Search Results (6)

Agricultural activities produce large quantities of organic byproducts and waste rich in lignocellulosic materials, which are not sufficiently utilized. In this study, alternative agricultural waste products, namely, spent mushroom substrate (SMS) from the cultivation of edible Pleurotus ostreatus mushrooms and the roots of leafy vegetables from hydroponic cultivation (HRL), were evaluated for their potential to be used as substrates for the cultivation of Pleurotus citrinopileatus and their effects on the quality, the nutritional value, the chemical properties (lipid, protein, carbohydrate, ash, fatty acid and carbohydrate composition) and the bioactive content (total phenolic compounds and antioxidant activity) of produced mushrooms. SMS and HRL (in different ratios with and without additives) and wheat straw with additives (WS—control) were used. During incubation, the linear growth rate of the mycelium (Kr, mm/day) was measured and used for screening. Mushroom cultivation took place in bags, where several characteristics were examined: earliness (duration between the day of substrate inoculation and the day of first harvest) and biological efficiency (B.E. %, the ratio of the weight of fresh mushrooms produced per dry weight of the substrate × 100). Furthermore, this study aimed to investigate the effect of the protein extract (PE) and carbohydrate extract (CE) of P. citrinopileatus after in vitro digestion (fraction less than 3kDa: PE-DP-3; digestate fraction: CE-D, respectively) on the expression of antioxidant-related genes in the THP-1 cell line. The results showed that mushrooms grown on SMS 50%-HRL 40% had the fastest growth (6.1 mm/d) and the highest protein and lipid contents (34.7% d.w.; 5.1% d.w.). The highest B.E. (73.5%), total carbohydrate (65.7%) and total phenolic compound (60.2 mg GAE/g d.w.) values were recorded on the control substrate. Antioxidant activity was observed in all extracts; the total flavonoid content was low in the samples, and the maximum total triterpene value was detected in SMS 80%-HRL 20% (9.8 mg UA/g d.w.). In all mushrooms, linoleic acid (C18:2) was the main fatty acid (above 60%), and fructose was the dominant individual saccharide. In the investigation of the regulation pathway, NFE2L2 gene expression was upregulated only in the SMS 60%-HRL 40% intervention during incubation with CE-D samples. Additionally, the transcription levels of antioxidant-related genes, SOD1, CAT, HMOX1 and GSR, were increased in the SMS 60–30% intervention. Compared to WS, the alternative substrates are observed to trigger a pathway concerning CE that may resist oxidative stress. This study supports the utilization of agricultural byproducts through sustainable and environmentally friendly practices while simultaneously producing high-value-added products such as mushrooms. Therefore, alternative substrates, particularly those containing HRL, could serve as natural sources of antioxidant potential. Full article

This study reports an innovative approach for producing nanoplastics (NP) from various types of domestic waste plastics without the use of chemicals. The plastic materials used included water bottles, styrofoam plates, milk bottles, centrifuge tubes, to-go food boxes, and plastic bags, comprising polyethylene terephthalate (PET), polystyrene (PS), polypropylene (PP), high-density polyethylene (HDPE), and Poly (Ethylene-co-Methacrylic Acid) (PEMA). The chemical composition of these plastics was confirmed using Raman and FTIR spectroscopy, and they were found to have irregular shapes. The resulting NP particles ranged from 50 to 400 nm in size and demonstrated relative stability when suspended in water. To assess their impact, the study investigated the effects of these NP particulates on cell viability and the expression of genes involved in inflammation and oxidative stress using a macrophage cell line. The findings revealed that all types of NP reduced cell viability in a concentration-dependent manner. Notably, PS, HDPE, and PP induced significant reductions in cell viability at lower concentrations, compared to PEMA and PET. Moreover, exposure to NP led to differential alterations in the expression of inflammatory genes in the macrophage cell line. Overall, this study presents a viable method for producing NP from waste materials that closely resemble real-world NP. Furthermore, the toxicity studies demonstrated distinct cellular responses based on the composition of the NP, shedding light on the potential environmental and health impacts of these particles. Full article

