A. Vyas","doi":"10.35812/cellulosechemtechnol.2023.57.02","DOIUrl":"https://doi.org/10.35812/cellulosechemtechnol.2023.57.02","url":null,"abstract":"\"Industrial utilization of waste paper in the production of a new one is increasing globally. Currently, the pulp and paper industry is one of the largest consumers of wood. Based on the demand, due to global economic growth, an increasing number of trees are harvested each year, also leading to increased amounts of wastes and pollutants, which represent a serious hazard for the environment. Chemical agents, such as sodium hydroxide, hydrogen peroxide, sodium carbonate, diethylenetriaminepentacetic acid, sodium silicate and surfactants, are used in large quantities by paper industries as part of the conventional methods of deinking waste paper, leading to the need to apply expensive wastewater treatments in order to meet environmental regulations. On the other hand, enzymes, such as cellulase, lipase, xylanase, pectinase, hemicellulase, amylase and esterase, can substitute conventional chemical methods of deinking waste papers. These enzymes have been reported to be environmentally friendly, as compared to the chemicals involved in conventional methods. Several decades ago, it was established that microbial enzymes might be useful in the processing of paper, since it is composed of natural polymers, such as cellulose, hemicelluloses and lignin. However, despite their enormous potential, the industrial use of these enzymes is still limited, being affected by lack of microbial strains capable of generating a high amount of alkaline cellulase. This paper provides an insight into recent research performed with the objectives of optimizing alkaline cellulase enzymes production and applying them in pulp and paper processes.\"","PeriodicalId":10130,"journal":{"name":"Cellulose Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42244144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-28DOI: 10.35812/cellulosechemtechnol.2023.57.07
Mouroug Thaher Zyadeh, I. Hamadneh, Mahmoud ABDEL-RAHMAN Kasrawi, Haythem A. Saadeh, M. Shahein
"This study aimed to synthesize a cellulose-based hydrogel as a new green fertilizer with slow-release properties. The cellulose-based hydrogel was prepared by reacting carboxymethyl cellulose solution with cellulose and was crosslinked with citric acid. The structure of the hydrogel was confirmed by FT-IR. The nitrogen fertilizers KNO3 and (NH4)2SO4 were loaded during the preparation. The swelling behavior of the hydrogel in deionized water was studied, in addition to the effects of pH, salinity, and drought on swelling behavior. Finally, the fertilizer release behavior in deionized water and a soil mix was investigated, in addition to the soil water content. The optimum hydrogel formulation (HG) showed good absorbance capacity – of 450%, and good durability for one month in deionized water. The swelling-deswelling studies revealed its sensitivity to different solutions. The HG loaded with nitrogen fertilizers showed slow, sustained release rates in deionized water and the soil mix; the cumulative release rates approached 70%, 65%, 60%, and 65%, respectively. Moreover, soil moisture was improved by the addition of the hydrogel by 100% on day 20 and reached 12% on day 30. The results were in accordance with the Committee of European Normalization standards. In conclusion, this new green hydrogel could be used in agricultural applications."
{"title":"SYNTHESIS OF CELLULOSE-BASED HYDROGEL FOR REGULATING THE RELEASE OF NITROGEN FERTILIZER","authors":"Mouroug Thaher Zyadeh, I. Hamadneh, Mahmoud ABDEL-RAHMAN Kasrawi, Haythem A. Saadeh, M. Shahein","doi":"10.35812/cellulosechemtechnol.2023.57.07","DOIUrl":"https://doi.org/10.35812/cellulosechemtechnol.2023.57.07","url":null,"abstract":"\"This study aimed to synthesize a cellulose-based hydrogel as a new green fertilizer with slow-release properties. The cellulose-based hydrogel was prepared by reacting carboxymethyl cellulose solution with cellulose and was crosslinked with citric acid. The structure of the hydrogel was confirmed by FT-IR. The nitrogen fertilizers KNO3 and (NH4)2SO4 were loaded during the preparation. The swelling behavior of the hydrogel in deionized water was studied, in addition to the effects of pH, salinity, and drought on swelling behavior. Finally, the fertilizer release behavior in deionized water and a soil mix was investigated, in addition to the soil water content. The optimum hydrogel formulation (HG) showed good absorbance capacity – of 450%, and good durability for one month in deionized water. The swelling-deswelling studies revealed its sensitivity to different solutions. The HG loaded with nitrogen fertilizers showed slow, sustained release rates in deionized water and the soil mix; the cumulative release rates approached 70%, 65%, 60%, and 65%, respectively. Moreover, soil moisture was improved by the addition of the hydrogel by 100% on day 20 and reached 12% on day 30. The results were in accordance with the Committee of European Normalization standards. In conclusion, this new green hydrogel could be used in agricultural applications.\"","PeriodicalId":10130,"journal":{"name":"Cellulose Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47732290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-28DOI: 10.35812/cellulosechemtechnol.2023.57.14
J. Gigac, M. Fišerová, A. Russ
"In the present work, various surface treatments of base paper were investigated in order to make it suitable for application in printed electronics. A functional coating based on silica pigment was preceded by PVOH-containing precoating, and differently surface treated papers were characterized in terms of surface roughness, relative area of surface pores, wettability, printability and by FTIR spectroscopy. The precoating had a significant effect on the constriction of through-pores, the reduction of their number, and on the permeability of the functional coating, and it increased the dynamic contact angle of the liquids. Analysis of FTIR spectra of precoated and functionally coated paper confirmed a higher content of polyvinyl alcohol binder and cationic polymer in the functional coating, compared to that of functionally coated paper, without precoating. SEM analysis showed that the silver layer of the RFID antenna printed by inkjet on the precoated and functionally coated paper was continuous. Better printability of the precoated and functionally coated paper, compared to the functionally coated paper, without precoating, was also confirmed by higher electrical conductivity of the dipole of the RFID antenna, which reached the level of the antenna printed on a commercial inkjet PET film."
