Lignocellulosic fibres from enzyme-treated tomato plants: Characterisation and application in paperboard manufacturing

Extraction of high-quality moso bamboo fibers by enzyme/alkali synergistic mechanism

As an emerging non-wood resource, moso bamboo has attracted extensive attention because of its short growth cycle and high holocellulose content. However, the internal structure of moso bamboo is more compact than that of wood, leading to higher chemical consumption during the pulping process, which greatly reduces the quality of the extracted fibers. Herein, an innovative pulping system including enzymes and alkali is proposed to achieve higher-quality extraction of moso bamboo fibers. Benefiting from the synergistic effects of high-temperature and alkali-resistant cellulase, xylanase, and laccase, supplemented with alkaline pulping, adequate retention and softening of moso bamboo fibers were ultimately achieved. The sample treated with an enzyme/alkali system resulted in a relative increase in fiber length of 7.19 % and a 31.26 % increase in beating efficiency over alkaline pulping. In addition, the tensile index and tearing index of the paper treated with the enzyme/alkali system reached 50.17 N·m·g-1 and 9.12 mN·m2·g-1, which were 22.52 % and 20.53 % higher than those of the alkaline pulping, respectively. This work provides new insights into the production of high-performance moso bamboo fibers and paper with low energy and alkali consumption.

Improving agricultural sustainability - A review of strategies to valorize tomato plant residues (TPR)

Considerations for the modification of agricultural practices and waste management to improve environmental sustainability remain a subject of great importance. Prioritization of intensive mass food production to meet the demand of an increasing human population has introduced a multitude of environmental issues due to, among other factors, the large volumes of waste output. Tomato production in greenhouses, for example, generates tonnes of bio-waste per hectare each harvest including green tomato plant residues (i.e., stems, leaves, branches). Giving value to these green tomato plant residues collected during the growing cycle and after harvest has not proven straightforward despite a massive yearly release of tonnes of carbon dioxide from stems and leaves disposed on landfills. This paper aims to summarize current research in tomato plant residue valorization and to identify considerations for future valorization strategies. Peer reviewed articles, scientific books and governmental, economic and statistical reports on the topic of tomato plant residues were collected and analyzed. Focuses included traditional valorization approaches, bio-refinement strategies and conversion of fiber-rich residues into high value packaging materials. Initiatives for sustainable agriculture, their market relevance, and the strengths and weaknesses of using tomato plant residues in these valorization approaches are discussed. Overall, it was concluded that valorization of tomato plant residues would be a highly integrative endeavor that would require coordination from multiple levels in the agricultural production chain.

Replacing maize silage with hydroponic barley forage in lactating water buffalo diet: impact on milk yield and composition, water and energy footprint, and economics

This study investigated the feasibility of integrating hydroponic barley forage (HBF) production into dairy ruminant production, focusing on its effect on milk yield and components, energy and water footprints, and economic implications. Maize silage (MS) was used as a benchmark for comparison. The research was conducted on a water buffalo dairy farm equipped with a fully automated hydroponic system producing approximately 6,000 kg/d of HBF as fed (up 1,000 kg/d on DM basis). Thirty-three lactating water buffaloes were assigned to 3 dietary treatments based on the level of MS or HBF in the diet: D0 (100% MS), D50 (50% MS and 50% HBF), and D100 (100% HBF). The feeding trial lasted 5 weeks plus a 2-week adaptation period during which each cow underwent a weighing, BCS scoring, recording of milk yield and components, including somatic cell count and coagulation characteristics. Based on the data obtained from the in vivo study, the water and energy footprints for the production of MS and HBF and buffalo milk, as well as income over feed cost, were evaluated. Complete replacement of MS with HBF resulted in a slight increase in milk yield without significant impact on milk component. The resource footprint analysis showed potential benefits associated with HBF in terms of water consumption. However, the energy footprint assessment showed that the energy ratio of HBF was less than 1 (0.88) compared with 11.89 for MS. This affected the energy efficiency of milk yield in the 3 diets, with the D50 diet showing poorer performance due to similar milk yield compared with D0, but higher energy costs due to the inclusion of HBF. The production cost of HBF was about 4 times higher than that of farm-produced MS, making feed costs for milk yield more expensive. Nevertheless, HBF can potentially improve income over feed costs if it increases milk yield enough to offset its higher production costs. Overall, the results suggest that the current practice of using HBF to replace high quality feedstuffs as concentrates is likely to result in energy and economic losses.

