Significance of the presence of antibiotics on the microbial consortium in wastewater - The case of nitrofurantoin and furazolidone.

Antibiotics in wastewater leads to migration of pollutants and disrupts natural processes of mineralization of organic matter. In order to understand the mechanism of this, research was undertaken on the influence of nitrofurantoin (NFT) and furazolidone (FZD), on the behaviour of a consortium of microorganisms present in a model wastewater in a bioreactor. Our study confirmed biodegradation of the antibiotics by the microbial consortium, with the degradation efficiency within 10 days of 65% for FZD, but only 20% for NFT. The kinetic study proved that the presence of analysed antibiotics had no adverse effect on the microbes, but the consortium behaviour differ significantly with the NFT reducing the consumption of organic carbon in wastewater and increasing the production of extracellular biopolymeric and volatile organic compounds, and the FZD reducing assimilation of other carbon sources to a less extent, at the expense of cellular focus on biodegradation of this antibiotic

Enzyme immobilization by adsorption : a review

Endowed with unparalleled high catalytic activity and selectivity, enzymes offer enormous potential as catalysts in practical applications. These applications, however, are seriously hampered by enzymes’ low thermal and chemical stabilities. One way to improve these stabilities is the enzyme immobilization. Among various tested methods of this process that make use of different enzyme-carrier interactions, immobilization by adsorption on solid carriers has appeared most common. According to these findings, in this review we present a comparative analysis of the literature reports on the recent trends in the immobilization of the enzymes by adsorption. This thorough study was prepared in order to provide a deeper understanding of the process. Both carriers, carrier modifiers and procedures developed for effective adsorption of the enzymes are discussed. The review may thus be helpful in choosing the right adsorption scheme for a given enzyme to achieve the improvement of its stability and activity for a specific application

The shadow pandemic of single use personal protective equipment plastic waste: A blue print for suppression and eradication

Single use personal protective equipment (PPE) has played a major role in preventing COVID-19 infection. Since the beginning of the COVID-19 pandemic, over 4 million tonnes of polypropylene PPE waste has been disposed into the environment in uncontrolled manner causing significant and long-term ecological damage. This work also highlights several effective measures to alleviate the problem of polypropylene PPE waste. Short-term measures include knowledge sharing to minimise the use of single use PPE and to adapt innovative polypropylene recycling technologies. To prepare for a future pandemic, it is also essential to phase out polypropylene PPE using natural based polymers

The response surface methodology for optimization of tyrosinase immobilization onto electrospun polycaprolactone-chitosan fibers for use in bisphenol A removal.

Composite polycaprolactone-chitosan material was produced by an electrospinning method and used as a support for immobilization of tyrosinase by mixed ionic interactions and hydrogen bonds formation. The morphology of the fibers and enzyme deposition were confirmed by SEM images. Further, multivariate polynomial regression was used to model the experimental data and to determine optimal conditions for immobilization process, which were found to be pH 7, temperature 25 °C and 16 h process duration. Under these conditions, novel type of biocatalytic system was produced with immobilization yield of 93% and expressed activity of 95%. Furthermore, as prepared system was applied in batch experiments related to biodegradation of bisphenol A under various remediation conditions. It was found that over 80% of the pollutant was removed after 120 min of the process, in the temperature range 15-45 °C and pH 6-9, using solutions at concentration up to 3 mg/L. Experimental data collected proved that the stability and reusability of the tyrosinase were significantly improved upon immobilization: the immobilized biomolecule retained around 90% of its initial activity after 30 days of storage, and was still capable to remove over 80% of bisphenol A even after 10 repeated uses. By contrast, free enzyme was able to remove over 80% of bisphenol A at pH 7-8 and temperature range 15-35 °C, and retained less than 60% of its initial activity after 30 days of storage

Removal of nickel(II) and lead(II) ions from aqueous solution using peat as a low-cost adsorbent: A kinetic and equilibrium study

AbstractAnalysis was carried out to determine the physicochemical characteristics – morphological and structural, electrokinetic properties, elemental composition and functional groups – of peat, with a view to its use as a potential adsorbent of heavy metal ions from aqueous solutions. A significant part of the study comprised tests of adsorption of nickel(II) and lead(II) ions from model solutions. It was determined how the parameters of the adsorption process (time, pH, quantity of sorbent) influence the effectiveness of removal of nickel(II) and lead(II) ions. The adsorption kinetics are also described, using a pseudo-first-order model and pseudo-second-order models of types 1–4. The results show strong correspondence to a pseudo-second-order kinetics model of type 1 (r2=0.999 for all initial concentrations). Another key part of the analysis was the use of the Langmuir and Freundlich models to determine the adsorption isotherms. The experimental data were in strong correspondence with Langmuir’s isotherm model. The sorption capacities of peat with respect to nickel(II) and lead(II) ions were 61.27mg(Ni2+)/g and 82.31mg(Pb2+)/g. Desorption tests confirmed the possibility of reusing peat as an effective sorbent of environmentally harmful metals. A mechanism is also proposed for the adsorption of Ni2+ and Pb2+ ions on adsorbent

A Novel Approach in Crude Enzyme Laccase Production and Application in Emerging Contaminant Bioremediation

Laccase enzyme from white-rot fungi is a potential biocatalyst for the oxidation of emerging contaminants (ECs), such as pesticides, pharmaceuticals and steroid hormones. This study aims to develop a three-step platform to treat ECs: (i) enzyme production, (ii) enzyme concentration and (iii) enzyme application. In the first step, solid culture and liquid culture were compared. The solid culture produced significantly more laccase than the liquid culture (447 vs. 74 µM/min after eight days), demonstrating that white rot fungi thrived on a solid medium. In the second step, the enzyme was concentrated 6.6 times using an ultrafiltration (UF) process, resulting in laccase activity of 2980 µM/min. No enzymatic loss due to filtration and membrane adsorption was observed, suggesting the feasibility of the UF membrane for enzyme concentration. In the third step, concentrated crude enzyme was applied in an enzymatic membrane reactor (EMR) to remove a diverse set of ECs (31 compounds in six groups). The EMR effectively removed of steroid hormones, phytoestrogen, ultraviolet (UV) filters and industrial chemical (above 90%). However, it had low removal of pesticides and pharmaceuticals.</jats:p