scholarly journals Direct Electrochemical Generation of Catalytically Competent Oxyferryl Species of Classes I and P Dye Decolorizing Peroxidases

2021 ◽  
Vol 22 (22) ◽  
pp. 12532
Author(s):  
Magalí F. Scocozza ◽  
Lígia O. Martins ◽  
Daniel H. Murgida
Keyword(s):  
Bacillus Subtilis ◽  
Pseudomonas Putida ◽  
Electrochemical Potential ◽  
Class I ◽  
Alkaline Ph ◽  
Electrochemical Generation ◽  
Aerobic Conditions ◽  
High Valent ◽  
Ph Range ◽  
Optimal Ph

This work introduces a novel way to obtain catalytically competent oxyferryl species for two different dye-decolorizing peroxidases (DyPs) in the absence of H2O2 or any other peroxide by simply applying a reductive electrochemical potential under aerobic conditions. UV-vis and resonance Raman spectroscopies show that this method yields long-lived compounds II and I for the DyPs from Bacillus subtilis (BsDyP; Class I) and Pseudomonas putida (PpDyP; Class P), respectively. Both electrochemically generated high valent intermediates are able to oxidize ABTS at both acidic and alkaline pH. Interestingly, the electrocatalytic efficiencies obtained at pH 7.6 are very similar to the values recorded for regular catalytic ABTS/H2O2 assays at the optimal pH of the enzymes, ca. 3.7. These findings pave the way for the design of DyP-based electrocatalytic reactors operable in an extended pH range without the need of harmful reagents such as H2O2.

Comparative Two-Dimensional Gel Electrophoresis of Trypanosoma cruzi Mammalian-Stage Forms in an Alkaline pH Range

2015 ◽  
Vol 22 (12) ◽  
pp. 1066-1075 ◽  
Author(s):  
Adriana Magalhães ◽  
Rayner Queiroz ◽  
Izabela Bastos ◽  
Jaime Santana ◽  
Marcelo Sousa ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Gel Electrophoresis ◽  
Two Dimensional ◽  
Alkaline Ph ◽  
Two Dimensional Gel Electrophoresis ◽  
Ph Range

scholarly journals Effect of alkaline pH on photosynthetic water oxidation and the association of extrinsic proteins with Photosystem Two

1989 ◽  
Vol 258 (2) ◽  
pp. 357-362 ◽  
Author(s):  
D J Chapman ◽  
J De Felice ◽  
K Davis ◽  
J Barber
Keyword(s):  
Water Splitting ◽  
Water Oxidation ◽  
Binding Sites ◽  
Partial Recovery ◽  
Alkaline Ph ◽  
Ph Values ◽  
Extrinsic Proteins ◽  
Reversible Phase ◽  
Photosynthetic Water Oxidation ◽  
Optimal Ph

Incubation of a membrane preparation enriched in Photosystem Two (PSII) at alkaline pH inhibited the water-splitting reactions in two distinct steps. Up to pH 8.5 the inhibition was reversible, whereas at higher alkalinities it was irreversible. It was shown that the reversible phase correlated with loss and rebinding of the 23 kDa extrinsic polypeptide. However, after mild alkaline treatments a partial recovery was possible without the binding of the 23 kDa polypeptide when the assay was at the optimal pH of 6.5 and in a medium containing excess Cl-. The irreversible phase was found to be closely linked with the removal of the 33 kDa extrinsic protein of PSII. Treatments with pH values above 8.5 not only caused the 33 kDa protein to be displaced from the PSII-enriched membranes, but also resulted in an irreversible modification of the binding sites such that the extrinsic 33 kDa protein could not reassociate with PSII when the pH was lowered to 6.5. The results obtained with these more extreme alkaline pH treatments support the notion that the 23 kDa protein cannot bind to PSII unless the 33 kDa protein is already bound. The differential effect of pH on the removal of the 23 kDa and 33 kDa proteins contrasted with the data of Kuwabara & Murata [(1983) Plant Cell Physiol. 24, 741-747], but this discrepancy was accounted for by the use of glycerol in the incubation media.

