Antarctic marine sediment as a source of filamentous fungi-derived antimicrobial and antitumor compounds of pharmaceutical interest.

Antarctica harbors a microbial diversity still poorly explored and of inestimable biotechnological value. Cold-adapted microorganisms can produce a diverse range of metabolites stable at low temperatures, making these compounds industrially interesting for biotechnological use. The present work investigated the biotechnological potential for antimicrobial and antitumor activity of filamentous fungi and bacteria isolated from marine sediment samples collected at Deception Island, Antarctica. A total of 89 microbial isolates were recovered from marine sediments and submitted to an initial screening for L-glutaminase with antitumoral activity and for antimicrobial metabolites. The isolates Pseudogymnoascus sp. FDG01, Pseudogymnoascus sp. FDG02, and Penicillium sp. FAD33 showed potential antiproliferative action against human pancreatic carcinoma cells while showing no toxic effect on non-tumor cells. The microbial extracts from unidentified three bacteria and four filamentous fungi showed antibacterial activity against at least one tested pathogenic bacterial strain. The isolate FDG01 inhibited four bacterial species, while the isolate FDG01 was active against Micrococcus luteus in the minimal inhibitory concentration of 0.015625 µg mL -1. The results pave the way for further optimization of enzyme production and characterization of enzymes and metabolites found and reaffirm Antarctic marine environments as a wealthy source of compounds potentially applicable in the healthcare and pharmaceutical industry.

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.

DNA Metabarcoding from Microbial Communities Recovered from Stream and Its Potential for Bioremediation Processes.

Urban waste (UW) has caused a series of problems regarding its management. UW comprises domestic, hospital and industrial residues, which makes the destination of this waste a matter of concern, as it may contain a variety of highly toxic environmental polluters. Deactivated dumps can represent sources of contamination of the environment that surround these deposits, harming rivers and inhabiting organisms. Knowledge of the microbial profile of water bodies that can be affected by these toxic residues is essential for the development of alternatives and improvements in treatments applied in rivers and streams. In this sense, this work aimed to analyze the microbial community present in sediments of the Arroio Dourado stream in the municipality of Foz do Iguaçu, a stream located near a deactivated open-air dump. 16S rDNA metabarcoding suggested the dominance of acidogenic bacteria belonging to Acidobacteriota phylum, followed by less abundant phyla Actinobacteriota, Myxococcota, Chloroflexi and a small community of sulfate reducers (Desulfobacteriota). However, more than 50% of amplicon sequence variants (ASVs) were not taxonomically classified. In addition, an expressive abundance was attributed to the genus Anaeromyxobacter, a metabolically versatile group, which can thrive in the presence of polluting compounds present in the deactivated landfill. Thus, a possible stream treatment process can be developed. In addition, culture media can be developed for the recovery of taxonomic groups identified involved in the biodegradation of organic compounds. The results presented expand the knowledge of bacterial diversity in sediment samples recovered from the Arroio Dourado stream.

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.

Undecane production by cold-adapted bacteria from Antarctica.

In the last decades, efforts to reduce the use of fossil fuels have increased the search for alternative sustainable sources of renewable energy. In this scenario, hydrocarbons derived from fatty acids are among the compounds that have been drawing attention. The intracellular production of hydrocarbons by bacteria derived from cold environments such as the Antarctic continent is currently poorly investigated, as extremophilic microorganisms provide a great range of metabolic capabilities and may represent a key tool in the production of biofuels. The aim of this study was to explore the ability of bacterial cells derived from extreme environments to produce hydrocarbons with potential for further use as biofuels. Seven bacteria isolated from Antarctic samples were evaluated for hydrocarbon production using GC-MS approaches. Two isolates, identified as Arthrobacter livingstonensis 593 and Pseudoalteromonas arctica 628, were able to produce the hydrocarbon undecane (CH3-(CH2)9-CH3) in concentrations of 1.39 mg L-1 and 1.81 mg L-1, respectively. Results from the present work encourage further research focusing on the optimization of hydrocarbon production by the isolates identified as producers, which may be used in further aircraft biofuel production. This is the first report on the production of the undecane compound by bacteria isolated from waterlogged soil and sponge from Antarctica.

Antimicrobial activity against Microcystis aeruginosa and degradation of microcystin-LR by bacteria isolated from Antarctica.

Cyanobacteria massive proliferations are common in freshwater bodies worldwide, causing adverse effects on aquatic ecosystems and public health. Numerous species develop blooms. Most of them correspond to the toxic microcystin-producing cyanobacterium Microcystis aeruginosa. Microorganisms recovered from Antarctic environment can be considered an unexploited source of antimicrobial compounds. Data about their activity against cyanobacteria are scant or inexistent. This study aimed to evaluate the capacity of Antarctic bacteria to inhibit the proliferation of M. aeruginosa BCPUSP232 and to degrade microcystin-LR (MC-LR). Cell-free extracts of seventy-six bacterial strains were initially tested for antimicrobial activity. Unidentified (UN) strains 62 and ES7 and Psychromonas arctica were able to effectively lyse M. aeruginosa. Eight strains showed MIC ranging from 0.55 to 3.00 mg mL-1, with ES7 showing the best antimicrobial activity. Arthrobacter sp. 443 and UN 383 were the most efficient in degrading MC-LR, with 24.87 and 23.85% degradation, respectively. To our knowledge, this is the first report of antimicrobial and MC-LR degradation activities by Antarctic bacteria, opening up perspectives for their future application as an alternative or supporting approach to help mitigate cyanobacterial blooms.