Phosphate solubilization by Antarctic yeasts isolated from lichens.

Antarctica has a great diversity of microorganisms with biotechnological potential but is not very well Known about yeasts with phosphate solubilization activity. Thus, the aim of this study was to evaluate the ability of yeasts from Antarctica lichens to solubilize phosphate in vitro. In the screening, 147 yeasts were tested and 43 (29%) showed P solubilization in solid NBRIP medium at 15.0 °C, with a higher prevalence of positive genera Vishniacozyma, followed by Cystobasidium. Most of the positive yeasts were isolated from Usnea auratiacoatra, followed by Polycauliona regalis and Lecania brialmontii. Two strains with better activity after screening were selected for the solubilization in the liquid medium, Vishniacozyma victoriae 2.L15 and A.L6 (unidentified). Vishniacozyma victoriae 2.L15 exhibiting activities at 25.0 °C (29.91 mg/L of phosphate and pH 6.85) and at 30.0 °C (619.04 mg/L of phosphate and pH 3.73) and A.L6 strain at 25.0 °C (25.05 mg/L of phosphate and pH 6.69) and at 30.0 °C (31.25 mg/L of phosphate and pH 6.47). Of eight organic acids tested by HPLC, tartaric and acetic acids were detected during phosphate solubilization, with greater release in the period of 144 (2.13 mg/L) and 72 (13.72 mg/L) hours, respectively. Future studies to elucidate the presence of functional genes for P metabolism in lichens, as well as studies in the field of proteomics for the discovery of yeast proteins related to P solubilization are needed. Thus, the high prevalence of lichen-associated yeast communities probably contributed to the high frequency of phosphate-solubilizing isolates in this study.

Cultured and uncultured microbial community associated with biogas production in anaerobic digestion processes.

The search for sustainable development has increased interest in the improvement of technologies that use renewable energy sources. One of the alternatives in the production of renewable energy comes from the use of waste including urban solids, animal excrement from livestock, and biomass residues from agro-industrial plants. These materials may be used in the production of biogas, making its production highly sustainable and environmentally friendly. The present study aimed to evaluate the cultivated and uncultivated microbial community from a substrate (starter) used as an adapter for biogas production in anaerobic digestion processes. 16S rDNA metabarcoding revealed the domain of bacteria belonging to the phyla Firmicutes, Bacteroidota, Chloroflexi and Synergistota. The methanogenic group was represented by the phyla Halobacterota and Euryarchaeota. Through 16S rRNA sequencing of isolates recovered from the starter culture, the genera Rhodococcus (Actinobacteria phylum), Vagococcus, Lysinibacillus, Niallia, Priestia, Robertmurraya, Proteiniclasticum (Firmicutes phylum), and Luteimonas (Proteobacteria phylum) were identified, genera that were not observed in the metabarcoding data. The volatile solids, volatile organic acids, and total inorganic carbon reached 659.10 g kg-1, 717.70 g kg-1, 70,005.0 g kg-1, respectively. The cultured groups are involved in the metabolism of sugars and other compounds derived from lignocellulosic material, as well as in anaerobic methane production processes. The results demonstrate that culture-dependent approaches, such as isolation and sequencing, and culture-independent studies, such as the Metabarcoding approach, are complementary methodologies that, when integrated provide robust and comprehensive information about the microbial communities involved in processes of the production of biogas in anaerobic digestion processes.

Pharmaceutical biotechnological potential of filamentous fungi isolated from textile industry.

The need for more effective drugs for the treatment of infectious diseases as well as for general applications including wound healing and burn surgery, has guided efforts for the discovery of new compounds of medical interest. Microorganisms found in textile industrial waste have the ability to produce a variety of enzymes and/or secondary metabolites including molecules of pharmaceutical interest. The present work investigated the biotechnological potential of filamentous fungi isolated from textile industry wastewater for the production of collagenase and antimicrobial metabolites. From 28 isolates assayed, Sarocladium sp. ITF33 showed specific collagenolytic activity with values of 7.62 and 9.04 U mg-1 for the intracellular and extracellular fractions, respectively. The isolate Penicillium sp. ITF28 showed the best antimicrobial activity, reaching MIC ranging from 1.0 to 0.0625 mg mL-1 against five pathogenic bacteria. Molecular analyzes suggest that the isolate Sarocladium sp. ITF 33 can be considered a species not yet described. The results of the present work encourage studies of characterization and purification of the enzymes and secondary metabolites produced by the isolates found aiming future applications in the medical and pharmaceutical fields.

Environmental change and predator diversity drive alpha and beta diversity in freshwater macro and microorganisms.

Global biodiversity is eroding due to anthropogenic causes, such as climate change, habitat loss, and trophic simplification of biological communities. Most studies address only isolated causes within a single group of organisms; however, biological groups of different trophic levels may respond in particular ways to different environmental impacts. Our study used natural microcosms to investigate the predicted individual and interactive effects of warming, changes in top predator diversity, and habitat size on the alpha and beta diversity of macrofauna, microfauna, and bacteria. Alpha diversity (i.e., richness within each bromeliad) generally explained a larger proportion of the gamma diversity (partitioned in alpha and beta diversity). Overall, dissimilarity between communities occurred due to species turnover and not species loss (nestedness). Nevertheless, the three biological groups responded differently to each environmental stressor. Microfauna were the most sensitive group, with alpha and beta diversity being affected by environmental changes (warming and habitat size) and trophic structure (diversity of top predators). Macrofauna alpha and beta diversity was sensitive to changes in predator diversity and habitat size, but not warming. In contrast, the bacterial community was not influenced by the treatments. The community of each biological group was not mutually concordant with the environmental and trophic changes. Our results demonstrate that distinct anthropogenic impacts differentially affect the components of macro and microorganism diversity through direct and indirect effects (i.e., bottom-up and top-down effects). Therefore, a multitrophic and multispecies approach is necessary to assess the effects of different anthropogenic impacts on biodiversity.