Enhancing inulinase yield by irradiation mutation associated with optimization of culture conditions

A new inulinase-producing strain was isolated from rhizosphere soils of Jerusalem artichoke collected from Shihezi (Xinjiang, China) using Jerusalem artichoke power (JAP) as sole carbon source. It was identified as an Aspergillus niger strain by analysis of 16S rRNA. To improve inulinase production, this fungus was subjected to mutagenesis induced by ⁶⁰Co γ-irradiation. A genetically stable mutant (designated E12) was obtained and it showed 2.7-fold higher inulinase activity (128 U/mL) than the parental strain in the supernatant of a submerged culture. Sequential methodology was used to optimize the inulinase production of stain E12. A screening trial was first performed using Plackett-Burman design and variables with statistically significant effects on inulinase bio-production were identified. These significant factors were further optimized by central composite design experiments and response surface methodology. Finally, it was found that the maximum inulinase production (185 U/mL) could be achieved under the optimized conditions namely pH 7.0, yeast extract concentration of 5.0 g/L, JAP concentration of 66.5 g/L, peptone concentration of 29.1 g/L, solution volume of 49.4 mL in 250-mL shake flasks, agitation speed of 180 rpm, and fermentation time of 60 h. The yield of inulinase under optimized culture conditions was approximately 1.4-fold of that obtained by using basal culture medium. These findings are of significance for the potential industrial application of the mutant E12.

Ethnic Coefficients for Glomerular Filtration Rate Estimation by the Modification of Diet in Renal Disease Study Equations in the Korean Population

Race and ethnicity are influential in estimating glomerular filtration rate (GFR). We aimed to find the Korean coefficients for the Modification of Diet in Renal Disease (MDRD) study equations and to obtain novel proper estimation equations. Reference GFR was measured by systemic inulin clearance. Serum creatinine (SCr) values were measured by the alkaline picrate Jaffe kinetic method, then, recalibrated to CX3 analyzer and to isotope dilution mass spectrometry (IDMS). The Korean coefficients for the 4 and 6 variable MDRD and IDMS MDRD study equations based on the SCr recalibrated to CX3 and to IDMS were 0.73989/0.74254 and 0.99096/0.9554, respectively. Coefficients for the 4 and 6 variable MDRD equations based on the SCr measured by Jaffe method were 1.09825 and 1.04334, respectively. The modified equations showed better performances than the original equations. The novel 4 variable equations for Korean based on the SCr measured and recalibrated to IDMS were 107.904xSCr-1.009xage-0.02 (x0.667, if woman) and 87.832xSCr-0.882xage0.01 (x0.653, if woman), respectively. Modified estimations of the MDRD and IDMS MDRD study equations with ethnic coefficients and the novel equations improve the performance of GFR estimation for the overall renal function.

Identification and characterization of filamentous fungi isolated from the sunflower (Helianthus annus L. ) rhizosphere according to their capacity to hydrolyse inulin

Fungos filamentosos capazes de hidrolisar inulina tem sido isolados de rizosfera de plantas que acumulam esse polissacarídeo nas raízes. Este estudo compreendeu o isolamento e identificacão de fungos filamentosos do solo utilizado para o cultivo do girassol e da rizosfera de girassol cultivado em campo e em casa de vegetacão, a fim de verificar se há variacão na diversidade destes fungos ao longo do ciclo de vida da planta. O fungos foram também caracterizados quanto a capacidade de hidrolisar inulina. Das quarenta e nove espécies de fungos filamentosos isoladas, Penicillium e Aspergillus foram os gêneros que apresentaram maior número de espécies, nove e sete, respectivamente. No final do ciclo de vida do girassol, cultivado tanto em campo quanto em casa de vegetacão, foi isolado um menor número de espécies. Cento e cinquenta e nove amostras de fungos filamentosos, isoladas do solo e da rizosfera de girassol e destas 79 (49,7 per center) foram capazes de hidrolisar inulina. Não houve diferenca significativa quanto a proporcão de espécies capazes ou não de hidrolisar esse polissacarídeo, ao longo do ciclo de vida do girassol, cultivado tanto em campo quanto em casa de vegetacão. Embora a rizosfera de girassol seja uma fonte de fungos filamentosos capazes de hidrolisar inulina, que podem ser utilizados em processos biotecnológicos, ela não atua de modo a concentrar fungos com esta característica. Espécies de Aspergillus, Chaetomium, Cunninghamella, Emericela, Eupenicillium, Fusarium, Myrothecium, Neosartorya, Neocosmospora, Penicillium and Thielavia estão sendo relatados pela primeira vez como produtores de inulinase.

Production and action pattern of inulinase from "Aspergillus niger"-245: hydrolysis of innulin from several sources

A strain of Aspergillus niger isolated from soil samples showed great capacity to produce extracellular inulinase. Although the enzyme has been synthesized in presence of monosaccharides, sucrose and sugar cane molasse, the productivity was significantly higher (p<0.05) when the microorganism was inoculated in media formulated with dahlia extract and pure inulin, as carbon sources. With regard to the nitrogen source, the best results were obtained with casein and other sources of proteic nitrogen, comparatively to the mineral nitrogen. However, statistic significance (p<0.01) only was found between the productivity obtained in the medium prepared with casein amonium sulphate. The optimum pH of the purified enzyme for inulin hydrolysis was found between 4.0 and 4.5 and the optimum tempereature at 60ºC. When treated by 30 minutes u=in this temperature no loss of activity was observed. The enzyme showed capacity to hydrolyse sucrose, raffinose and inulin from which it liberated only fructose units showing, therefore, an exo-action mechanism. Acting on inulins from several sources, the enzyme showed larger hydrolysis speed on the polissaccharide from chicory ("Cichorium intibus"), comparatively, to the inulins from dahlia ("Dahlia pinnata") and Jerusalem astichoke ("Helianthus tuberosus") roots.

The renal effects of kainic acid

the respone of juvenile cultivated Piaractus mesopotamicus to handling stress, whthout anesthesia, was determined over 3-5 min (T1), 1 h (T2) and 6 h (T3) afeter capture. Plasma cortisol, glucose and total cholesterol were measured. Hyperglycemia present at T2 continued to rise until T3 while plasma cortisol levels increased but were similar at T2 and T3. Total plasma cholesterol was altered only at T3. Hyperglycemic changes were greater in fish without than stomach contents during the T2-T3 period. These differences in hyperglycemic changes may reflect the role of hormones other than cortisol in the regulation of glucose release in these fish