Thermodynamics, Kinetics, and Adsorption Properties of Biomolecules onto Carbon-Based Materials Obtained from Food Wastes

The second life for unused COVID-19 vaccines: Towards biosensing application

Many vaccines have been produced during the COVID-19 pandemic. Currently, an increasing number of vaccines have reached an expiration date without being used. Therefore, expired vaccines (EXVAX) based on virus-like particles (VLP) recombinant SARS-CoV2-S protein can be repurposed for biosensing application and provide a use, even though they are past their expiration date for vaccination. In the current study, we applied EXVAX based on VLP for gold sensor chip modification to use such surface for specific antibody detection from diluted human serum. For this purpose, we used total internal reflection ellipsometry for real-time kinetics measurement and mathematical modelling for the calculation of affinity constants. Moreover, we cross-validated the results obtained with a widely applied ELISA method. EXVAX was tested and compared with commercially available recombinant S proteins analogues that are commonly used for immunosensing. The results suggest that the EXVAX functionalisation is thermodynamically favoured. The interaction analysis of polyclonal antibodies from human serums shows that the EXVAX SARS-CoV2-S proteins retain their biological activity more than one year after the expiration date as the calculated values of the affinity constant fall in a nM range of (10-11 > KD > 10-9), suggesting a high affinity interaction and thus could be used for biosensing and meet sustainable development goal.

Renewable, sustainable, and natural lignocellulosic carriers for lipase immobilization: A review

It is well-known that enzymes are molecules particularly susceptible to pH and temperature variations. Immobilization techniques may overcome this weakness besides improving the reusability of the biocatalysts. Given the strong push toward a circular economy, the use of natural lignocellulosic wastes as supports for enzyme immobilization has been increasingly attractive in recent years. This fact is mainly due to their high availability, low costs, and the possibility of reducing the environmental impact that can occur when they are improperly stored. In addition, they have physical and chemical characteristics suitable for enzyme immobilization (large surface area, high rigidity, porosity, reactive functional groups, etc.). This review aims to guide readers and provide them with the tools necessary to select the most suitable methodology for lipase immobilization on lignocellulosic wastes. The importance and the characteristics of an increasingly interesting enzyme, such as lipase, and the advantages and disadvantages of the different immobilization methods will be discussed. The various kinds of lignocellulosic wastes and the processing required to make them suitable as carriers will be also reported.

Synthesis and application of AuNi@AC nano adsorbents for the removal of Maxilon Blue 5G azo dye from aquatic mediums

In this research, gold-nicel supported on activated carbon (AC) nanoadsorbent (AuNi@AC) synthesized by following a series of physicochemical procedures was prepared for the removal of Maxilon Blue 5G (MB) which is a cationic textile dye. Experimental studies based on parameters specifically pH, contact time, nano catalytic adsorbent particle, initial MB dye concentration and temperature effect were conducted in aqueous solutions in a batch system. AuNi@AC nanoadsorbents (NAs) reached the equilibrium in 30 min under optimum conditions in adsorption of the dye. The pseudo-first, second-order, and intra-particle diffusion models were tested to evaluate a the experimental results. Adsorption kinetics were found to be represented by the pseudo-second-order model, and the maximum adsorption capacity (q_max.) was calculated to be 542.90 mg/g (or 2.041 mmol/g). The synthesized magnetic AuNi@AC nanoadsorbent showed a high-efficiency reusability effect of about 64% after five reuse runs. Also, thermodynamic function parameters such as activation energy (Ea), Gibbs free energy (ΔG *), and entropy (ΔS *) were investigated in the sorption study. After all evaluation of data, it was concluded that the novel AuNi@AC nanoadsorbent could be considered as an effective support material for the removal of various organic pollutants in aquation solution especially for the removal of MB.