Evidence of high production levels of thermostable dextrinizing and saccharogenic amylases by Aspergillus niveus

The aim of this work was to analyze the effect of several nutritional and environmental parameters on amylase production by a novel, isolated from the thermotolerant filamentous fungus Aspergillus niveus. This strain produced high levels of amylolytic activity in Khanna liquid medium supplemented with commercial starch, initial pH 6.5, under static conditions for 72 h. Among the tested carbon sources, milled corn, oatmeal, soluble potato starch and maisena were the best inducers of enzymatic secretion (220, 180, 170 and 150 U/mL), respectively. The main products of hydrolysis analyzed by thin layer chromatography were glucose, maltose and traces of maltooligosaccharides, suggesting the presence of α-amylase and glucoamylase activities in the crude extract. The optimal pH were 4.5 and 5.5 and the optimum temperature was 65°C. The enzymes were fully stable up to 1 h at 55°C. It was possible to verify the presence of three bands with amylolytic activity in non-denaturing polyacrylamide gel electrophoresis (PAGE). These aspects and other properties suggested that the amylases produced by A. niveus might be suitable for biotechnological applications.KKeywords: Starch, α-amylase, glucoamylase, Aspergillus niveus, submerged fermentation, thermostabilityAfrican Journal of Biotechnology Vol. 12(15), pp. 1874-188

Biotechnological potential of alternative carbon sources for production of pectinases by Rhizopus microsporus var. rhizopodiformis

Fungi collected from Brazilian soil and decomposing plants were screened for pectinase production. R. microsporus var. rhizopodiformis was the best producer and was selected to evaluate the pectic enzyme production under several nutritional and environmental conditions. The pectinase production was studied at 40ºC, under 28 carbon sources-supplemented medium. The inducer effect of several agro-industrial residues such as sugar cane bagasse, wheat flour and corncob on polygalacturonase (PG) activity was 4-, 3- and 2-fold higher than the control (pectin). In glucose-medium, a constitutive pectin lyase (PL) activity was detected. The results demonstrated that R. microsporus produced high levels of PG (57.7 U/mg) and PL (88.6 U/mg) in lemon peel-medium. PG had optimum temperature at 65 ºC and was totally stable at 55 ºC for 90 min. Half-life at 70 ºC was 68 min. These results suggested that the versatility of waste carbon sources utilization by R. microsporus, produce pectic enzymes, which could be useful to reduce production costs and environmental impacts related to the waste disposal.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)(CNPq) Conselho de Desenvolvimento Científico e Tecnológic

Biotechnological Potential of Agro-Industrial Wastes as a Carbon Source to Thermostable Polygalacturonase Production in Aspergillus niveus

Agro-industrial wastes are mainly composed of complex polysaccharides that might serve as nutrients for microbial growth and production of enzymes. The aim of this work was to study polygalacturonase (PG) production by Aspergillus niveus cultured on liquid or solid media supplemented with agro-industrial wastes. Submerged fermentation (SbmF) was tested using Czapeck media supplemented with 28 different carbon sources. Among these, orange peel was the best PG inducer. On the other hand, for solid state fermentation (SSF), lemon peel was the best inducer. By comparing SbmF with SSF, both supplemented with lemon peel, it was observed that PG levels were 4.4-fold higher under SSF. Maximum PG activity was observed at 55°C and pH 4.0. The enzyme was stable at 60°C for 90 min and at pH 3.0–5.0. The properties of this enzyme, produced on inexpensive fermentation substrates, were interesting and suggested several biotechnological applications

Variação genética para compostos bioquímicos em sementes de uma população natural de Luehea divaricata Mart.

Espécies arbóreas, pelo seu grande porte e longevidade, são os organismos chaves dos ecossistemas florestais. Dentre as espécies florestais no Brasil, encontra-se a açoita-cavalo (Luehea divaricata Mart.), uma espécie arbórea, heliófita e hermafrodita, muito utilizada na medicina popular. O estudo da composição bioquímica de sementes florestais é muito importante para a obtenção de informações sobre a espécie e para o delineamento de estratégias de conservação. O objetivo deste trabalho foi quantificar a variação genética para caracteres bioquímicos (teores de proteínas, carboidratos e amido) das sementes e determinar o ganho genético a partir da seleção de árvores provenientes de uma população natural de L. divaricata. A população de polinização livre está localizada na área de empréstimo da Fazenda de Ensino, Pesquisa e Extensão da Faculdade de Engenharia de Ilha Solteira (FEIS/UNESP), no município de Selvíria - MS. Foram coletadas aleatoriamente sementes de 12 árvores matrizes para análises de composição química, visando à determinação de caracteres bioquímicos. A partir destes, foram estimados os parâmetros genéticos e estatísticos, e para isto, foi utilizado o delineamento de blocos ao acaso, com 12 tratamentos (árvores matrizes), quatro repetições e uma planta por parcela. A população apresentou variação genética para os caracteres bioquímicos. Os maiores valores de herdabilidade média entre as progênies foram encontrados para os caracteres bioquímicos prolamina (0,98) e albumina (0,95), portanto serão as características que responderam mais facilmente à seleção. Portanto, a presente população de L. divaricata apresentou ampla base genética, sendo promissora a sua utilização em programas de conservação e melhoramento genético

