Biol. Life Sci. Forum, 2023, ENVABIO100

Lactic acid is a compound used industrially due to its properties. There are two methods for its production: chemical synthesis and microbial fermentation. In microbial fermentation, food industry waste can be used as a substrate, providing a route towards achieving a circular economy. Thus, this study evaluated different substrates for Lactobacillus plantarum growth, a lactic acid producer, such as molasses, whey, glucose, and saccharose, either alone or supplemented with additional nutrients. Bacterial growth parameters were assessed using OD₆₂₀ measurement. It was shown that whey supplemented with yeast extract supported the best growth, allowing a μ_max = 0.63 h⁻¹. Full article

This work presents a review related to the obtainment of cellulose from different structures in agro-industrial residues, both for application in the food industry and for the reinforcement of other materials. Cellulose nanofibers are produced by the heart of palm (Bactris gasipaes) industry in Brazil and are used as a stabilizer in avocado oil emulsions; conversely, cellulose nanocrystals are produced in waste from the tequila industry (Agave tequilana Weber var. Azul) in Jalisco, Mexico, and are used for reinforcement applications. Full article

Pectin is a polysaccharide that is known for its gelling properties and its applications in the pharmaceutical industry. This can be divided into two structural groups, high methoxyl pectins (HMP) and low methoxyl pectins (LMP). Currently, there is little information on the properties of the orange pectin in which LPM predominates. The aim of this study was therefore to investigate the mechanical properties of gels produced with pectin isolated from orange peels. The results showed similar values to those found in the literature, except for hardness. The gels produced from the pectin could be used in the industry, the formulation varying depending on the application. Full article

Thermoplastic starch films (TPS) are an alternative for single-use plastics in packaging. Evaluating large-scale production alternatives that maintain the properties of these bio-based polymers is a crucial factor in understanding their potential industrial use. This preliminary study focuses on testing whether a mathematical model used to predict the drying conditions of ceramic film via tape casting can be adapted to the production of TPS. It also determines the possible drying tape speeds for this type of polymeric film. Full article

Broccoli is a highly perishable vegetable with unique nutritional characteristics. Modified atmosphere packaging (MAP) has proven to be a successful technology to extend broccoli shelf-life. The main disadvantage of MAP is the extensive use of petrochemical-based films resulting in huge quantities of domestic plastic waste. In this study, suitability of a biodegradable cellulose-based film for broccoli florets packaging was evaluated, as an alternative to polypropylene film. Florets packaged in cellulose-based film showed a high mass loss and extremely low in-package O₂ concentrations, which made this material unsuitable for broccoli packaging application. Improved gas and water vapor barrier properties should be considered for biodegradable packages, in order to make their application for vegetable packaging feasible. Full article

Phenolic compounds from propolis extract (PE) have antioxidant and antimicrobial properties; however, extracts from this raw material are not water soluble. This study aimed to stabilize the phenolic compounds from green propolis extract in cassava and potato starch nanoparticles produced by the anti-solvent precipitation method. The obtained materials displayed a crystalline structure related to starch nanomaterials with a V_6h-type crystalline structure. The starch nanoparticles interacted with the phenolic compounds by means of hydrogen bonds and increased the hydrophobicity in the nanomaterials. The developed starch nanomaterials loaded with the phenolic compounds from PE could be potentially used as a novel ingredient in food packaging. Full article

In the context of the so-called lignocellulose bio-refinery, the coconut shell (S) and pulp (P) of Acrocomia aculeata (Arecaceae) are interesting agro-industrial wastes that can be used as feedstock for the production of high value-added products. The aim of this work was to evaluate these lignocellulosic residues S and P, to obtain the microcrystal (MCC) and microfiber (MFC) of cellulose, and to characterize them to propose possible applications. First, cellulose content in the raw materials was determined, being 39.69% and 45.42% for both (S and P)) respectively, respectively. Then, the purification of residues was carried out via alkaline and bleaching treatments. Next, in order to obtain MCC and MFC from the purified cellulose, a chemical treatment with HCl (for MCC) and a mechanical treatment with a blender (for MFC) were performed. The size and morphology were observed via MEB, and properties were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and differential thermogravimetric analysis (DTG). Full article

A study of materials for wind turbine blades with nanotechnology—from the energy point of view—is an essential topic because resources and fossil fuels are running out. Human beings need to create alternative energies, including wind energy. This research aims to improve the mechanical properties of epoxy resin wind turbine blades by incorporating nanocelluloses obtained from pineapple residues. To determine the quality of the nanobiocomposites, materials with different epoxy resin–nanocellulose ratios were prepared. The mechanical properties of tension, compression, and bending were evaluated, and hardness tests of the material were conducted. The results indicated a general improvement in all the mechanical properties considered over the material without the nanocellulose. Full article

