Waste from the fishing industry is disposed of in soils and oceans, causing environmental damage. However, it is also a source of valuable compounds such as chitin. Although chitin is the second most abundant polymer in nature, its use in industry is limited due to the lack of standardized and scalable extraction methods and its poor solubility. The deacetylation process increases its potential applications by enabling the recovery of chitosan, which is soluble in dilute acidic solutions. Chitosan is a polymer of great importance due to its biocompatible and bioactive properties, which include antimicrobial and antioxidant capabilities. Chitin extraction and its deacetylation to obtain chitosan are typically performed using chemical processes that involve large amounts of strongly acidic and alkaline solutions. To reduce the environmental impact of this process, extraction methods based on biotechnological tools, such as fermentation and chitin deacetylase, as well as emerging technologies, have been proposed. These extraction methods have demonstrated the potential to reduce or even avoid using strong solvents and shorten extraction time, thereby reducing costs. Nevertheless, it is important to address existing gaps in this area, such as the requirements for large-scale implementation and the determination of the stoichiometric ratios for each process. This review highlights the use of biotechnological tools and emerging technologies for chitin extraction and chitosan production. These approaches truly minimize environmental impact, reduce the use of strong solvents, and shorten extraction time. They are a reliable alternative to fishery waste valorization, lowering costs; however, addressing the critical gaps for their large-scale implementation remains challenging.

Pulp and paper mill sludge is composed of cellulosic waste and clay and is rich in microorganisms that can benefit horticulture. However, its application in horticulture has received less research attention. Field and greenhouse studies were carried out to determine if sludge from a case study industry can replace the typical cellulosic additive utilized in hydroseeding, and the ideal application rate of a sludge-soil-seed mixture. The treatments were 0-100% sludge and soil by mass with a consistent mass of embedded seeds of Kentucky Bluegrass (Poa pratensis), Creeping Red Fescue (Festuca rubra), Perennial (Lolium perenne) and Annual Ryegrass (Lolium multiflorum). Seeding with a top layer of soil and 5 to 75% sludge gave the best outcome using a cellulosic additive after 3 weeks of growth. Mixtures containing 5-25% sludge resulted in the quickest seed germination rate. The cellulosic additive has the capacity to retain a higher volume of water but requires 15 times more material by volume. An increase in sludge increased water retention by 20%. Overall, the cellulosic additive in hydroseeding applications can be replaced by sludge without plant detriment. However, further testing is needed to determine long-term effects. [GRAPHICS] .

There is an increasing demand for sustainable construction materials to address the challenges posed by the environmental impact of the built environment (BE), which is driven by climate change, population growth, and urbanization. Conventional construction materials like cement contribute significantly to carbon emissions during production, transport, use, and disposal phases, and their poor thermal conductivity hinders efforts to maintain comfortable indoor environments. To address these challenges, there is an urgent need for innovative, locally sourced thermal insulation materials specifically designed for regions with extreme climates and high energy demands to maintain building comfort. This research explores synthesizing novel, environmentally friendly building materials using locally sourced date palm fiber waste and clay. The study also investigates the developed material's 3D printing (3DP) capabilities and optimizes its printing parameters with lab-scale prototypes. Additionally, thermo-mechanical characterization is conducted to assess its suitability for built environment applications. Different concentrations, from 1 to 5 wt% of date palm fiber to clay ratio (Dpf/C), were studied regarding microstructural, thermal, and mechanical properties, dimensional accuracy, and feasibility for 3DP of BE structures. Results demonstrated a significant reduction in thermal conductivity by 73%, achieving 0.244 W/mK, and an increase in compressive strength by 106%, reaching 10.9 MPa at 5 wt% Dpf/C. The promising thermomechanical properties of these composites and their suitability for 3DP support their use in real-world applications in the future's sustainable built environment. This scalable methodology can be adapted to regions with similar sustainable local and waste resources, advancing the circular economy.

Plastic pots used in horticultural nurseries generate substantial waste, causing environmental pollution. This study aimed to develop biodegradable composites from banana pseudo-stem reinforced with agricultural residues like pineapple leaves, taro and water hyacinth as eco-friendly substitutes. The aim of this study is to develop optimised banana biocomposite formulations with suitable reinforcements that balance mechanical durability, biodegradation, and seedling growth promotion properties to serve as viable eco-friendly alternatives to plastic seedling pots. This study was carried out by fabricating banana fibre mats through pulping, drying and hot pressing. Composite sheets were reinforced with 50 % pineapple, taro or water hyacinth fibres. The mechanical properties (tensile, yield strength, elongation, bursting strength), hydrophilicity (contact angle, water absorption), biodegradability (soil burial test), and seedling growth promotion were evaluated through appropriate testing methods. The results show that banana-taro composites exhibited suitable tensile strength (25 MPa), elongation (27 %), water uptake (41 %) and 82 % biodegradation in 60 days. It was observed that biodegradable seedling trays fabricated from banana-taro composite showed 95 % tomato seed germination and a 125 cm plant height increase in 30 days, superior to plastic trays. The finding shows that the study demonstrates the potential of banana-taro biocomposites as alternatives to plastic nursery pots, enabling healthy seedling growth while eliminating plastic waste pollution through biodegradation.

The development of sustainable materials from the valorization of waste is a good alternative to reducing the negative environmental impact of plastic packaging. The objectives of this study were to develop and characterize pectin-based composite films incorporated with cork or cork with either coffee grounds or walnut shells, as well as to test the films' genotoxicity, antioxidant properties, and biodegradation capacity in soil and seawater. The addition of cork, coffee grounds, or walnut shells modified the films' characteristics. The results showed that those films were thicker (0.487 +/- 0.014 mm to 0.572 +/- 0.014 mm), more opaque (around 100%), darker (L* = 25.30 +/- 0.78 to 33.93 +/- 0.84), and had a higher total phenolic content (3.17 +/- 0.01 mg GA/g to 4.24 +/- 0.02 mg GA/g). On the other hand, the films incorporated only with cork showed higher values of elongation at break (32.24 +/- 1.88% to 36.30 +/- 3.25%) but lower tensile strength (0.91 +/- 0.19 MPa to 1.09 +/- 0.08 MPa). All the films presented more heterogeneous and rougher microstructures than the pectin film. This study also revealed that the developed films do not contain DNA-reactive substances and that they are biodegradable in soil and seawater. These positive properties could subsequently make the developed films an interesting eco-friendly food packaging solution that contributes to the valorization of organic waste and by-products, thus promoting the circular economy and reducing the environmental impact of plastic materials.