{"title":"\"EFFECT OF PRECOATING ON PROPERTIES OF FUNCTIONAL COATING AND ELECTRICAL CONDUCTIVITY OF INKJET-PRINTED ELECTRONICS\"","authors":"J. Gigac, M. Fišerová, A. Russ","doi":"10.35812/cellulosechemtechnol.2023.57.14","DOIUrl":"https://doi.org/10.35812/cellulosechemtechnol.2023.57.14","url":null,"abstract":"\"In the present work, various surface treatments of base paper were investigated in order to make it suitable for application in printed electronics. A functional coating based on silica pigment was preceded by PVOH-containing precoating, and differently surface treated papers were characterized in terms of surface roughness, relative area of surface pores, wettability, printability and by FTIR spectroscopy. The precoating had a significant effect on the constriction of through-pores, the reduction of their number, and on the permeability of the functional coating, and it increased the dynamic contact angle of the liquids. Analysis of FTIR spectra of precoated and functionally coated paper confirmed a higher content of polyvinyl alcohol binder and cationic polymer in the functional coating, compared to that of functionally coated paper, without precoating. SEM analysis showed that the silver layer of the RFID antenna printed by inkjet on the precoated and functionally coated paper was continuous. Better printability of the precoated and functionally coated paper, compared to the functionally coated paper, without precoating, was also confirmed by higher electrical conductivity of the dipole of the RFID antenna, which reached the level of the antenna printed on a commercial inkjet PET film.\"","PeriodicalId":10130,"journal":{"name":"Cellulose Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44463899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-28DOI: 10.35812/cellulosechemtechnol.2023.57.08
İ.Y. Mol, F. Cengiz Çallıoğlu, Hülya Kesici Güler, E. Sesli Çetin, G. Bilir
"Herein, it was aimed to achieve antibacterial cellulose acetate (CA) nanofiber production and characterization. Firstly, solution properties, such as viscosity, conductivity and surface tension, were determined. Secondly, CA/zinc oxide (ZnO) composite nanofibers were produced with optimum process parameters via the electrospinning method. Then, the electrospun nanofibers were characterized by SEM, EDX, DSC, TGA, XRD, air permeability and water vapor permeability testing. Lastly, antibacterial activity tests were carried out in accordance with the AATCC100 method, against Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922). According to the results, solution conductivity decreased and surface tension did not change with ZnO concentration. On the other hand, viscosity decreased significantly with the first addition of ZnO and then increased slightly with increasing ZnO concentration. Generally, fine (354–464 nm), uniform and beadless nanofibers were obtained. Average fiber diameter, air permeability and water vapor permeability increased with ZnO concentration. EDX analysis results verified the existence of ZnO in the structure of CA nanofibers. As a result of antibacterial studies, it was determined that the CA/zinc oxide (ZnO) composite nanofibers with the highest concentration of ZnO showed very good antibacterial activity against both S. aureus and E. coli bacterial strains."
