Modeling and simulation of the enzymatic degradation of 2,4,6-trichlorophenol using soybean peroxidase

The enzymatic degradation of organic pollutants is a promising and ecological method for the remediation of industrial effluents. 2,4,6-Trichlorophenol is a major pollutant in many residual waters, and its consumption has been linked to lymphomas, leukemia, and liver cancer. The goal of the present work is to comprehend the enzymatic degradation of 2,4,6-trichlorophenol using soybean peroxidase. Different assumptions for the kinetic model were evaluated, and the simulations were compared to experimental data, which was obtained in a microreactor. The literature pointed out that the bi-bi ping-pong model represents well the kinetics of soybean peroxidase degradation. Since it is a complex model, some reactions can be considered or not. Six different possibilities for the model were considered, regarding different combinations of the generated enzyme forms that depend on the hypotheses for simplifying the model. The adjustment of the models was compared based on different metrics, such as the value of the objective function, coefficient of determination and root-mean-square error. The process modeling was obtained by the mass balance of all the reaction components, and all the simulations were performed in MATLAB® R2015a. Reaction parameters were estimated based on the weighted least squares between the experimental data set and the values predicted by the model. The results showed that the data were better adjusted by the model that considers all the enzyme forms, including enzyme inactivation. Therefore, a better comprehension of the reaction mechanism was achieved, which allows a more precise reactor project and process simulation.

Immobilized Soybean Peroxidase Hybrid Biocatalysts for Efficient Degradation of Various Emerging Pollutants

In the present study, soybean peroxidase (SBP) was covalently immobilized onto two functionalized photocatalytic supports (TiO2 and ZnO) to create novel hybrid biocatalysts (TiO2-SBP and ZnO-SBP). Immobilization caused a slight shift in the pH optima of SBP activity (pH 5.0 to 4.0), whereas the free and TiO2-immobilized SBP showed similar thermal stability profiles. The newly developed hybrid biocatalysts were used for the degradation of 21 emerging pollutants in the presence and absence of 1-hydroxy benzotriazole (HOBT) as a redox mediator. Notably, all the tested pollutants were not equally degraded by the SBP treatment and some of the tested pollutants were either partially degraded or appeared to be recalcitrant to enzymatic degradation. The presence of HOBT enhanced the degradation of the pollutants, while it also inhibited the degradation of some contaminants. Interestingly, TiO2 and ZnO-immobilized SBP displayed better degradation efficiency of a few emerging pollutants than the free enzyme. Furthermore, a combined enzyme-chemical oxidation remediation strategy was employed to degrade two recalcitrant pollutants, which suggest a novel application of these novel hybrid peroxidase-photocatalysts. Lastly, the reusability profile indicated that the TiO2-SBP hybrid biocatalyst retained up to 95% degradation efficiency of a model pollutant (2-mercaptobenzothiazole) after four consecutive degradation cycles.

Stabilization of paper waste in bioreactor landfills using soybean peroxidase enzyme

One obvious way to reduce the amount of paper waste being discarded, and to conserve the forest resources, is to recycle more of the waste paper. But most common waste management technique for solid waste is the use of landfills. This study was aimed at decomposing the waste in aerobic condition before the anaerobic condition using soybean peroxidase enzyme (SBP). One bioreactor cell without enzyme was compared with two bioreactor cells, which contained different concentration of soybean peroxidase enzyme with hydrogen peroxide (H₂O₂). The rate of reaction was analyzed by performing COD, BOD₅, NH₃, TS and pH tests as well as monitoring the settlement. The findings showed that the bioreactors with enzyme had faster decomposition rate than the control one. Final COD concentration in control one was 62.6% higher than the bioreactor having higher concentrations of enzyme. Similarly, final BOD₅ concentration in control one was 70.7% higher than the bioreactor having higher concentration of enzyme. Furthermore, the results were compared with the previous study, the bioreactors having municipal solid waste (MSW) with biosolids. The results showed that the strength of leachate quality was much better in bioreactors having paper waste with enzyme than the bioreactor having MSW with biosolids. The COD reduction rate in case of enzyme was about more than double than the bioreactor having biosolids. Similarly, BOD₅ reduction rate in case of enzyme was 1.6 times higher than the biosolids and TS reduction rate was about 1.4 times higher than the bioreactor having biosolids.

Stabilization of paper waste in bioreactor landfills using soybean peroxidase enzyme

One obvious way to reduce the amount of paper waste being discarded, and to conserve the forest resources, is to recycle more of the waste paper. But most common waste management technique for solid waste is the use of landfills. This study was aimed at decomposing the waste in aerobic condition before the anaerobic condition using soybean peroxidase enzyme (SBP). One bioreactor cell without enzyme was compared with two bioreactor cells, which contained different concentration of soybean peroxidase enzyme with hydrogen peroxide (H₂O₂). The rate of reaction was analyzed by performing COD, BOD₅, NH₃, TS and pH tests as well as monitoring the settlement. The findings showed that the bioreactors with enzyme had faster decomposition rate than the control one. Final COD concentration in control one was 62.6% higher than the bioreactor having higher concentrations of enzyme. Similarly, final BOD₅ concentration in control one was 70.7% higher than the bioreactor having higher concentration of enzyme. Furthermore, the results were compared with the previous study, the bioreactors having municipal solid waste (MSW) with biosolids. The results showed that the strength of leachate quality was much better in bioreactors having paper waste with enzyme than the bioreactor having MSW with biosolids. The COD reduction rate in case of enzyme was about more than double than the bioreactor having biosolids. Similarly, BOD₅ reduction rate in case of enzyme was 1.6 times higher than the biosolids and TS reduction rate was about 1.4 times higher than the bioreactor having biosolids.

Biocatalytic oligomerization of azoles; experimental and computational studies

Soybean peroxidase effectively transformed selected amino- and hydroxyl-azoles by radical coupling to dimers and trimers, showing feasibility for wastewater treatment.

Soybean peroxidase treatment of ultra-high kappa softwood pulp to enhance yield and physical properties

The working hypothesis serving as basis for this study is that pulping to a higher kappa number will produce a higher yield pulp, and then treating that pulp with a surface reactive lignin peroxidase to ablate surface lignin will increase specific bonding area. In the present case, the working hypothesis was modified so that soybean peroxidase (SBP) works like lignin peroxidase to modify surface lignin on high-kappa, high-yield softwood pulps to facilitate enhanced fiber-to-fiber bonding such that the resulting paper strength is similar to the lower kappa soft-wood pulp generally used to make linerboard. Soybean peroxidase is actually a plant peroxidase that exhibits lignin peroxidase-like activity. It is not a lignin peroxidase derived from white rot fungus. The current work did show a significant improvement in pulp yield (62.2% vs. 55.2% yield for a 103-kappa control linerboard grade sheet), while treatment with SBP showed that tensile, burst, and STFI properties of the pulp were improved, although more convincing data needs to be obtained.