Rapid and qualitative fluorescence-based method for the assessment of PHA production in marine bacteria during batch culture.

The expansion of polyhydroxyalkanoates (PHAs) into the biodegradable polymers market is mainly prevented by their production process which is still complicated with a low efficiency, resulting in relatively expensive products. In this study, we developed a method that used the lipophilic fluorescent probe Nile Red (1 mg l(-1) solution in DMSO) directly into the culture broth to stain the PHA inclusions inside bacterial cells followed by detection of the emitted fluorescence by both microscopic and spectrometric techniques. Epifluorescence microscopy provides a rapid tool to distinguish producing from non-producing bacterial species and the relative fluorescence intensity (FI) determined at the maximum of emission spectra in the wavelength region of 560-710 nm (λ(ex): 543 nm), allows a fast assessment of the cultural conditions that may enhance PHA production yield. During two-step cultivation in 500-ml flasks with glucose as the sole carbon source, the method aimed to select bacterial strains efficient for PHA synthesis among a marine collection. Subsequently, the NR assay was used to determine the C0/N0 ratio of the producing media that may improve the polymer yield as well as to follow the time course of fermentation. Characterization by GC-MS and DSC confirmed the production of the P(3-HB) homopolymer.

Editorial: biodegradable materials.

This Special Issue "Biodegradable Materials" features research and review papers concerning recent advances on the development, synthesis, testing and characterisation of biomaterials. These biomaterials, derived from natural and renewable sources, offer a potential alternative to existing non-biodegradable materials with application to the food and biomedical industries amongst many others. In this Special Issue, the work is expanded to include the combined use of fillers that can enhance the properties of biomaterials prepared as films. The future application of these biomaterials could have an impact not only at the economic level, but also for the improvement of the environment.

Studies of a furanoside as antimycobacterial agent loaded into a biodegradable PBAT/sodium caseinate support.

An improved synthesis of n-octyl ß-D-galactofuranoside was described using micro-wave activation. The resulting alkyl furanoside showed antibacterial activity against Mycobacterium smegmatis, a non-pathogenic model of Mycobacterium tuberculosis. It was further incorporated into a biodegradable PBAT/sodium caseinate polymer. The resulting biomaterial loaded with 5% of the pharmacophore retained the mycobacteriostatic properties and developed a mycobactericidal activity on contact and at the periphery of the film.