Antimicrobial activity and chemical profile of wood vinegar from eucalyptus (Eucalyptus urophylla x Eucalyptus grandis - clone I144) and bamboo (Bambusa vulgaris).

Microbial resistance to drugs is a public health problem; therefore, there is a search for alternatives to replace conventional products with natural agents. One of the potential antimicrobial agents is wood vinegar derived from the carbonization of lignocellulosic raw materials. The objectives of the present work were to evaluate the antibacterial and antifungal action of two kinds of wood vinegar (WV), one of Eucalyptus urograndis wood and another of Bambusa vulgaris biomass, and determine their chemical profile. The antimicrobial effect was assessed against Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella enteritidis, Escherichia coli, Streptococcus agalactiae, and Candida albicans. The minimum inhibitory concentration and the minimum bactericidal and fungicidal concentrations were determined. Micrographs of the microorganisms before and after exposure to both kinds of wood vinegar were obtained by scanning electron microscopy. The chemical profile of the eucalyptus and bamboo vinegar was carried out by gas chromatography and mass spectrometry (GC/MS). Both types of WV presented significant antimicrobial activity, with the bamboo one having a higher efficiency. Both studied pyroligneous extracts seem promising for developing natural antimicrobials due to their efficiency against pathogens. GC/MS analyses demonstrated that the chemical profiles of both kinds of WV were similar but with some significant differences. The major component of the eucalyptus vinegar was furfural (17.2%), while the bamboo WV was phenol (15.3%). Several compounds in both WVs have proven antimicrobial activity, such as acetic acid, furfural, phenol, cresols, guaiacol, and xylenols. Together, they are the major in the chemical composition of the organic fraction of both WVs. Bamboo vinegar had a more expressive content of organic acids. Micrographs of microorganisms taken after exposure to both kinds of wood vinegar displayed several cell modifications. The potential of both types of wood vinegar as a basis for natural antimicrobial products seems feasible due to their proven effect on inhibiting the microorganisms' growth assessed in this experiment.

Eco-friendly particleboard production from coconut waste valorization.

Reusing agro-industrial waste does not only help to mitigate environmental impact but also enables valorization through the development of new products. The aim is to enhance the physical and mechanical properties of particleboard panels produced with Eucalyptus wood and different proportions of waste products-coconut fiber (Cocos nucifera L.). Physical properties (density, water absorption, and thickness swelling) and mechanical properties (static bending and internal bond resistance) were assessed, and panels reinforced with coconut fiber showed the best qualities with higher density, greater dimensional stability, and less water absorption. Static bending resistance and internal bond resistance also increased significantly. This demonstrated the potential of achieving compatible characteristics for civil construction and furniture production through the inclusion of waste material. The impact of this research is obtained from the utilization of an important agro-industrial residue in the manufacture of permanent composites.

Floating aquatic macrophytes for the treatment of aquaculture effluents.

Aquaculture is an activity with economic and social importance since it generates food, employment, and income. However, like other human activities, it negatively impacts the environment, in this respect mainly due to the production of effluents rich in sedimentable solids, organic matter, phosphorus, and nitrogen. These last two are responsible for the eutrophication of water courses, causing changes in the aquatic biota. Hence, there is a need to adopt strategies to improve the efficiency of wastewater reuse. In this sense, the objective of this work was to evaluate the efficiency of using the floating aquatic macrophytes Eichhornia crassipes, Pistia stratiotes, and Salvinia molesta for the treatment of aquaculture effluents. The experiment was conducted in a completely randomized design, with seven treatments and three repetitions; the treatments were the following: T1, without plant, treated only with sedimentation; T2, Eichhornia crassipes; T3, Pistia stratiotes; T4, Salvinia molesta; T5, Eichhornia crassipes and Pistia stratiotes; T6, Eichhornia crassipes and Salvinia molesta; and T7, Pistia stratiotes and Salvinia molesta. The treatments were evaluated for a period of 168 h: the first collection of effluent allowed analysis of the raw effluent; the second occurred 24 h after the first collection and the others, on alternate days with 72, 120, and 168 h, totaling five collections in each experimental unit. The effluent used came from breeding tanks of Nile Tilapia (Oreochromis niloticus). The quality of the effluent was evaluated by the rate of removal of nutrients N-total, N-nitrite, N-nitrate, N-ammoniacal and Ptotal, temperature, pH, turbidity, dissolved oxygen, electrical conductivity, total alkalinity, BDO, and CDO. After the effluent was treated, the values of the parameters were compared with the maximum admissible values (MAVs), as specified by Brazil's National Environmental Council (CONAMA) in Resolutions 430/2011 and 357/2005. With the use of floating aquatic macrophytes, the concentrations of all evaluated limnology parameters improved significantly. There was also an improvement in the physical aspect of the effluent (transparency and turbidity). Thus, it can be concluded that the use of the macrophytes Eichhornia crassipes, Pistia stratiotes, and Salvinia molesta is effective in the treatment of effluents from fish farming.

Physical-mechanical properties of wood panel composites produced with Qualea sp. sawdust and recycled polypropylene.

Adhesive-free wood-plastic composite panels made with lignocellulosic wastes, and recycled plastics can be a sustainable option for generating useful "green" products. The present work assessed the physical-mechanical properties of adhesive-free panels produced with Qualea sp. sawdust and recycled polypropylene (PP). Discarded PP packaging was used. The packages were washed and ground with a laboratory knife mill until particle size of 10 to 14 mesh. Qualea sp. sawdust was sieved to select particle size of 14 to 30 mesh. Four experimental treatments were assessed by varying the percentages of PP and sawdust, as follows, 60 and 40%, 70 and 30%, 80 and 20%, and 90 and 10%, in an entirely randomized design with 3 panels per treatment, totaling 12 panels. The mats were hot-pressed at 180 °C during 20 min, the first 10 min under pressure of 1.0 MPa and the remaining 10 min at 42 MPa. Physical-mechanical properties of the panels were obtained as follows: density, moisture content, water absorption, thickness swelling, moduli of elasticity and rupture, and Rockwell hardness. In general, an increase of the percentage of PP provided higher dimensional stability to the panels, but there was no significant influence on mechanical strength.