Trends on the cellulose-based textiles: raw materials and technologies

There is an emerging environmental awareness and social concern regarding the environmental impact of the textile industry, highlighting the growing need for developing green and sustainable approaches throughout this industrys supply chain. Upstream, due to population growth and the rise in consumption of textile fibers, new sustainable raw materials and processes must be found. Cellulose presents unique structural features, being the most important and available renewable resource for textiles. The physical and chemical modification reactions yielding fibers are of high commercial importance today. Recently developed technologies allow the production of filaments with the strongest tensile performance without dissolution or any other harmful and complex chemical processes. Fibers without solvents are thus on the verge of commercialization. In this review, the technologies for the production of cellulose-based textiles, their surface modification and the recent trends on sustainable cellulose sources, such as bacterial nanocellulose, are discussed. The life cycle assessment of several cellulose fiber production methods is also discussed.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684) and BioTecNorte Operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020– Programa Operacional Regional do Norte. Support from The Navigator Company through the I&D n◦ 21874, “Inpactus– Produtos e Tecnologias Inovadores a partir do Eucalipto,” funded through the Fundo Europeu de Desenvolvimento Regional (FEDER) and the Programa Operacional Competitividade e Internacionalização (POCI) is acknowledged.info:eu-repo/semantics/publishedVersio

Regenerated bacterial cellulose fibres

The global shortage of cotton for textile production, forces the exploitation of forests´ lignocellulosic biomass to produce man-made cellulosic fibres (MMCF). This has a considerable environmental impact, pressing the textile industry to search for new sustainable materials and to the development of sustainable recycling processes. Bacterial cellulose (BC), an exopolysaccharide produced by fermentation, could represent such an alternative. In particular, we tested the possibility of improving the mechanical properties of cellulose filaments with a low degree of polymerization (DP) by combining them with high DP from BC, so far exploited to little extent in the textile field. In this work, BC with different degrees of polymerization (DPcuaxam) (BCneat: 927; BCdep:634 and BCblend: 814) were dissolved in N-methylmorpholine-N-oxide (NMMO) and their spinnability was studied. The rheological behaviour of the dopes was assessed and all were found to be spinnable, at suitable concentrations (BCneat:9.0%; BCdep:12.2%; BCblend:10.5%). A continuous spinning was obtained and the resulting filaments offered similar mechanical performance to those of Lyocell. Further, the blending of BC pulps with different DPs (BCblend, obtained by combining BCneat and BCdep) allowed the production of fibres with higher stiffness (breaking tenacity 56.4 CN.tex1) and lower elongation (8.29%), as compared to samples with more homogeneous size distribution (neat BC and depolymerized BC).info:eu-repo/semantics/publishedVersio

Nanocellulose bio-based composites for food packaging

The food industry is increasingly demanding advanced and eco-friendly sustainable packaging materials with improved physical, mechanical and barrier properties. The currently used materials are synthetic and non-degradable, therefore raising environmental concerns. Consequently, research efforts have been made in recent years towards the development of bio-based sustainable packaging materials. In this review, the potential of nanocelluloses as nanofillers or as coatings for the development of bio-based nanocomposites is discussed, namely: (i) the physico-chemical interaction of nanocellulose with the adjacent polymeric phase, (ii) the effect of nanocellulose modification/functionalization on the final properties of the composites, (iii) the production methods for such composites, and (iv) the effect of nanocellulose on the overall migration, toxicity, and the potential risk to human health. Lastly, the technology readiness level of nanocellulose and nanocellulose based composites for the market of food packaging is discussed.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte.” The authors also acknowledge the financial support of the FCT (ESF) through the grant given to Francisco A.G.S. Silva (SFRH/BD/146375/2019).info:eu-repo/semantics/publishedVersio

Development of bacterial cellulose composites for food packaging and textiles

Most of all petroleum-based materials are used for a short period of time but then take centuries to degrade. Food packaging and textile are examples of industries that are truly dependent of synthetic materials. Therefore, there is an increasing interest on seeking alternatives to these materials. Plant nanocellulose (PNC) has been actively studied, yet the high demand may arise environmental issues such deforestation and wood processing. An alternative source is bacterial cellulose (BC), produced by bacteria of the genus Komagataeibacter, through fermentation. BC has a great potential due to great mechanical performance, despite some drawbacks such high water affinity (for food packaging) and high molecular weight (for textiles). Different approaches were used with the attempt to reduce water vapor permeability and functionalize BC based composite for Food packaging. For textiles, highly performing fibres were developed after using adapted Lyocell and Ioncell technologies.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit, BIOPROTECT - Development of Biodegradable Packaging Material with Active Properties for Food Preservation POCI-01-0247-FEDER-069858, COMPETE 2020 (POCI-01-0145-FEDER-006684) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional DevelopmentFund under the scope of Norte2020 - Programa Operacional Regional do Norte.” The authors also acknowledge the financial support of the FCT (ESF) through the grant given to Francisco A.G.S. Silva (SFRH/BD/146375/2019). The authors also thank all the support given by the Thuringian Institute for Textile and Plastics Research (TITK) and the department of Bioproducts and Biosystems at Aalto University. The authors also thank the support of Aquitex - Acabamentos Químicos Têxteis, S.A.info:eu-repo/semantics/publishedVersio

