Effect of C/N Ratio and Physicochemical Conditions on the production of Rhamnolipids by Pseudomonas Aeruginosa LBI

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Wettability of Aqueous Rhamnolipids Solutions Produced by Pseudomonas aeruginosa LBI

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cassava wastewater as a substrate for the simultaneous production of rhamnolipids and polyhydroxyalkanoates by Pseudomonas aeruginosa

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Rhamnolipids and PHAs: Recent reports on Pseudomonas-derived molecules of increasing industrial interest

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Factors affecting rhamnolipids production by Pseudomonas aeruginosa LBI

This paper presents the results from study investigating the capacity of Pseudomonas aeruginosa LBI growing on several carbon (Hydrophilic substrate) and nitrogen sources. The carbon source (2016) studied were: glycerol, manitol, fructose, glucose, lactose and the nitrogen sources (2; 3; 4 and 5016) were: NaNO3, NH4NO3, (NH4)(2)SO4 and (NH2)(2)CO. At the 96 h of fermentation, the medium with glycerol as a carbon source reached 7.9 g/L of rhamnolipids and 1. 2 g/L cellular protein. The surface tension reduction was 38.46 % for glycerol as a carbon source. The NaNO3 at 3% was the best concentration for rhamnolipids production (7.35 g/L) and cellular protein (1.12 g/L). The influences of metal ions [FeSO4.7H(2)O (0.001g/L, 0.005 g/L and 0.1 g/L) and MgSO4.7H(2)O (0.001 g/L, 0.005 g/L and 0.1 g/L)] on ramnolipids production were studied. Fe2+ had a negative influence on the studied concentrations while Mg2+ had a positive influence when its concentration was increased.

Synergistic effect in the catalytic activity of lipase Rhizomucor miehei immobilized on zeolites for the production of biodiesel

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Structure of 2-keto-3-deoxy-6-phosphogluconate (KDPG) aldolase from Pseudomonas putida

2-Keto-3-deoxy-6-phosphogluconate (KDPG) aldolase from Pseudomonas putida is a key enzyme in the Entner-Doudoroff pathway which catalyses the cleavage of KDPG via a class I Schiff-base mechanism. The crystal structure of this enzyme has been refined to a crystallographic residual R = 17.1% (R-free = 21.4%). The N-terminal helix caps one side of the torus of the (betaalpha)(8)-barrel and the active site is located on the opposite, carboxylic side of the barrel. The Schiff-base-forming Lys145 is coordinated by a sulfate (or phosphate) ion and two solvent water molecules. The interactions that stabilize the trimer are predominantly hydrophobic, with the exception of the cyclically permuted bonds formed between Glu132 OE1 of one molecule and Thr129 OG1 of a symmetry-equivalent molecule. Except for the N-terminal helix, the structure of KDPG aldolase from P. putida closely resembles the structure of the homologous enzyme from Escherichia coli.

Effect of surfactants and polyethylene glycol on the activity and stability of a lipase from oilseeds of Pachira aquatica

Lipases from oilseeds have a great potential for commercial exploration as industrial enzymes. Lipases are used mixed with surfactants in cleaning and other formulated products, and accordingly, both components must be compatible with each other. This work presents the results of the effects of anionic, cationic and nonionic surfactants, polyethylene glycol and urea on the activity and stability of a lipase extracted of oilseeds from Pachira aquatica. The enzyme was purified and the spectrophotometric assays were done using p-nitrophenyl acetate (p-NPA) as substrate pH 7.5 and 25 degrees C. The activity was significantly enhanced by the cationic surfactant CTAB. Bile salts increased the lipase activity in the tested concentration range, whereas anionic and nonionic surfactants showed an inhibitory effect. Aqueous solutions of PEG activated the lipase and maximum activation (161%) occurred in PEG 12,000. This effect on lipase that can be due to exposition of some hydrophobic residues located in the vicinity of the active site or aggregation.

A new lipase isolated from oleaginous seeds from Pachira aquatica (Bombacaceae)

A new lipase from seeds of Pachira aquatica was purified to homogeneity by SDS-PAGE obtaining an enzyme with a molecular weight of approximately 55 kDa. The purified lipase exhibited maximum activity at 40 degrees C and pH 8.0, for an incubation time of 90 min. Concerning temperature stability, at the range from 4 to 50 degrees C, it retained approximately 47% of its original activity for 3 h. The enzyme activity increased in the presence of Ca(++) and Mg(++), but was inhibited by Hg(++), Mn(++), Zn(++), Al(+++) and various oxidizing and reducing agents. The lipase was highly stable in the presence of organic solvents, and its activity was stimulated by methanol. The values of K(m) and V(max) were 1.65 mM and 37.3 mu mol mL(-1) min(-1), respectively, using p-nitrophenylacetate as substrate. The enzyme showed preference for esters of long-chain fatty acids, but demonstrated significant activity against a wide range of substrates.

