Differences in fungal communities associated to Festuca paniculata roots in subalpine grasslands

International audienceMycorrhizal fungi or endphytes colonize plant roots and their occurrence and composition depend on biotic and abiotic characteristics of the ecosystem. We investigated the composition of these microbial communities associated with Festuca paniculata, a slow growing species, which dramatically impacts functional plant diversity and the recycling of organic matter in subalpine grasslands. F. paniculata individuals from both mown and unmown grasslands were randomly collected and the microscopic observation of the plant roots revealed a difference in fungal colonization according to management. The ITS regions of root-associated fungi were amplified, cloned and sequenced. Bioinformatic analysis revealed a total of 43 and 35 phylotypes in mown and unmown grasslands respectively, highlighting a remarkable difference in the composition between both fungal communities. The phylotypes were assigned to 9 classes in which two classes Eurotiomycetes and Lecanoromycetes were specific to mown grasslands, while Tremellomycetes were specific to unmown grasslands and only five phylotypes were common to both locations. The comparative analysis of fungal lifestyles indicated the dominance of saprobes and a large proportion of endophytes compared to the mycorrhizal fungi (7/1 and 11/2 phylotypes in mown and unmown grasslands, respectively). Endophyte richness was greater in the unmown gassland than in the mown grassland and their relative proportion was twice higher. Our results suggest that endophytes may offer potential resources to F. paniculata and play an important role in the regulation of plant diversity

Rheological, Textural, Physicochemical and Sensory Profiling of a Novel Functional Ice Cream Enriched with Muscat de Hamburg (Vitis vinifera L.) Grape Pulp and Skins

International audienceThe scope of the present work was the development of an ice cream containing substantial amount of phenolic compounds by substituting sucrose by a Muscat de Hamburg grape pulp and skin matter (GPSM)-enriched bulking agent at the level of 25 to 100% w/w. Sucrose replacement by GPSM reinforced the pseudoplastic and thixotropic character of the ice cream mixes imparting weak gel-like properties (G>G). Oscillatory thermo-mechanical analysis revealed the occurrence of a -relaxation peak at -17 to -12.8 degrees C, whilst a slight depression of the freezing point was observed. The increase in GPSM solids resulted in a significant increase in the instrumental hardness and overrun of ice cream samples, whilst it enhanced their meltdown resistance. Although GPSM boosted the nutritional value and flavour profile of the ice cream, when sucrose substitution exceeded 50%, undesirable sensory characteristics, such as coarse/grainy texture, bitterness and astringency, were detected

Biodegradation of poly(ester‐urethane) coatings by Halopseudomonas formosensis

Abstract Impranil® DLN‐SD is a poly(ester‐urethane) (PEU) that is widely used as coating material for textiles to fine‐tune and improve their properties. Since coatings increase the complexity of such plastic materials, they can pose a hindrance for sustainable end‐of‐life solutions of plastics using enzymes or microorganisms. In this study, we isolated Halopseudomonas formosensis FZJ due to its ability to grow on Impranil DLN‐SD and other PEUs as sole carbon sources. The isolated strain was exceptionally thermotolerant as it could degrade Impranil DLN‐SD at up to 50°C. We identified several putative extracellular hydrolases of which the polyester hydrolase Hfor_PE‐H showed substrate degradation of Impranil DLN‐SD and thus was purified and characterized in detail. Hfor_PE‐H showed moderate temperature stability (Tm = 53.9°C) and exhibited activity towards Impranil DLN‐SD as well as polyethylene terephthalate. Moreover, we revealed the enzymatic release of monomers from Impranil DLN‐SD by Hfor_PE‐H using GC‐ToF‐MS and could decipher the associated metabolic pathways in H. formosensis FZJ. Overall, this study provides detailed insights into the microbial and enzymatic degradation of PEU coatings, thereby deepening our understanding of microbial coating degradation in both contained and natural environments. Moreover, the study highlights the relevance of the genus Halopseudomonas and especially the novel isolate and its enzymes for future bio‐upcycling processes of coated plastic materials