Study and valorisation of wastewaters generated in the production of bacterial nanocellulose

[Excerpt] The use of low-cost residues from the agro-food industries in the formulation of fermentation culture media is often claimed to represent a strategy to reduce the production cost Bacterial NanoCellulose (BNC). However, the impact of such culture media, e.g. made of molasse and corn steep liquor, on the organic load of the wastewaters generated in this process has never been assessed. This work aims to characterize the wastewaters resulting from the fermentation of BNC using different culture media, under static culture, as well as their biochemical methane potential (BMP) and anaerobic biodegradability. Anaerobic digestion (AD) is one of the most promising treatments for industrial wastewaters with high organic loads since, beyond removal of the organic matter, it generates energy in form of biogas. Two wastewaters streams were analysed: i) the one collected from the culture medium after fermentation (WaF); ii) the one that, in addition to the previous, includes the BNC washing wastewaters (WaW). The performance of an upflow anaerobic sludge blanket reactor (UASB) for the treatment of the later (WaW) was also evaluated. [...]info:eu-repo/semantics/publishedVersio

Optimization of bacterial nanocellulose fermentation using lignocellulosic residues and development of novel BNC-starch composites

In papermaking industry, significant fraction of fibres that cannot be re-utilized are wasted, which raise economic and environmental concerns[1]. On the other hand, development of renewable polymeric materials became a priority for the sustainability of several industries. Bacterial nanocellulose (BNC), a biopolymer extruded by Gluconacetobacter xylinus as a 3D nanofibrillar network, provide interesting properties as high porosity, high water retention, biocompatibility, non-toxicity and biodegradability [2]. These properties have sustained promising applications in the biomedical field, papermaking, composites and foods. However, large-scale BNC production remains a challenge, due to ineffective fermentation systems and high operating costs [2-3]. Therefore, the production of BNC through lignocellulosic residues has been studied. Recycled-paper-sludge (RPS) composed of small fibres with 40% of carbohydrates were hydrolysed and used as a carbon source in culture media formulation. Then, a Response Surface Methodology (RSM) optimization with RPS was assessed in order to maximize BNC production, through static fermentation with K. hansenii ATCC 53582. Overall, the results suggest that RPS had potential to be an alternative carbon source for BNC production with a maximum BNC yield of 5 g/L. BNC produced as described above was then used for the development of novel green thermoplastic nanocomposites, combined with starch. When mixed with water and glycerol (with heat and shear), starch undergoes spontaneous destructuring, forming thermoplastic starch (TPS). In particular to food packaging applications, BNC has remained unexploited in spite of being considered to have enormous potential [4-5]. In this work, two approaches for composite production were assessed. Firstly, BNC 3D membrane was filled with biodegradable bio-based thermoplastic starch (TPS), where the production was achieved in a two-step process: impregnation of TPS in the BNC membrane, followed by drying. Different thicknesses of BNC membrane were studied (1-5 mm) as two impregnation time (24h;72h). The second approach consisted on the use of glycerol-TPS as matrix, where different concentrations (0.05 -0.5% w/v) of cellulose (Plant (PC) and BNC) was added. TPS-BNC and TPS-PC films were prepared by solution casting method. All nanocomposites manufactured were then characterized in terms of mechanical properties, morphology and permeability to water vapor (WVT). Overall, enhanced mechanical and barrier properties were obtained with BNC-TPS composites. In comparison to TPS-BNC and TPS-PC films, higher young modulus and tensile strength was obtained with the BNC-TPS composites. Being longer andinfo:eu-repo/semantics/publishedVersio

Bacterial cellulose as a novel stabilizer and texturizer for cosmetic and food applications

Book of Abstracts of CEB Annual Meeting 2017[Excerpt] Bacterial nanocellulose (BNC) is a sophisticated material produced biotechnologically by different microorganisms, but most efficiently by acetic acid bacteria from the genera Gluconacetobacter. While chemically identical to plant cellulose, BNC is chemically pure. Each BNC nanofiber is a bundle of cellulose nanofibrils. Due to their nano-size, these aggregates of extended cellulose chains have a rather large surface area. The unique properties of BNC account for an extraordinary physico-chemical and mechanical behaviour. For industrial applications, hydrocolloidal microcrystalline cellulose from vegetable sources is widely used to regulate the texture, rheology, stability and organoleptic properties of the formulations [1]. Several studies are being carried out to investigate the technological role of BNC. Preliminary results already showed that BNC is technically superior to these vegetable celluloses, and can outperform plant celluloses in several applications within the food industry. As a novel hydrocolloid, BNC presents important features such as the stabilization of heterogeneous systems (air-liquid, solid-liquid and liquidliquid): it is able to stabilize aerogels, increasing the incorporation of air in the liquid matrix (overrun), so it can be used as an additive in ice cream, smoothies and whipped cream; it can stabilize solid particles in a liquid matrix (e.g. cocoa particles in chocolate milk); BNC also stabilizes of oil-in-water emulsions, in spoonable and pourable dressings, without the need to add any other emulsifying agents. [...]info:eu-repo/semantics/publishedVersio