{"title":"ELECTROSPINNING OF ANTIBACTERIAL CELLULOSE ACETATE NANOFIBERS","authors":"İ.Y. Mol, F. Cengiz Çallıoğlu, Hülya Kesici Güler, E. Sesli Çetin, G. Bilir","doi":"10.35812/cellulosechemtechnol.2023.57.08","DOIUrl":"https://doi.org/10.35812/cellulosechemtechnol.2023.57.08","url":null,"abstract":"\"Herein, it was aimed to achieve antibacterial cellulose acetate (CA) nanofiber production and characterization. Firstly, solution properties, such as viscosity, conductivity and surface tension, were determined. Secondly, CA/zinc oxide (ZnO) composite nanofibers were produced with optimum process parameters via the electrospinning method. Then, the electrospun nanofibers were characterized by SEM, EDX, DSC, TGA, XRD, air permeability and water vapor permeability testing. Lastly, antibacterial activity tests were carried out in accordance with the AATCC100 method, against Staphylococcus aureus (ATCC 25923) and Escherichia coli (ATCC 25922). According to the results, solution conductivity decreased and surface tension did not change with ZnO concentration. On the other hand, viscosity decreased significantly with the first addition of ZnO and then increased slightly with increasing ZnO concentration. Generally, fine (354–464 nm), uniform and beadless nanofibers were obtained. Average fiber diameter, air permeability and water vapor permeability increased with ZnO concentration. EDX analysis results verified the existence of ZnO in the structure of CA nanofibers. As a result of antibacterial studies, it was determined that the CA/zinc oxide (ZnO) composite nanofibers with the highest concentration of ZnO showed very good antibacterial activity against both S. aureus and E. coli bacterial strains.\"","PeriodicalId":10130,"journal":{"name":"Cellulose Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48088568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-28DOI: 10.35812/cellulosechemtechnol.2023.57.10
H. Shokrkar
"The development of a kinetic model for fermentable sugar production is a significant issue due to the complexity of the enzymatic hydrolysis of cellulose. This study presents a proper mathematical model for the evaluation of enzymatic hydrolysis of microalgal cellulose and different cellulosic materials. The modeling results were compared with experimental results of enzymatic hydrolysis of microalgal cellulose and different cellulosic materials. Also, the results of the proposed modified model and another model from the literature were compared. The comparison indicated that the proposed modified model gives a more accurate prediction of the production of glucose, cellobiose, and cellulose consumption as a function of time, during enzymatic hydrolysis of cellulosic materials. The proposed modified model, with an average of equal to 38.15, is more accurate than the previously reported model, with an average of equal to 48.84."
{"title":"MODEL-BASED EVALUATION OF ENZYMATIC HYDROLYSIS OF MICROALGAL CELLULOSE AND DIFFERENT CELLULOSIC MATERIALS","authors":"H. Shokrkar","doi":"10.35812/cellulosechemtechnol.2023.57.10","DOIUrl":"https://doi.org/10.35812/cellulosechemtechnol.2023.57.10","url":null,"abstract":"\"The development of a kinetic model for fermentable sugar production is a significant issue due to the complexity of the enzymatic hydrolysis of cellulose. This study presents a proper mathematical model for the evaluation of enzymatic hydrolysis of microalgal cellulose and different cellulosic materials. The modeling results were compared with experimental results of enzymatic hydrolysis of microalgal cellulose and different cellulosic materials. Also, the results of the proposed modified model and another model from the literature were compared. The comparison indicated that the proposed modified model gives a more accurate prediction of the production of glucose, cellobiose, and cellulose consumption as a function of time, during enzymatic hydrolysis of cellulosic materials. The proposed modified model, with an average of equal to 38.15, is more accurate than the previously reported model, with an average of equal to 48.84.\"","PeriodicalId":10130,"journal":{"name":"Cellulose Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46016436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-28DOI: 10.35812/cellulosechemtechnol.2023.57.15
S. Mohamed, M. Hassan, Essam S. Abd El‐Sayed, M. El-Sakhawy
"This study evaluates the efficiency of nanocomposite films prepared from cellulose nanofibers (CNF) isolated from rice straw and different ratios of shellac in terms of film properties, in addition to using a CNF/shellac mixture for coating paper sheets. The CNF/shellac nanocomposite films were prepared by the casting procedure. The weight percentage of shellac in the composition of the nanocomposite films was varied from 0 to 40%. Scanning electron microscopy was used to show the films’ morphological structure. Also, the films’ air permeability, tensile strength and water vapour permeability (WVP) were investigated. The outcomes showed that adding shellac to CNF can improve the films’ tensile strength, WVP and air permeability characteristics. The formulation chosen for coating paper contained 60% CNF and 40% shellac. Tests were done to assess the tensile and burst strength, water absorption, air permeability and water vapour permeability of coated paper sheets. SEM analysis was performed on the surface and cross-section of coated paper sheets. It was noticed that paper sheets coated with a 90-μm thick film of CNF or CNF/shellac presented enhanced tensile strength, as well as lower water absorption, air permeability and WVP, while the burst strength properties were not affected. The addition of shellac to the composite coating produced coated paper sheets with better tensile strength compared to those of paper sheets coated with CNF alone, making them a viable choice for packaging materials."
