Effects of Electrolytes, Water, and Temperature on Cross-Linking of Glutaraldehyde and Hydrolyzed Specified Risk Material

Valorization strategies for hazardous proteinaceous waste from rendering production - Recent advances in specified risk materials (SRMs) conversion

Strict bans on specific risk materials (SRMs) are in place to prevent the spread of bovine spongiform encephalopathy (BSE). SRMs are characterized as tissues in cattle where misfolded proteins, the potential source of BSE infection, are concentrated. As a result of these bans, SRMs must be strictly isolated and disposed of, resulting in great costs for rendering companies. The increasing yield and the landfill of SRMs also exacerbated the burden on the environment. To cope with the emergence of SRMs, novel disposal methods and feasible value-added conversion routes are needed. The focus of this review is on the valorization progress achieved in the conversion of peptides derived from SRMs via an alternative disposal method, thermal hydrolysis. Promising value-added conversion of SRM-derived peptides into tackifiers, wood adhesives, flocculants, and bioplastics, is introduced. The potential conjugation strategies that can be adapted to SRM-derived peptides for desired properties are also critically reviewed. The purpose of this review is to discover a technical platform through which other hazardous proteinaceous waste, SRMs, can be treated as a high-demand feedstock for the production of renewable materials.

Covalently Immobilized Regenerable Immunoaffinity Layer with Orientation-Controlled Antibodies Based on Z-Domain Autodisplay

A regenerable immunoaffinity layer comprising covalently immobilized orientation-controlled antibodies was developed for use in a surface plasmon resonance (SPR) biosensor. For antibody orientation control, antibody-binding Z-domain-autodisplaying Escherichia coli (E. coli) cells and their outer membrane (OM) were utilized, and a disuccinimidyl crosslinker was employed for covalent antibody binding. To fabricate the regenerable immunoaffinity layer, capture antibodies were bound to autodisplayed Z-domains, and then treated with the crosslinker for chemical fixation to the Z-domains. Various crosslinkers, namely disuccinimidyl glutarate (DSG), disuccinimidyl suberate (DSS) and poly (ethylene glycol)-ylated bis (sulfosuccinimidyl)suberate (BS(PEG)₅), were evaluated, and DSS at a concentration of 500 μM was confirmed to be optimal. The E. coli-cell-based regenerable HRP immunoassay was evaluated employing three sequential HRP treatment and regeneration steps. Then, the Oms of E. coli cells were isolated and layered on a microplate and regenerable OM-based HRP immunoassaying was evaluated. Five HRP immunoassays with four regeneration steps were found to be feasible. This regenerable, covalently immobilized, orientation-controlled OM-based immunoaffinity layer was applied to an SPR biosensor, which was capable of quantifying C-reactive protein (CRP). Five regeneration cycles were repeated using the demonstrated immunoaffinity layer with a signal difference of <10%.

Influence of Glutaraldehyde's Molecular Transformations on Spectroscopic Investigations of Its Conjugation with Amine-Modified Fe3O4 Microparticles in the Reaction Medium

Glutaraldehyde (GA) is a widely used cross-linking agent in biological research due to its superior characteristics, such as high reactivity toward proteins, high stability, and cost-effectiveness. In this regard, analyzing spectral changes initiated by various molecular forms and transformations of GA in a reaction medium and its reaction with surface functional-modified solid spheres is vital for a successful bioconjugation process targeting the biomolecules of interest. In this work, we present Fourier transform-infrared (FT-IR), Raman, and UV-visible spectroscopic analyses of glutaraldehyde-modified Fe₃O₄ microparticles (magnetic beads) to confirm the conjugation between GA and magnetic beads. We also studied the molecular transformations of glutaraldehyde during the reaction with amine-modified magnetic beads via investigating the reaction medium of the glutaraldehyde solution. Our FT-IR and Raman studies confirmed that glutaraldehyde was successfully coupled on the magnetic beads. Furthermore, FT-IR and UV-vis studies on the glutaraldehyde solution revealed the multiple molecular forms of GA in an aqueous medium, and they also confirmed that glutaraldehyde transforms into other molecular forms while the reaction occurs with the magnetic beads.

Ambient alkaline hydrolysis and anaerobic digestion as a mortality management strategy for whole poultry carcasses

Livestock mortality management is a critical factor for ensuring biosecurity, minimizing environmental impact, and maintaining public trust in livestock production agriculture. The number of technologies currently used for livestock mortality management is small, including composting, burial, incineration, landfilling, and rendering. Each technology has advantages and disadvantages which make their suitability situational. In this study, ambient alkaline hydrolysis (AAH) using 2, 4, or 8 M potassium hydroxide at ambient temperature and pressure was explored as a disposal method for whole broiler chicken carcasses. Alkaline hydrolysate (pH > 14) resulting from the process was neutralized by mixing with acidic corn silage, and then utilized as a substrate for anaerobic digestion in bench top continuously stirred tank reactors. All AAH treatments solubilized broiler carcasses within 20 days. Corn silage neutralized 2 M hydrolysate using a 2:1 (w/w) mixing ratio, while 4 M hydrolysate required a 4:1 mixing ratio. Anaerobic digestion of neutralized hydrolysate reduced volatile solids by >96% for all treatments. Highest methane yields were observed from the 2 M hydrolysate (607.2 ± 47.9 g mL^-1 VS), while biogas production from the 8 M hydrolysate was totally inhibited over a total of 42 days. Ambient alkaline hydrolysis followed by silage neutralization and anaerobic digestion provides a feasible, straightforward technology to manage routine and emergency animal mortalities.