Maciel, A. | bioRxiv Science

bioRxiv2025

Metaproteomics revealing cyanide bioremediators in effluents from artisanal cassava processing in the Brazilian Amazon

Cassava is widely used and processed for food in several countries. During artisanal processing for flour production, liquid waste containing cyanide may be disposed of inappropriately, contaminating soils, rivers and streams. Various microorganisms must proliferate and carry out fermentation from this waste. The study was carried out on a family farm in the municipality of Braganca, in the state of Para, Brazil. Samples were selected from the effluents generated in four stages (fermentation tank, post-fermentation washing water tank, washing/pressing water tank (manipueira) and effluent lagoon). The aim of this study is therefore to track down microorganisms and their enzymes, through metaproteomics, at all stages of cassava processing up to the elimination of wastewater discharges, using the metaproteomics technique in order to track down potential cyanide bioremediators adapted to local environmental conditions. The samples were extracted using the Phenol-SDS protocol, washed, digested and submitted to a high-resolution mass spectrometer coupled to liquid chromatography and subsequently analyzed using sensitive software. Microorganisms with potential cyanide bioremediation potential were identified (Bacillus subitilis, Pseudomonas putida and Levilactobacillus brevis), as well as nitrogen fixers involved in bioremediation. The identified peptides analyzed showed proteins involved in: DNA repair; glycosylation; phosphorylation; CAZY proteins, among others. These findings provide a foundation for clean biotechnological applications aimed at treating cyanide-contaminated effluents in artisanal cassava processing in the Amazonian territory. ImportanceThis study is important due to the future perspectives for bioremediating cyanide, identifying active enzymes and metabolic pathways, discovering and optimizing consortia of native key microorganisms, monitoring treatment efficiency in real time, having sustainable environmental and human health alternatives, valuing traditional knowledge and regional development in the Amazonian context. Key PointsProspecting for bioremediators generated from cassava effluents; Metaproteomics clarified the microbial dynamics present in cassava effluents; Metaproteomics identifying active enzymes and metabolic functions in biotechnology.

genomics↗

bioRxiv2019

What if I had a third arm? An EEG study of a supernumerary BCI system

Motor imagery Brain-Computer Interface (MI-BCI) enables bodyless communication by means of the imagination of body movements. Since its apparition, MI-BCI has been widely used in applications such as guiding a robotic prosthesis, or the navigation in games and virtual reality (VR) environments. Although psychological experiments, such as the Rubber Hand Illusion - RHI, suggest the human ability for creating body transfer illusions, MI-BCI only uses the imagination of real body parts as neurofeedback training and control commands. The present work studies and explores the inclusion of an imaginary third arm as a part of the control commands for MI-BCI systems. It also compares the effectiveness of using the conventional arrows and fixation cross as training step (Graz condition) against realistic human hands performing the corresponding tasks from a first-person perspective (Hands condition); both conditions wearing a VR headset. Ten healthy subjects participated in a two-session EEG experiment involving open-close hand tasks, including a third arm that comes out from the chest. The EEG analysis shows a strong power decrease in the sensory-motor areas for the third arm task in both training conditions. Such activity is significantly stronger for Hands than Graz condition, suggesting that the realistic scenario can reduce the abstractness of the third arm and improve the generation of motor imagery signals. The cognitive load is also assessed both by NASA-TLX and Task Load index.

neuroscience↗