Investigation of the effect of enzymatic and alkali treatments on the physico-chemical properties of Sambucus ebulus L. plant fiber

The investigation aims to determine the effect of enzymatic and alkali treatments on Sambucus ebulus L. stem fiber. For this purpose, Sambucus ebulus L. stem fibers were treated with alkali, cellulase, and pectinase enzymes. An image processing technique was developed and implemented to calculate the average thicknesses of Sambucus ebulus L. fibers. The thickness of alkali, cellulase and pectinase enzyme treated fibers was determined as 478.62 μm, 808.28 μm and 478.20 μm, respectively. Scanning electron microscopy analysis illustrated that enzymatic and alkali treatments lead to the breakage of fiber structure. Furthermore, enzymatic and alkali treatments induce variations in elemental ingredients. All treatments increased the crystallinity index of Sambucus ebulus L. fiber from 72 % (raw fiber) to 83 % (alkali treated), 75.2 % (cellulase enzyme treated) and 86.3 % (pectinase enzyme treated) due to the hydrolysis of hemicellulose. Fourier transform infrared analysis indicated that there are no significant differences in functional groups. Thermogravimetric analysis shows that enzymatic and alkali treatments improve final degradation temperature of the fiber. Mechanical behaviors of cellulase enzyme-treated fiber decrease compared to raw fiber, while pectinase enzyme and alkali treatment cause to improve mechanical properties. Tensile strength of samples was determined as 76.4 MPa (cellulase enzyme treated fiber), 210 MPa (pectinase enzyme treated fiber) and 240 MPa (alkali treated fiber). Young's modules of cellulase enzyme, pectinase enzyme and alkali treated fibers were predicted as 5.5 GPa, 13.1 GPa and 16.6 GPa. Elongation at break of samples was calculated as 5.5 % (cellulase enzyme treated fiber), 6.5 % (pectinase enzyme treated fiber) and 6 % (alkali treated fiber). The results suggest that enzymatic and alkali treatments can modify the functional and structural attributes of Sambucus ebulus L. fiber.

Adsorption modeling of microcrystalline cellulose for pharmaceutical-based micropollutants

Cellulose can be considered as a raw material for the production of filters and adsorbents for the removal of micropollutants, particularly in pharmaceutical-based products. To study its applications, it is important to estimate the adsorptive interaction of cellulose with the targeted chemicals, and develop predictive models for the expandable estimation into various types of micropollutants. Therefore, the adsorption affinity between cellulose and micropollutants was measured through isotherm experiments, and a quantitative structure-adsorption relationship model was developed using the linear free energy relationship (LFER) equation. The results indicate that microcrystalline cellulose has a remarkably high adsorption affinity with cationic micropollutants. Moreover, it has interactions with neutral and anionic micropollutants, although they have relatively lower affinities than those of cations. Through a modeling study, an LFER model - comprising of excess molar refraction, polar interaction, molecular volume, and charge-related terms - was developed, which could be used to predict the adsorption affinity values with an R² of 0.895. To verify the robustness and predictability of the model, internal and external validation studies were performed. The results proved that the model was reasonable and acceptable, with an SE = 0.207 log unit.

Study of new reinforcing materials for cementitious panel production

The development of building materials using new types of raw materials is currently on demand by society and the industry. It is intended to reduce production costs, improve properties and obtain ever-increasingly sustainable processes and products. In this respect, this work aimed to evaluate the effect of new types of reinforcement material on the physical-mechanical and thermal properties of cement-based panels. Cement-based panels reinforced with pine wood, coffee husk waste, rice husk and polyethylene terephthalate (PET) were evaluated. The panels were produced with 1.30 g.cm^-3nominal density; 1:2.5 reinforcement material: cement ratio; 1:1.5 water:cement ratio; 0.25 cement hydration rate using Portland ARI V cement and 3% calcium chloride (CaCl₂) as additive. The panels' physical, mechanical and thermal properties were evaluated before and after accelerated aging. PET bottle wastes showed great potential for use in cement-based panel production, obtaining the best physical and mechanical results, and showing superior performance to pine wood panels. Cement-based panels reinforced with coffee husk and rice husk waste obtained lower physical-mechanical performance, presenting usage limitations, however, with the lowest values of thermal conductivity.

Horticultural Plant Residues as New Source for Lignocellulose Nanofibers Isolation: Application on the Recycling Paperboard Process

Horticultural plant residues (tomato, pepper, and eggplant) were identified as new sources for lignocellulose nanofibers (LCNF). Cellulosic pulp was obtained from the different plant residues using an environmentally friendly process, energy-sustainable, simple, and with low-chemical reagent consumption. The chemical composition of the obtained pulps was analyzed in order to study its influence in the nanofibrillation process. Cellulosic fibers were subjected to two different pretreatments, mechanical and TEMPO(2,2,6,6-Tetramethyl-piperidin-1-oxyl)-mediated oxidation, followed by high-pressure homogenization to produce different lignocellulose nanofibers. Then, LCNF were deeply characterized in terms of nanofibrillation yield, cationic demand, carboxyl content, morphology, crystallinity, and thermal stability. The suitability of each raw material to produce lignocellulose nanofibers was analyzed from the point of view of each pretreatment. TEMPO-mediated oxidation was identified as a more effective pretreatment to produce LCNF, however, it produces a decrease in the thermal stability of the LCNF. The different LCNF were added as reinforcing agent on recycled paperboard and compared with the improving produced by the industrial mechanical beating. The analysis of the papersheets’ mechanical properties shows that the addition of LCNF as a reinforcing agent in the paperboard recycling process is a viable alternative to mechanical beating, achieving greater reinforcing effect and increasing the products’ life cycles.