Polysaccharide hydrogels have been increasingly utilized in various fields. In this review, we focus on polysaccharide-based hydrogels used as probiotic delivery systems. Probiotics are microorganisms with a positive influence on our health that live in the intestines. Unfortunately, probiotic bacteria are sensitive to certain conditions, such as the acidity of the gastric juice. Polysaccharide hydrogels can provide a physical barrier between encapsulated probiotic cells and the harmful environment enhancing the cells survival rate. Additionally, hydrogels improve survivability of probiotic bacteria not only under gastrointestinal track conditions but also during storage at various temperatures or heat treatment. The hydrogels described in this review are based on selected polysaccharides: alginate, κ-carrageenan, xanthan, pectin and chitosan. Some hydrogels are obtained from the mixture of two polysaccharides or polysaccharide and non-polysaccharide compounds. The article discusses the efficiency of probiotic delivery systems made of single polysaccharide, as well as of systems comprising more than one component.

There is an increasing demand for bio-based polymers that are developed from recycled materials. The production of biodegradable polymers can include bio-technological (utilizing microorganisms or enzymes) or chemical synthesis procedures. This report demonstrates the corroboration of the molecular structure of polyhydroxyalkanoates (PHAs) obtained by the conversion of waste polyethylene (PE) via non-oxygenated PE wax (N-PEW) as an additional carbon source for a bacterial species. The N-PEW, obtained from a PE pyrolysis reaction, has been found to be a beneficial carbon source for PHA production with Cupriavidus necator H16. The production of the N-PEW is an alternative to oxidized polyethylene wax (O-PEW) (that has been used as a carbon source previously) as it is less time consuming to manufacture and offers fewer industrial applications. A range of molecular structural analytical techniques were performed on the PHAs obtained; which included nuclear magnetic resonance (NMR) and electrospray ionisation tandem mass spectrometry (ESI-MS/MS). Our study showed that the PHA formed from N-PEW contained 3-hydroxybutyrate (HB) with 11 mol% of 3-hydroxyvalerate (HV) units.

The herbicide 2-methyl-4-chlorophenoxyacetic acid (MCPA) conjugated with poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) was prepared via a melt transesterification route. The resultant bioactive oligomer was then mixed with a blend of polylactide (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) with different loadings to manufacture films to be used as a bioactive, biodegradable mulch to deliver the herbicide to target broadleaf weed species. The biological targeting of the MCPA-PHBV conjugate in the mulch film was investigated under glasshouse conditions using faba bean (Vicia faba) as a selective (nontarget) model crop species having broadleaf morphology. The presence of the MCPA-PHBV conjugate in the biodegradable PBTA/PLA blend was shown to completely suppress the growth of broadleaf weed species while displaying only a mild effect on the growth of the model crop. The degradation of the mulch film under glasshouse conditions was quite slow. The release of the MCPA-PHBV during this process was detected using NMR, GPC, EDS, and DSC analyses, indicating that the majority of the MCPA diffused out after MCPA-PHBV conjugate bond scission. These data provide a strong “proof of concept” and show that this biodegradable, bioactive film is a good candidate for future field applications and may be of wide agricultural applicability.

The main aim of the present study was to determine the behavior of the specimens from Ecovio, in the form of dumbbell-shaped samples and films, during degradation in selected cosmetic ingredients such as water and paraffin. The (bio)degradation test of the prototype cosmetic package (sachet) made from a PBAT (poly[(1,4-butylene adipate)-co-(1,4-butylene terephthalate)]) and PLA (polylactide) blend was investigated under industrial composting conditions, and compared with the sample behavior during incubation in cosmetic media at 70 °C. During the degradation tests, the changes of the samples were evaluated using optical microscopy, ¹H NMR (proton nuclear magnetic resonance) and GPC (gel permeation chromatography) techniques. The structures of the degradation products were investigated using ESI-MSⁿ (mass spectrometry with electrospray ionization on positive and negative ions) analysis. The thermal properties of selected materials were determined by DSC (differential scanning calorimetry) and TGA (thermogravimetric analysis) analysis. It was concluded that the PBAT and PLA blend studied had a good stability during aging in cosmetic media, and could be recommended for long-shelf-life compostable packaging of cosmetics, especially with oily ingredients.