{"title":"\"CELLULOSE NANOFIBER/SHELLAC NANOCOMPOSITE FILMS AS COATINGS FOR PACKAGING PAPER\"","authors":"S. Mohamed, M. Hassan, Essam S. Abd El‐Sayed, M. El-Sakhawy","doi":"10.35812/cellulosechemtechnol.2023.57.15","DOIUrl":"https://doi.org/10.35812/cellulosechemtechnol.2023.57.15","url":null,"abstract":"\"This study evaluates the efficiency of nanocomposite films prepared from cellulose nanofibers (CNF) isolated from rice straw and different ratios of shellac in terms of film properties, in addition to using a CNF/shellac mixture for coating paper sheets. The CNF/shellac nanocomposite films were prepared by the casting procedure. The weight percentage of shellac in the composition of the nanocomposite films was varied from 0 to 40%. Scanning electron microscopy was used to show the films’ morphological structure. Also, the films’ air permeability, tensile strength and water vapour permeability (WVP) were investigated. The outcomes showed that adding shellac to CNF can improve the films’ tensile strength, WVP and air permeability characteristics. The formulation chosen for coating paper contained 60% CNF and 40% shellac. Tests were done to assess the tensile and burst strength, water absorption, air permeability and water vapour permeability of coated paper sheets. SEM analysis was performed on the surface and cross-section of coated paper sheets. It was noticed that paper sheets coated with a 90-μm thick film of CNF or CNF/shellac presented enhanced tensile strength, as well as lower water absorption, air permeability and WVP, while the burst strength properties were not affected. The addition of shellac to the composite coating produced coated paper sheets with better tensile strength compared to those of paper sheets coated with CNF alone, making them a viable choice for packaging materials.\"","PeriodicalId":10130,"journal":{"name":"Cellulose Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48837487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-28DOI: 10.35812/cellulosechemtechnol.2023.57.13
Eduardo Leonarski, Giulia VALAR MARTINI, Karina Cesca, M. F. da Silva, Rosana Goldbeck, Patrícia Poletto
"The production of kombucha generates bacterial cellulose (BC) as a by-product, which is usually discarded. However, BC can be a source of cellobiose, a disaccharide with prebiotic benefits. In this study, the yield of cellobiose released from BC collected from a medium-sized kombucha producer was evaluated by enzymatic hydrolysis using the commercial cocktail Celluclast 1.5 L. The BC was hydrolyzed at solid contents of 2, 3 and 4% (m/v), enzyme dosage of 2.2 U/g cellulose, pH 5, 50 °C, and 150 rpm for 72 h. Industrial BC was characterized by FTIR and XRD to confirm the presence of common BC characteristics. The same analyses were performed after enzymatic hydrolysis, resulting in a change in crystallinity. The maximum cellobiose production (10-11 g/L) was obtained with 4% BC (w/v) in 48 h of hydrolysis; there was no significant difference when the time was extended to 72 h. The maximum glucose production under the same conditions was 3 g/L, showing that Celluclast 1.5 L has high cellobiose selectivity (78%). However, the cellobiose yield only ranged from 35 to 26%, indicating that cellobiose accumulation in the medium caused enzyme inhibition."
{"title":"ENZYMATIC UPCYCLING OF BACTERIAL CELLULOSE FROM KOMBUCHA TO OBTAIN CELLOBIOSE","authors":"Eduardo Leonarski, Giulia VALAR MARTINI, Karina Cesca, M. F. da Silva, Rosana Goldbeck, Patrícia Poletto","doi":"10.35812/cellulosechemtechnol.2023.57.13","DOIUrl":"https://doi.org/10.35812/cellulosechemtechnol.2023.57.13","url":null,"abstract":"\"The production of kombucha generates bacterial cellulose (BC) as a by-product, which is usually discarded. However, BC can be a source of cellobiose, a disaccharide with prebiotic benefits. In this study, the yield of cellobiose released from BC collected from a medium-sized kombucha producer was evaluated by enzymatic hydrolysis using the commercial cocktail Celluclast 1.5 L. The BC was hydrolyzed at solid contents of 2, 3 and 4% (m/v), enzyme dosage of 2.2 U/g cellulose, pH 5, 50 °C, and 150 rpm for 72 h. Industrial BC was characterized by FTIR and XRD to confirm the presence of common BC characteristics. The same analyses were performed after enzymatic hydrolysis, resulting in a change in crystallinity. The maximum cellobiose production (10-11 g/L) was obtained with 4% BC (w/v) in 48 h of hydrolysis; there was no significant difference when the time was extended to 72 h. The maximum glucose production under the same conditions was 3 g/L, showing that Celluclast 1.5 L has high cellobiose selectivity (78%). However, the cellobiose yield only ranged from 35 to 26%, indicating that cellobiose accumulation in the medium caused enzyme inhibition.\"","PeriodicalId":10130,"journal":{"name":"Cellulose Chemistry and Technology","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2023-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45578666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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