Convexity in partial cubes: the hull number

We prove that the combinatorial optimization problem of determining the hull number of a partial cube is NP-complete. This makes partial cubes the minimal graph class for which NP-completeness of this problem is known and improves some earlier results in the literature. On the other hand we provide a polynomial-time algorithm to determine the hull number of planar partial cube quadrangulations. Instances of the hull number problem for partial cubes described include poset dimension and hitting sets for interiors of curves in the plane. To obtain the above results, we investigate convexity in partial cubes and characterize these graphs in terms of their lattice of convex subgraphs, improving a theorem of Handa. Furthermore we provide a topological representation theorem for planar partial cubes, generalizing a result of Fukuda and Handa about rank three oriented matroids.Comment: 19 pages, 4 figure

Effect of guar gum on the physicochemical, thermal, rheological and textural properties of green edam cheese

In attempts to produce a low-fat cheese with a rheology and texture similar to that of a full-fat cheese, guar gum (within 0.0025–0.01%; w/v, final concentration) was added to low-fat milk. The obtained cheeses were characterised regarding their physicochemical, thermal, rheological and textural properties. Control cheeses were also produced with low and full-fat milk. The physicochemical properties of the guar gum modified cheeses were similar to those of the low-fat control. No significant differences were detected in the thermal properties (concerning the enthalpy and profile of water desorption) among all types of cheeses. The rheological behaviour of the 0.0025% modified cheese was very similar to the full-fat control. Overall, no trend was observed in the texture profile (hardness, cohesiveness, gumminess and elasticity) of the modified cheeses versus guar gum concentration, as well as in comparison with the control groups, suggesting that none of the studied polysaccharide concentrations simulated the textural functions of fat in Edam cheese

On to the impact of low cost substrates for BNC production

Bacterial nanocellulose (BNC) is an exopolysaccharide produced by certain acetic acid bacteria. It has high crystallinity, high mechanical strength, high purity and high water-holding capacity. These properties make it useful in making artificial skin (1), electronic paper, composite reinforcement, development of food and cosmetic applications (2). The cost of fermentation media is believed to contribute significantly to the operational costs, especially if synthetic commercial media are used. Hence, much research on BNC production using low-cost substrates has been done focusing on lowering the production costs (3). Also, to meet the requirement for industrial applications, effective large-scale BNC production systems need to be developed, which involves improving the fermentation conditions and identifying high yield BNC-producing strains (4). However, as with many fermentation systems, while promoting the recycling of low value-added products, the use of complex substrates may in fact represent a bottleneck in the BNC fermentation processes. Some of these substrates present, comparatively to synthetic nutrients, high chemical oxygen demand (COD), total and volatile solids (TS and VS), total nitrogen (TN), antimicrobial components (such as phenols) Consequently, these alternative substrates may place an economic problem either downhill, due to the need for wastewaters treatments and/or, uphill, due to the need of substrates pre-treatment. In this work, the optimization of alternative BNC culture medium (Molasses-Corn Steep Liquor, MOL-CSL), using Response surface methodology central composite design was used to evaluate the effect of inexpensive and widely available nutrients sources, namely MOL, ethanol (EtOH), CSL and ammonium sulphate on BNC production yield under static culture by komagataeibacter xylinus BPR 2001. The optimized parameters for maximum BNC production were: % (m/v): MOL 5.38, CSL 1.91, ammonium sulphate 0.63, disodium phosphate 0.270, citric acid 0.115 and ethanol 1.38 % (v/v). The maximum BNC production yield were 7.5 ± 0.54 g/L versus 1.79 ± 0.04 g/L for MOL-CSL and synthetic medium (HS-EtOH) culture medium, respectively. The resulting wastewater from each culture medium was characterized regarding COD, TN, TS and VS, leading to the conclusion that the wastewaters generated using MOL-CSL are more heavily charged with organic matter, increasing the final costs of BNC production due to the higher costs associated to wastewater treatment. Anaerobic digestion (AD) was studied for wastewater treatment and biogas production from the wastewaters of the BNC fermentation and purification process. Finally, a preliminary Life Cycle Assessment of BNC production was performed and will be presented.info:eu-repo/semantics/publishedVersio