The objective of this work was to formulate PVA films with the addition of modified phenols, chitosan, silver, or copper nanoparticles with fungistatic and bacteriostatic activity. The films were characterized by Fourier transform infrared spectroscopy, thermogravimetry analysis, differential scanning calorimetry, and scanning electron microscopy. The bacteriostatic activity against Salmonella gallinarum and Lactobacillus acidophilus, and the fungistatic activity against Penicillium acidophilus were determined. The results indicated that the addition of phenols enhanced the effect on the stability of the chemical structure of the PVA film. PVA films with modified bioactives and nanoparticles inhibited the colonization of the microorganisms tested, indicating germicidal control. Full article

It is undeniable that suitable packaging will extend the shelf life of the food. The packaging industry has had to renew and innovate in a world where consumers are increasingly environmentally conscious in order to deal with the impact of the production of petroleum-derived plastics and the management of the waste generated by them. In this way, the use of biopolymers has been proposed, mainly those produced from renewable sources and with biodegradability and/or compostability properties. However, these types of materials are more expensive and do not have the same performance as petroleum-derived materials. Besides, the technologies for film preparation are not adapted for these materials. Therefore, new technologies must be studied and implemented to make the packaging industry a sustainable industry. Recently, non-solvent phase inversion (NIPS) and electrospinning techniques, which are widely used for membrane fabrication, have been proposed for the fabrication of films for food packaging applications from biopolymers and green solvents. Full article

Biotechnology is essential for developing profitable and productive techniques to obtain metabolites. Two technologies can be used: solid or liquid fermentation and enzymatic treatments. In this context, the objective of this work was to evaluate the use of rice husk, a lignocellulosic material, to obtain bioactive compounds by lignin oxidative transformation and demethoxylation, respectively, through enzymatic treatments of P. chrysosporium and G. trabeum. In the first step, solid fermentation was used to obtain the enzyme Lig. Peroxidase and methoxyl hydrolase were quantified as 80 UE and 50 UE, respectively. This enzyme concentrate was lyophilized and used to prepare an enzymatic consortium (240 UE LigP and 150 UE metH) applied in the second phase of enzymatic treatment. The overall process involved 20 days in the solid fermentation step and 2 h for the enzymatic treatment. The obtained products were characterized by having veratryl alcohol and veratryl aldehyde at contents of 70.4 ± 0.1 and 23.3 ± 0.3 mg/g, respectively. Moreover, the analyzed products did not show cytotoxicity but revealed antioxidant and bacteriostatic activities. No anti-inflammatory activity was detected. In the context of circular economy, the obtained results pointed out the use of combined solid fermentation and enzymatic treatment as a viable strategy to valorize rice husk. The applications of these bioactive compounds presenting bactericidal and bacteriostatic activity and not showing toxicity are very common in medicine, agriculture, and environmental health, among others, and can be incorporated both in free systems and immobilized in spheres, capsules or biopolymer films, which is an important input for obtaining functionalized materials that are in high demand today. Full article

The increasing global consumption of conventional plastics has led to significant environmental challenges due to their resistance to degradation and dependency on petroleum, a volatile resource. In this context, polylactic acid (PLA) has emerged as a promising biopolymer alternative, offering excellent physical and mechanical properties while being derived from renewable resources. The synthesis of PLA involves the production of lactide, a crucial cyclic monomer. This study focuses on lactide synthesis using zinc oxide (ZnO) nanoparticles as catalysts. The synthesis process consists of three stages: the dehydration of lactic acid, oligomerization to obtain a PLA oligomer, and depolymerization with simultaneous distillation to produce lactide. The ZnO nanoparticle catalyst proved to be highly efficient in regulating the molecular weight of the oligomer during depolymerization, which directly impacts the molecular weight of the PLA. The lactide purification using ethyl acetate resulted in an average purity of 90.0 ± 1.79%, demonstrating the effectiveness of the purification process. The quantification of lactide through high-performance liquid chromatography (HPLC) showed excellent linearities, allowing for the accurate determination of lactide content. The lactide synthesis yielded 77–80%, and the stability of the synthesized lactide was confirmed through a second purity determination after four months, with only a 1.7% loss in lactide content. Overall, this study showcases the feasibility of lactide synthesis using ZnO nanoparticles as catalysts and contributes valuable insights into producing high-quality lactides for PLA manufacturing. Full article