Gama de hospedeiros e reação de genótipos de tomateiro a Pseudomonas cichorii

Em 2005, foi constatada em dois campos comerciais de tomate no Estado de São Paulo, a ocorrência da queima bacteriana, causada por Pseudomonas cichorii. em vista disso, foram desenvolvidos estudos visando a determinação da gama de hospedeiros de isolados de Pseudomonas cichorii (IBSBF 2309 e IBSBF 2323), obtidos de tomateiro, provenientes de campos comerciais localizados nos municípios de Bragança Paulista e Mogi Guaçú, SP. Plantas de abobrinha, alface, beldroega, berinjela, beterraba, cenoura, couvebrócolo, datura, fumo, girassol, jiló, melão, pepino, petúnia, pimentão, rabanete, repolho, rúcula, salsa e tomateiro foram inoculadas por pulverização, separadamente, com os dois isolados de P. cichorii de tomateiro e um isolado de girassol (GIR-1). Os isolados IBSBF 2309 e IBSBF 2323 foram patogênicos à beldroega, datura, girassol, pimentão e tomate; GIR-1 foi patogênico apenas à beldroega, datura e girassol, não sendo patogênico ao pimentão e ao tomateiro. No Brasil não se conhecem fontes de resistência dentro do gênero Lycopersicon ou a reação de cultivares de tomateiros a esta bactéria. Vinte e oito genótipos de tomateiro provenientes do Banco de Germoplasma da empresa Sakata Seed Sudamerica Ltda., foram avaliados quanto a reação aos isolados IBSBF 2309 e IBSBF 2323 de P. cichorii, pelo método de inoculação nas folhas. Os maiores níveis de resistência foram observados em AF 11768, AF 2521, AF 11766, AF 11772, AF 229, AF 5719-1 e AF 8162. O genótipo AF 5719-1, que possui o gene Pto, que confere resistência a P. syringae pv. tomato, apresentou um bom nível de resistência a P. cichorii. A identificação de genótipos que apresentem bons níveis de resistência a este patógeno é importante para utilização em programas de melhoramento genético do tomateiro, visando a incorporação de genes de resistência a P. cichorii.

Controle biológico da podridão radicular (Pythium aphanidermatum) e promoção de crescimento por Pseudomonas chlororaphis 63-28 e Bacillus subtilis GB03 em alface hidropônica

Podridões radiculares causadas por espécies de Pythium são um importante problema em cultivos hidropônicos. Sintomas de subdesenvolvimento são observados nas plantas parasitadas pelo patógeno, sendo muitas vezes não diagnosticados pelo produtor. O objetivo do trabalho foi avaliar o controle biológico da podridão radicular causada por Pythium aphanidermatum e a promoção de crescimento por Pseudomonas chlororaphis 63-28 e Bacillus subtilis GB03, reconhecidos agentes de controle biológico de doenças de plantas. A inoculação das plantas com P. aphanidermatum ocasionou o subdesenvolvimento, sendo essa diminuição de 20%. A adição dos agentes de biocontrole na solução nutritiva teve um efeito positivo no aumento da massa (6% a 13%), no número de folhas (4% a 7%) e no teor de clorofila (3%) das plantas de alface. Entretanto, maiores estudos devem ser realizados para melhorar a capacidade de controle da doença e de promoção de crescimento pelos agentes de biocontrole estudados no cultivo de alface hidropônica.

Tris-EDTA no teste de sensibilidade antimicrobiana in vitro em amostras de Pseudomonas aeruginosa

In vitro antimicrobial susceptibility of strains of Pseudomonas aeruginosa by standard diffusion disk test and a modified method, by the addition Tris-EDTA, was evaluated. Increase in sensitivity of agent using modified method was observed mainly in aminoglycosides (amikacin, gentamicin, tobramycin), quinolones (ofloxacin and norfloxacin) and cephalosporins (cefoperazone and ceftazidime) groups. by standard diffusion disk test and a modified method, by the addition Tris-EDTA, was evaluated. Increase in sensitivity of agent using modified method was observed mainly in aminoglycosides (amikacin, gentamicin, tobramycin), quinolones (ofloxacin and norfloxacin) and cephalosporins (cefoperazone and ceftazidime) groups.

Modified E-test by the addition of EDTA-Tris and dimethyl sulfoxide on the potentiation of the effects of some antimicrobials in Pseudomonas aeruginosa strains isolated from bovine mastitis

A concentração inibitória mínima-MIC em 30 estirpes de Pseudomonas aeruginosa isoladas de mastite bovina foi avaliada utilizando o E-test padrão e o método modificado, pela adição de Tris-EDTA e DMSO. Os métodos modificados apresentaram redução significativa da MIC das estirpes utilizando a gentamicina, a ciprofloxacina e a norfloxacina.

Production of Pseudomonas aeruginosa LBI rhamnolipids following growth on Brazilian native oils

Oils from Buriti (Mauritia flexuosa), Cupuacu (Theobroma grandiflora), Passion Fruit (Passiflora alata), Andiroba (Carapa gitianensis), Brazilian Nut (Bertholletia excelsa) and Babassu (Orbignya spp.) were evaluated as carbon sources for rhamnolipid production by Pseudomonas aeruginosa LBI. The highest rhamnolipid concentrations were obtained from Brazilian Nut (9.9 l(-1)) and Passion Fruit (9.2 g l(-1)) oils. Surface tension varied from 29.8 to 31.5 mN m(-1), critical micelle concentration from 55 to 163 mg l(-1) and the emulsifying activity was higher against toluene (93-100%) than against kerosene (70-92%). Preliminary characterization of the surfactant mixtures by mass spectrometry revealed the presence of two major components showing m/z of 649 and 503, which corresponded to the dirhamnolipid (Rha(2)C(10)C(10)) and the monorhamnolipid (RhaC(10)C(10)), respectively. The monorhamnolipid detected as the ion of m/z 503 is predominant in all samples analyzed. (c) 2005 Elsevier Ltd. All rights reserved.