Bioprocess and biotecnology: effect of xylanase from Aspergillus niger and Aspergillus flavus on pulp biobleaching and enzyme production using agroindustrial residues as substract

This study compares two xylanases produced by filamentous fungi such as A. niger and A. flavus using agroindustrial residues as substract and evaluated the effect of these enzymes on cellulose pulp biobleaching process. Wheat bran was the best carbon source for xylanase production by A. niger and A. flavus. The production of xylanase was 18 and 21% higher on wheat bran when we compare the xylanase production with xylan. At 50°C, the xylanase of A. niger retained over 85% activity with 2 h of incubation, and A. flavus had a half-life of more than 75 minutes. At 55°C, the xylanase produced by A. niger showed more stable than from A. flavus showing a half-life of more than 45 minutes. The xylanase activity of A. niger and A. flavus were somehow protected in the presence of glycerol 5% when compared to the control (without additives). On the biobleaching assay it was observed that the xylanase from A. flavus was more effective in comparison to A. niger. The kappa efficiency corresponded to 36.32 and 25.93, respectively. That is important to emphasize that the cellulase activity was either analyzed and significant levels were not detected, which explain why the viscosity was not significantly modified.This work was supported by grants from Conselho de Desenvolvimento Científico e Tecnológico (CNPq). This work was part of Master Dissertation of NCAG (Laboratório de Bioquímica / CCBS, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS, Brasil). The authors gratefully for the support from the USP/Ribeirão Preto – SP, Brazil.This work was supported by grants from Conselho de Desenvolvimento Científico e Tecnológico (CNPq). This work was part of Master Dissertation of NCAG (Laboratório de Bioquímica / CCBS, Universidade Federal de Mato Grosso do Sul, Campo Grande, MS, Brasil). The authors gratefully for the support from the USP/Ribeirão Preto – SP, Brazil

Biochemical characterization, thermal stability, and partial sequence of a novel exo-polygalacturonase from the thermophilic fungus Rhizomucor pusillus a13.36 obtained by submerged cultivation

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)This work reports the production of an exo-polygalacturonase (exo-PG) by Rhizomucor pusillus A13.36 in submerged cultivation (SmC) in a shaker at 45 degrees C for 96 h. A single pectinase was found and purified in order to analyze its thermal stability, by salt precipitation and hydrophobic interaction chromatography. The pectinase has an estimated Mw of approximately 43.5-47 kDa and optimum pH of 4.0 but is stable in pH ranging from 3.5 to 9.5 and has an optimum temperature of 61 degrees C. It presents thermal stability between 30 and 60 degrees C, has 70% activation in the presence of Ca2+, and was tested using citrus pectin with a degree of methyl esterification (DE) of 26% E-a(d) for irreversible denaturation was 125.5 kJ/mol with positive variations of entropy and enthalpy for that and Delta G((d)) values were around 50 kJ/mol. The hydrolysis of polygalacturonate was analyzed by capillary electrophoresis which displayed a pattern of sequential hydrolysis (exo). The partial identification of the primary sequence was done by MS MALDI-TOF and a comparison with data banks showed the highest identity of the sequenced fragments of exo-PG from R. pusillus with an exo-pectinase from Aspergillus fumigatus. Pectin hydrolysis showed a sigmoidal curve for the Michaelis-Menten plot.This work reports the production of an exo-polygalacturonase (exo-PG) by Rhizomucor pusillus A13.36 in submerged cultivation (SmC) in a shaker at 45 degrees C for 96 h. A single pectinase was found and purified in order to analyze its thermal stability, b2016110CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORCNQP - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)SEM INFORMAÇÃOSEM INFORMAÇÃO11/23991-710/12624-0This work was funded by CAPES, CNPq, and FAPESP (11/23991-7 and 10/12624-0).The authors thank the National Laboratory of Science and Technology of Bioethanol (CTBE), in Campinas, SP (Brazil), for mass spectrometry analysis and also Ms. Fatima Zapata fro