This study investigated the long-term effects of mesophilic (MAD) and thermophilic (TAD) anaerobic digestion on the fate and evolution of antimicrobial resistance genes (ARGs) and mobile genetic elements (MGEs) in cattle manures. One mesophilic (35 °C) and one thermophilic (55 °C) anaerobic digester were set up and operated for over 400 days. The ARG and MGE profiles of their digestates at different time points were determined and analyzed using metagenomics and bioinformatic tools. A total of 100 different ARGs and 246 MGE-related genes were detected in the fresh manures used as the digesters feed. The results indicated that MAD and TAD lowered the levels of ARGs in fresh cattle manure by 53% and 59%, respectively, and MGEs by 65% and 73%, respectively. However, no statistically significant difference was found between MAD and TAD. The analysis of the co-occurrence of ARGs, MGEs, and microbial groups suggested facultative anaerobic species belonging to the Bacillota and Actinomycetota phyla as the primary potential host of these antimicrobial resistance elements. Overall, the results indicated that digested cattle manure (whether under mesophilic or thermophilic conditions) would pose a much lower risk of dissemination of antimicrobial resistance than untreated manures. Moreover, the results also suggested that reducing facultative anaerobic species could reduce levels of antimicrobial resistance. The study provides valuable insights that could help in the development of strategies to reduce the dissemination of antibiotic resistance due to manure treatment and disposal.

Arachidonic acid (ARA) is an omega-6 fatty acid that is important for improving infant memory and eyesight and used to supplement infant formula. Microorganisms that accumulate large amounts of ARA, such as Mortierella alpina, are an attractive source of ARA as they are an alternative to meat-related sources. However, microbial production of ARA from such fungal strains has not been extensively studied. In this work, fermentation strategies were developed at flask-level on a Mortierella strain to optimize its productivity of ARA-containing oils for potential commercial production. In addition, a microbial evolution strategy involving UV mutagenesis coupled with high-throughput screening methods was used to improve the wild type fungal strain and select the most beneficial phenotypes. Plackett-Burman screening, response surface methodology and mixture-design were used to determine the optimal media composition for fermentation experiments. Ultimately, the improvements resulted in a two-fold increase in biomass, ARA content and a five-fold increase in final ARA yield.

Hemp is an environmentally and economically friendly crop, being an attractive option for producers who primarily harvest its seeds and fiber. However, the leaves and crushed buds, by-products of this practice, contain cannabidiol (CBD) and other nutritious compounds having the potential for use in pharmaceuticals or as a source of nutrition. This study aims to provide guidelines for developing post-harvest processes of hemp by-products, in order to add value to agricultural waste and promote sustainable agriculture. The results illustrated that the hemp plant by-products mixture containing about 70% leaves and buds had an average moisture content of 59% (w.b). For safe storage and preparation for extraction, these components were dried by using various drying methods, including oven, microwave-infrared, and microwave-vacuum. Out of all the studied thin layer models, the Page model was the most appropriate model to describe the drying of the hemp plant by-products. The most abundant cannabidiol component hemp plant used in this study was CBDA, with an average of 11.55 mg/g, showing its potential to be used in pharmaceutical applications. Furthermore, our results demonstrated that using the microwave for drying hemp plants is a promising method to enhance CBD and THC contents through the decarboxylation of their acidic forms. Hemp plants' by-products were also a rich source of protein and dietary fiber with an average amount of 20 and 36%, respectively, suggesting its application for feeding purposes.