The depletion of natural resources and greenhouse gas emissions related to the manufacture and use of ordinary Portland cement (OPC) pose serious concerns to the environment and human life. The present research focuses on using alternative binders to replace OPC. Geopolymer might be the best option because it requires waste materials enriched in aluminosilicate for its production. The research on geopolymer concrete (GPC) is growing rapidly. However, substantial effort and expenses are required to cast specimens, cures, and tests. Applying novel techniques for the said purpose is the key requirement for rapid and cost-effective research. In this research, supervised machine learning (SML) techniques, including two individual (decision tree (DT) and gene expression programming (GEP)) and two ensembled (bagging regressor (BR) and random forest (RF)) algorithms were employed to estimate the compressive strength (CS) of GPC. The validity and comparison of all the models were made using the coefficient of determination (R²), k-fold, and statistical assessments. It was noticed that the ensembled SML techniques performed better than the individual SML techniques in forecasting the CS of GPC. However, individual SML model results were also in the reasonable range. The R² value for BR, RF, GEP, and DT models was 0.96, 0.95, 0.93, and 0.88, respectively. The models’ lower error values such as mean absolute error (MAE) and root mean square errors (RMSE) also verified the higher precision of ensemble SML methods. The RF (MAE = 2.585 MPa, RMSE = 3.702 MPa) and BR (MAE = 2.044 MPa, RMSE = 3.180) results are better than the DT (MAE = 4.136 MPa, RMSE = 6.256 MPa) and GEP (MAE = 3.102 MPa, RMSE = 4.049 MPa). The application of SML techniques will benefit the construction sector with fast and cost-effective methods for estimating the properties of materials. Full article

The application of waste materials in concrete is gaining more popularity for sustainable development. The adaptation of this approach not only reduces the environmental risks but also fulfills the requirement of concrete material. This study used the novel algorithms of machine learning (ML) to forecast the splitting tensile strength (STS) of concrete containing recycled aggregate (RA). The gene expression programming (GEP), artificial neural network (ANN), and bagging techniques were investigated for the selected database. Results reveal that the precision level of the bagging model is more accurate toward the prediction of STS of RA-based concrete as opposed to GEP and ANN models. The high value (0.95) of the coefficient of determination (R²) and lesser values of the errors (MAE, MSE, RMSE) were a clear indication of the accurate precision of the bagging model. Moreover, the statistical checks and k-fold cross-validation method were also incorporated to confirm the validity of the employed model. In addition, sensitivity analysis was also carried out to know the contribution level of each parameter toward the prediction of the outcome. The application of ML approaches for the anticipation of concrete’s mechanical properties will benefit the area of civil engineering by saving time, effort, and resources. Full article

The article presents the results of research aimed at analysing the share of fractions suitable for recycling and pollutants in waste collected in a yellow bag. The research was carried out in an area inhabited by 200,000 people. The amount of waste collected in the communes in yellow containers in 2016–2019 increased systematically in communes: rural by 75.8, urban–rural by 44.9 and urban by 17.8%. The collection efficiency expressed in the degree of collection was the highest and grew fastest in rural areas (from 25.1 to 35.5%). In cities, it practically did not change (14.4–15.8%). The weight of recyclable components represented on average 39.9% of the weight of yellow bag waste. Plastic bottles (PET) packaging prevailed, the share of which changed from 19.6 to 14.8%, including the share of colourless PET decreasing from 7.9 to 5.8%. At present, revenue from the sale of secondary raw materials obtained from waste collected separately to yellow bags covers only 26% of the costs related to the recycling and recovery of waste delivered to the installation. Support for separate collection of plastics through recovery organisations, i.e., entrepreneurs who are obliged to recover and recycle waste, is symbolic. Full article

With the rapid development of China’s e-commerce and logistics industry, a large number of waste express bags (WEBs) have been produced, which are difficult to recycle. The existing methods of waste express bag disposal often cause severe environmental pollution. It was discovered in this paper that the use of WEBs to modify bitumen could be an environmentally friendly way to recycle WEBs. This study aimed to investigate the feasibility of using WEBs to modify bitumen and promote the performance of WEB-modified bitumen. In order to verify this assumption, a series of basic or rheological experiments were conducted on different dosages of WEB-modified bitumen. The test results and phenomenon showed that the WEBs could be used to modify the binder homogeneously by using a high-speed shearing machine. The basic experiments showed that the WEBs could decrease the penetration and ductility while increasing the softening point and the rotational viscosity. Additionally, the rheological experimental data indicated that the high temperature performance was improved while the low temperature performance stayed the same. The Fourier-transform infrared spectroscopy (FTIR) results demonstrated that modification of the WEB was a physical modification without chemical reaction and the main component of the modifier was polyethylene. The fluorescence microscope (FM) data revealed the micro-structures of different dosages of WEB-modified bitumen. In conclusion, WEB can be a feasible binder modifier. Full article