Ruminant-Waste Protein Hydrolysates and Their Derivatives as a Bio-Flocculant for Oil Sands Tailing Management.

Reclamation of tailings ponds is a critical issue for the oil industry. After years of consolidation, the slurry in tailings ponds, also known as fluid fine tailings, is mainly comprised of residual bitumen, water, and fine clay particles. To reclaim the lands that these ponds occupy, separation of the solid particles from the liquid phase is necessary to facilitate water removal and recycling. Traditionally, synthetic polymers have been used as flocculants to facilitate this process, but they can have negative environmental consequences. The use of biological polymers may provide a more environmentally friendly approach to flocculation, and eventual soil remediation, due to their natural biodegradability. Peptides derived from specified risk materials (SRM), a proteinaceous waste stream derived from the rendering industry, were investigated to assess their viability for this application. While these peptides could achieve >50% settling within 3 h in bench-scale settling tests using kaolinite tailings, crosslinking peptides with glutaraldehyde greatly improved their flocculation performance, leading to a >50% settling in only 10 min. Settling experiments using materials obtained through different reactant ratios during crosslinking identified a local optimum molar reactant ratio of 1:32 (peptide amino groups to glutaraldehyde aldehyde groups), resulting in 81.6% settling after 48 h. Taken together, these data highlight the novelty of crosslinking waste-derived peptides with glutaraldehyde to generate a value-added bioflocculant with potential for tailings ponds consolidation.

Reverse transcription lesion-induced DNA amplification: An instrument-free isothermal method to detect RNA.

One challenge in point-of-care (POC) diagnostics is the lack of room-temperature methods for RNA detection based on enzymatic amplification and visualization steps. Here we perform reverse transcription lesion-induced DNA amplification (RT-LIDA), an isothermal amplification method that only requires T4 DNA ligase. RT-LIDA involves the RNA-templated ligation of DNA primers to form complementary DNA (cDNA) followed by toehold-mediated strand displacement of the cDNA and its exponential amplification via our isothermal ligase chain reaction LIDA. Each step is tuned to proceed at 28 °C, which falls within the range of global room temperatures. Using RT-LIDA, we can detect as little as ∼100 amol target RNA and can distinguish RNA target from total cellular RNA. Finally, we demonstrate that the resulting DNA amplicons can be detected colorimetrically, also at room temperature, by rapid, target-triggered disassembly of DNA-modified gold nanoparticles. This integrated amplification/detection platform requires no heating or visualization instrumentation, which is an important step towards realizing instrument-free POC testing.