New directions for agricultural wastes valorization as hydrogel biocomposite fertilizers.

The tremendous amount of waste is an environmental and social problem worldwide. The agri-food sector is the largest producer of waste and requires the extensive use of fertilizers, which entails the need to look for innovative solutions in waste management. Properly recycled bio-waste can be reused as fertilizer. Polymer capsules with immobilized waste biomass can be applied as carriers for fertilizer nutrients. The amount of components exerts a certain influence on the effectiveness of copper ions binding. The most important physicochemical properties of biocomposites, such as swelling, SEM (Scanning Electron Microscopy) and FTIR (Fourier Transform Infrared Spectroscopy) were investigated. FTIR analyzes revealed that carboxyl and hydroxyl groups play a key role in Cu2+ ion binding. Morphology analysis showed that ion binding leads to homogenization of the composite surface, while coating the structure makes it more regular and cohesive. The sorption kinetics and the determination of the process's equilibrium parameters (Qmax = 29.4 ± 0.493 mg g-1) play an important role. The study of Cu2+ ion release in different media showed that the chitosan layer slowed down the diffusion of cations by about 50% in NaNO3 (1% m/m) solution. Preliminary studies of the applicability of the capsules in germination tests demonstrate that the biocomposites have no phytotoxic effects on the test plant. The chitosan coating slows the release of Cu2+ ions by about 20% compared to uncoated capsules. New fertilizer formulations containing chitosan-encapsulated hydrogel with biomass-immobilized micronutrients can be applied for precision agriculture to minimize the loss of fertilizer nutrients to the environment. These fertilizers could be used to cultivate houseplants and greenhouse crops.

New trends in biotechnological applications of photosynthetic microorganisms.

As a source of several valuable products, photosynthetic microorganisms (microalgae and cyanobacteria) have many applications in biomedical, electrochemical, and urban-space fields. Microalgal and cyanobacterial (photoautotrophs) implementations have been the subject matter of several reviews, which mainly focused on exploring effective methods of their harvesting, optimal cultivation conditions, energy conversion efficiency, and new strategies for microalgal health-promoting compound recovery. This review highlights recent investigations into biomedical, urban, environmental, and electrical engineering microalgae and cyanobacteria applications over the last seven years. A brief historical outline of advances in photoautotroph-based technologies is presented prior to an exploration of the important role of these microorganisms in combating global warming and food and energy insecurity. Special attention is given to the photosynthetic oxygen production of algae and the possibility of treating hypoxia-associated diseases such as cancer or tissue injuries. Photoautotroph applications in microrobotics, drug delivery and wound healing systems, biosensors, and bioelectronics are also introduced and discussed. Finally, we present emerging fabrication techniques, such as additive manufacturing, that unleash the full potential of autotrophic, self-sufficient microorganisms at both the micro- and macroscales. This review constitutes an original contribution to photoautotroph biotechnology and is thought to be impactful in determining the future roles of microalgae and cyanobacteria in medical, electrical, or urban space applications.

3D Printing of Thermoresponsive Hydrogel Laden with an Antimicrobial Agent towards Wound Healing Applications.

Thermoresponsive hydrogel-based wound dressings with an incorporated antimicrobial agent can be fabricated employing 3D printing technology. A novel printable ink containing poly(N-isopropylacrylamide) (PNIPAAm) precursors, sodium alginate (ALG), methylcellulose (MC) that is laden with a mixture of octenidine dihydrochloride and 2-phenoxyethanol (Octenisept®, OCT) possess accurate printability and shape fidelity. This study also provides the protocol of ink's use for the 3D printing of hydrogel scaffolds. The hydrogel's physicochemical properties and drug release profiles from the hydrogel specimens to the external solution have been determined at two temperatures (20 and 37 °C). The release test showed a sustained OCT delivery into ultrapure water and the PBS solution. The temperature-responsive hydrogel exhibited antimicrobial activity against Staphylococcus aureus, Candida albicans, and Pseudomonas aeruginosa and demonstrated non-cytotoxicity towards fibroblasts. The thermoresponsive behavior along with biocompatibility, antimicrobial activity, and controlled drug release make this hydrogel a promising class of materials for wound dressing applications.

Concentration of natural aroma compounds from fruit juice hydrolates by pervaporation in laboratory and semi-technical scale. Part 1. Base study.

The first article of a two-article series presents pervaporation (PV) of volatile aroma compounds from fruit juice hydrolates (plum, apple, blackcurrant and cherry). The purpose of this research was to evaluate the effectiveness of fruit juice hydrolates separation on a laboratory scale (inert gas flow pervaporation system) and semi-technical (vacuum pervaporation system) by means of pervaporation. To create precise matrices for hydrolates before and after pervaporation for each of the separated systems, solid phase microextraction (SPME) technique and the gas chromatography-mass spectrometry (GC-MS) was applied. Sensory analysis confirmed improvement of aroma note of concentrated permeates as compared to feed hydrolates solutions. The results indicated that pervaporation may be applied in condensing aromatic water or fruit juice hydrolate, which may significantly enhance product quality and lengthen shelf life.