Effect of temperature and pH on the production, activity, and stability of α-amylase from Bacillus subtilis V37

2021 ◽  
Vol 66 (1) ◽  
pp. 72-79
Author(s):  
Thuoc Doan Van ◽  
Hung Nguyen Phuc
Keyword(s):  
Enzyme Activity ◽  
Bacillus Subtilis ◽  
Animal Feed ◽  
Culture Conditions ◽  
Effect Of Temperature ◽  
Physical Parameters ◽  
Original Activity ◽  
Optimum Ph ◽  
Production Activity ◽  
Ph Range

The effect of physical parameters such as temperature and pH on the production, activity, and stability of α-amylase from Bacillus subtilis V37 was investigated. The results indicated that the optimum culture conditions for enzyme activity were pH 7.0 and 35 oC. The optimum pH and temperature for enzyme activity were 6.0 and 70 oC. The crude enzyme was found to be stable in the pH range of 5.0 to 7.0. The enzyme was stable for 1 h at a temperature from 30 to 80 oC; nearly 100% of enzyme activity remained at temperatures of 30 - 40 oC, and about 34% of original activity remained at a temperature of 80 oC. These features demonstrated that α-amylase from B. subtilis V37 can be applied in many areas such as the food, fermentation, and animal feed industries.

scholarly journals Rizobacterias con potencial antagonista in vitro a Mycosphaerella fijiensis Morelet

2020 ◽  
Vol 13 (2) ◽  
Author(s):  
Karen Tatiana Chávez Arteaga ◽  
Jefferson Javier Guato Molina ◽  
Jorge Luis Rodríguez Acosta ◽  
Ángel Virgilio Cedeño Moreira ◽  
Ricardo Fernando Romero Meza ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Pseudomonas Putida ◽  
Serratia Marcescens ◽  
Pseudomonas Fluorescens ◽  
Mycosphaerella Fijiensis ◽  
Subtilis Atcc ◽  
Bacillus Subtilis Atcc ◽  
Pseudomonas Veronii ◽  
Enterobacter Asburiae

El empleo de bio-controladores en la agricultura beneficia los aspectos fisiológicos en plantas, a diferencia de la constante aplicación de pesticidas en el cultivo del banano ha ocasionado la pérdida de la sensibilidad en M. fijiensis, reduciendo la microbiota del suelo. El objetivo se enfocó en caracterizar el potencial antagónico de las PGPR en inhibición de germinación de ascósporas y desarrollo micelial de M. fijiensis. Se realizaron cultivos monospóricos de M. fijiensis e identificado por PCR. Se evaluaron los extractos celulares de Pseudomonas putida PB3-6, Klebsiella variicola BO3-4, Enterobacter asburiae BA4-19, Serratia marcescens PM3-8, Enterobacter asburiae PM3-14, Pseudomonas protegens CHA0, Pseudomonas fluorescens WCS417, Pseudomonas veronii R4 y Bacillus subtilis ATCC 5540 para sus evaluaciones antagonistas: a) Inhibición del tubo germinativo de las ascósporas al 2% y b) Desarrollo micelial al (2 y 10 %). La PCR empleado en la identificación de M. fijiensis se confirma el producto de amplificación de 1018 pb. El factor antagónico de los extractos celulares al 2 % de PM3-14 y CHA0 inhibe sobre el 80 % al desarrollo de los tubos germinativos. La inhibición al desarrollo micelial del extracto celular al 2 %, de CHA0 logró una efectividad del 54 % y las cepas (PM3-8, PM3-14 y BA4-19) con (32, 26 y 26 %). Al 10 % del extracto de la cepa PM3-8 inhibe el desarrollo micelial con niveles de turbidez de 0,47 (OD600nm). El empleo de estos bio-controladores en la agricultura ofrecerá una alternativa para beneficiar en la reducción del uso de agroquímicos

scholarly journals Optimal pH in chlorinated swimming pools – balancing formation of by-products

2013 ◽  
Vol 11 (3) ◽  
pp. 465-472 ◽  
Author(s):  
Kamilla M. S. Hansen ◽  
Hans-Jørgen Albrechtsen ◽  
Henrik R. Andersen
Keyword(s):  
Body Fluid ◽  
Product Formation ◽  
Swimming Pools ◽  
Batch Experiments ◽  
Ph Values ◽  
Precursor Ratio ◽  
Decreasing Ph ◽  
Ph Range ◽  
By Products ◽  
Optimal Ph

