scholarly journals A influência do Thiobacillus Thiooxidans na corrosão do aço inoxidável 430 em H2SO4 1 mol L-1

2010 ◽  
Vol 63 (1) ◽  
pp. 97-102 ◽  
Author(s):  
Priscila Anunziato ◽  
Martha Tussolini ◽  
Rebeca Caparica ◽  
Cynthia Beatriz Furstenberger ◽  
Paulo Rogério Pinto Rodrigues
Keyword(s):  
Thiobacillus Thiooxidans

A corrosão microbiológica é um dos grandes problemas industriais da atualidade. O objetivo desse trabalho é estudar a influência da Thiobacillus Thiooxidans (TT) na corrosão do aço inoxidável 430 em H2SO4 1mol L-1. Nesse trabalho, foram empregadas as técnicas de: medidas gravimétricas, polarização anódica potenciostática (PA) e potenciodinâmica cíclica (PC), espectroscopia de impedância eletroquímica (EIE), microscopia óptica e eletrônica de varredura (MEV). Os resultados gravimétricos mostraram que, em 180 minutos de imersão do aço no meio contendo TT, há a formação de biofilme, o qual, inicialmente, bloqueia a corrosão do metal. A PA mostrou que o TT atua catalisando a reação de oxidação do aço 430 nesse meio, sendo que resultados semelhantes foram obtidos pela EIE. A aplicação da PC, na região passiva do aço 430, nesse meio, gera a inibição da geração de biofilmes em sua superfície, resultado este comprovado pela MEV.

scholarly journals THE PRESENCE OF AN ENDOGENOUS RESPIRATION IN THE AUTOTROPHIC BACTERIA

1942 ◽  
Vol 25 (4) ◽  
pp. 617-622 ◽  
Author(s):  
K. G. Vogler
Keyword(s):  
Oxygen Uptake ◽  
Organic Materials ◽  
Endogenous Respiration ◽  
Thiobacillus Thiooxidans ◽  
Autotrophic Bacteria ◽  
Autotrophic Bacterium

It is shown that there exists in the autotrophic bacterium Thiobacillus thiooxidans a measurable oxygen uptake in the absence of the specific nutrient (sulfur). This respiration is shown to be due to the utilization of organic materials which must have been previously synthesized by the chemosynthetic process, providing evidence that autotrophic bacteria contain a dissimilatory process which involves the breakdown of organic materials and furnishes energy for the maintenance of the cell during periods in which the specific nutrient is absent. This is entirely in accord with the work of Bömeke (1939), who provided similar types of proof for Nitrosomonas and Nitrobacter. One may conclude, therefore, that autotrophic bacteria possess an endogenous respiration which involves the utilization of previously synthesized organic materials.

Phosphoenolpyruvate Carboxylase of Thiobacillus thiooxidans. Kinetic and Metabolic Control Properties

1972 ◽  
Vol 50 (2) ◽  
pp. 158-165 ◽  
Author(s):  
R. L. Howden ◽  
H. Lees ◽  
Isamu Suzuki
Keyword(s):  
Enzyme Activity ◽  
Competitive Inhibitor ◽  
Acetyl Coa ◽  
Ph Optimum ◽  
Pep Carboxylase ◽  
Thiobacillus Thiooxidans ◽  
Powerful Activator ◽  
Michaelis Constants ◽  
Noncompetitive Inhibitor ◽  
Decreasing Ph

Phosphoenolpyruvate (PEP) carboxylase (orthophosphate:oxalacetate carboxy-lyase (phosphorylating), EC 4.1.1.31) was purified 19-fold from Thiobacillus thiooxidans. The level of enzyme activity was dependent on culture age. No enzyme activity could be obtained from frozen cells.The pH optimum of the enzyme was determined to be around 8.0. Apparent Michaelis constants were determined for the substrates:phosphoenolpyruvate (1.4, 1.5 mM), bicarbonate (0.4, 1.1 mM), and magnesium (1.1, 0.8 mM) at pH 7.0 and 8.0, respectively. Acetyl-CoA was found to be a powerful activator of this enzyme, with the degree of activation increasing with decreasing pH. The concentration of acetyl-CoA to obtain half-maximal activation, however, remained fairly constant and low, namely 1.2 and 1.0 μM at pH 7.0 and 8.0, respectively. L-Aspartate and L-malate were strong inhibitors of enzyme activity. In the presence of aspartate at pH 7.0 the double reciprocal activity plots for PEP became nonlinear, a characteristic of negative cooperativity. These plots became linear with the addition of acetyl-CoA with aspartate now acting as a noncompetitive inhibitor with respect to PEP. At pH 8.0, the same plots were linear with aspartate acting as a competitive inhibitor of PEP. All the other effectors of PEP carboxylase from Salmonella typhimurium and Escherichia coli were found to be ineffective towards the enzyme from T. thiooxidans.

Corrosion Behavior of Steel A3 Influenced by Thiobacillus Thiooxidans

2009 ◽  
Vol 25 (11) ◽  
pp. 2191-2198
Author(s):  
LI Song-Mei ◽  
◽  
◽  
DU Juan ◽  
LIU Jian-Hua ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
Thiobacillus Thiooxidans

Effect of Various Ions, pH, and Osmotic Pressure on Oxidation of Elemental Sulfur by Thiobacillus thiooxidans

1999 ◽  
Vol 65 (11) ◽  
pp. 5163-5168 ◽  
Author(s):  
Isamu Suzuki ◽  
Douglas Lee ◽  
Byron Mackay ◽  
Lesia Harahuc ◽  
Jae Key Oh
Keyword(s):  
Osmotic Pressure ◽  
Membrane Permeability ◽  
Elemental Sulfur ◽  
Thiobacillus Thiooxidans ◽  
Charge Neutralization ◽  
Potassium Sodium ◽  
Acidophilic Bacterium ◽  
Ph Dependent

ABSTRACT The oxidation of elemental sulfur by Thiobacillus thiooxidans was studied at pH 2.3, 4.5, and 7.0 in the presence of different concentrations of various anions (sulfate, phosphate, chloride, nitrate, and fluoride) and cations (potassium, sodium, lithium, rubidium, and cesium). The results agree with the expected response of this acidophilic bacterium to charge neutralization of colloids by ions, pH-dependent membrane permeability of ions, and osmotic pressure.

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