In order to identify the optimal pH range for chlorinated swimming pools, the formation of trihalomethanes, haloacetonitriles and trichloramine was investigated in the pH-range 6.5–7.5 in batch experiments. An artificial body fluid analogue was used to simulate bather load as the precursor for by-products. The chlorine-to-precursor ratio used in the batch experiments influenced the amounts of by-products formed, but regardless of the ratio the same trends in the effect of pH were observed. Trihalomethane formation was reduced by decreasing pH, but haloacetonitrile and trichloramine formation increased. To evaluate the significance of the increase and decrease of the investigated organic by-products at the different pH values, the genotoxicity was calculated based on literature values. The calculated genotoxicity was approximately at the same level in the pH range 6.8–7.5 and increased when pH was 6.7 or lower. An optimal pH range for by-products formation in swimming pools was identified at pH 7.0–7.2. In the wider pH range (pH 6.8–7.5), the effect on by-product formation was negligible. Swimming pools should never be maintained at lower pH than 6.8 since formation of both haloacetonitriles and trichloramine increase significantly below this value.

scholarly journals Studies on poly-3-hydroxyoctanoate biosynthesis by a consortium of microorganisms

2016 ◽  
Vol 27 (1) ◽  
pp. 44-47 ◽  
Author(s):  
Mihaela Carmen Eremia ◽  
Irina Lupescu ◽  
Mariana Vladu ◽  
Maria Petrescu ◽  
Gabriela Savoiu ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Carbon Source ◽  
Pseudomonas Putida ◽  
Sole Carbon Source ◽  
Bacterial Biomass ◽  
Fermentation Medium ◽  
Energy Reserve ◽  
Bacterial Strains ◽  
Sodium Octanoate ◽  
Intracellular Energy

Abstract Polyhydroxyalcanoates (PHAs) are specifically produced by a wide variety of bacteria, as an intracellular energy reserve in the form of homo- and copolymers of [R]-β-hydroxyalkanoic acids, depending on the C source used for microorganism growth, when the cells are grown under stressing conditions. In this paper we present microbiological accumulation of poly-3-hydroxyoctanoate (PHO) by using a consortium of bacterial strains, Pseudomonas putida and Bacillus subtilis, in a rate of 3:1, grown on a fermentation medium based on sodium octanoate as the sole carbon source. The experiments performed in the above mentioned conditions led to the following results: from 18.70 g sodium octanoate (7.72 g/L in the fermentation medium) used up during the bioprocess, 3.93-3.96 g/L dry bacterial biomass and 1.834 - 1.884 g/L PHA, containing 85.83 - 86.8% PHO, were obtained.

scholarly journals Flotation Behavior of Diatomite and Albite Using Dodecylamine as a Collector

Minerals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 371 ◽  
Author(s):  
Ying Gao ◽  
Yuexin Han ◽  
Wenbo Li
Keyword(s):  
Unit Area ◽  
Alkaline Ph ◽  
Force Microscopy ◽  
Atomic Force ◽  
Mineral Flotation ◽  
Alkaline Conditions ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Ph Range ◽  
First Time

The flotation behaviors of diatomite and albite using dodecylamine (DDA) as a collector were investigated and compared. The pure mineral flotation results indicate that the flotability difference between albite and diatomite is above 87% at pH 5.5 to 10.5. The recovery of albite improves with increasing DDA dosage at pH 5.5 to 10.5. In the same pH range, diatomite has weaker flotability than albite, particularly in alkaline pH pulp. Zeta potential measurements indicate that diatomite has a higher negative surface charge than albite at pH 7 to 12, DDA interacts strongly with albite and weakly with diatomite. Thus, DDA preferentially absorbs on albite surface rather than diatomite under alkaline conditions. Fourier transform infrared spectra (FTIR) indicate that the amount of DDA adsorbed to albite is greater than that adsorbed to diatomite, under the same conditions. The adsorption of DDA on the surface of diatomite is investigated by using atomic force microscopy (AFM) for the first time. The adsorption of the collector DDA on the surface of albite per unit area is greater than that on diatomite. This accounts for the lower recovery of diatomite than that of albite.

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