Production of thermostable glucoamylase by newly isolated Aspergillus flavus A 1.1 and Thermomyces lanuginosus A 13.37

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

Production and characterization of glucoamylase from fungus Aspergillus awamori expressed in yeast Saccharomyces cerevisiae using different carbon sources

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

Localization and partial characterization of thermostable glucoamylase produced by newly isolated Thermomyces lanuginosus TO3 in submerged fermentation

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

Influence of Different Substrates on the Production of a Mutant Thermostable Glucoamylase in Submerged Fermentation

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

Partitioning of the glucoamylase activity at the cell surfaces in cultures of Saccharomyces

Glucoamylases have been used with alpha-amylases for the industrial conversion of starch into glucose. However, little is known about the properties of this glycosylated protein retained in the cell wall of Saccharomyces as well as its role in the saccharification and fermentation of amylaceous substrates, notably in high cell density processes. In most of the strains assayed, decreases in biomass formation were followed by increases in glucoamylase secretion (expressed as U/mg(biomass) in 1 ml of culture) when glucose was exchanged for starch as carbon source or the growth temperature was raised from 30 to 35 degrees C. Despite the losses in viability, significant increases in the activity of the wall fraction occurred when cultures of thermotolerant yeasts propagated at 30 degrees C or washed cells resuspended in buffer solution were heated to 60 degrees C for 60-80 min prior to amylolytic assays. Thus, intact cells of thermotolerant yeasts can be used as colloidal biocatalysts in starch degradation processes. (C) 2005 Published by Elsevier Ltd.

Improvement of Aspergillus niger glucoamylase thermostability by directed evolution

Directed evolution was used to improve the thermostability of Aspergillus niger glucoamylase (GA) expressed in Saccharomyces cerevisiae. A starch-plate assay developed to screen GA mutants for thermostability gave results consistent with those of irreversible thermoinactivation kinetic analysis. Several thermostable multiply-mutated GAs were isolated and characterized by DNA sequencing and kinetic analysis. Three new GA mutations, T62A, T290A and H391Y, have been identified that encode GAs that are more thermostable than wild-type GA, and that improve thermostability cumulatively. These individual mutations were combined with the previously constructed thermostable site-directed mutations D20C/A27C (forming a disulficle bond), S30P, and G137A to create a multiply-mutated GA designated THS8. THS8 GA is substantially more thermostable than wild-type GA at 8OoC, with a 5.1 kJ/mol increase in the free energy of therrnoinactivation, making it the most thermostable Aspergillus niger GA mutant characterized to date. THS8 GA and the singly-mutated GAs have specific activities and catalytic efficiencies (k(cat)/K-m) similar to those of wild-type GA.

Development of rapidly fermenting strains of saccharomyces-diastaticus for direct conversion of starch and dextrins to ethanol

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

Evidence of thermostable amylolytic activity from Rhizopus microsporus var. rhizopodiformis using wheat bran and corncob as alternative carbon source

Rhizopus microsporus var. rhizopodiformis produced high levels of alpha-amylase and glucoamylase under solid state fermentation, with several agricultural residues, such as wheat bran, cassava flour, sugar cane bagasse, rice straw, corncob and crushed corncob as carbon sources. These materials were humidified with distilled water, tap water, or saline solutions-Segato Rizzatti (SR), Khanna or Vogel. The best substrate for amylase production was wheat bran with SR saline solution (1:2 v/v). Amylolytic activity was still improved (14.3%) with a mixture of wheat bran, corncob, starch and SR saline solution (1:1:0.3:4.6 w/w/w/v). The optimized culture conditions were initial pH 5, at 45 degrees C during 6 days and relative humidity around 76%. The crude extract exhibited temperature and pH optima around 65 degrees C and 4-5, respectively. Amylase activity was fully stable for 1 h at temperatures up to 75 degrees C, and at pH values between 2.5 and 7.5.

Enzyme use in kibble diets formulated with wheat bran for dogs: Effects on processing and digestibility

Recently, there is an interest in technologies that favour the use of coproducts for animal nutrition. The effect of adding two enzyme mixtures in diets for dogs formulated with wheat bran (WB) was evaluated. Two foods with similar compositions were formulated: negative control (NC; without WB) and test diet (25% of WB). The test diet was divided into four treatments: without enzyme (positive control), enzyme mixture 1 (ENZ1; added before extrusion β-glucanase, xylanase, cellulase, glucoamylase, phytase); enzyme mixture 2 (ENZ2; added before extrusion the ENZ1 more α-amylase); enzyme mixture 2 added after the extrusion (ENZ2ex). ENZ1 and ENZ2 were used to evaluate the enzyme effect on extruder pre-conditioner (processing additive) and ENZ2ex to evaluate the effect of enzyme supplementation for the animal. Digestibility was measured through total collection of faeces and urine. The experiment followed a randomized block design with five treatments (diets) and six dogs per diet, totalling 30 dogs (7.0 ± 1.2 years old and 11.0 ± 2.2 kg of body weight). Data were submitted to analysis of variance and means compared by Tukey's test and orthogonal contrasts (p < 0.05). Reducing sugars showed an important reduction after extrusion, suggesting the formation of carbohydrate complexes. The apparent total tract digestibility (ATTD) of dry matter, organic matter, crude protein, acid-hydrolysed fat and energy was higher in NC than in diets with WB (p < 0.001), without effects of enzyme additions. WB diets resulted in higher faecal production and concentration of short-chain fatty acids (SCFA) and reduced pH and ammonia concentration (p < 0.01), with no effect of enzyme addition. The enzyme addition did not result in improved digestibility of a diet high in non-starch polysaccharides; however, only ATTD was measured and nutrient fermentation in the large intestine may have interfered with the results obtained. WB modified fermentation product formation in the colon of dogs. © 2013 Blackwell Verlag GmbH.

Production and application of amylases of Rhizopus oryzae and Rhizopus microsporus var. oligosporus from industrial waste in acquisition of glucose

Amylases from Rhizopus oryzae and Rhizopus microsporus var. oligosporus were obtained using agro-industrial wastes as substrates in submerged batch cultures. The enzymatic complex was partially characterised for use in the production of glucose syrup. Type II wheat flour proved better than cassava bagasse as sole carbon source for amylase production. The optimum fermentation condition for both microorganisms was 96 hours at 30°C and the amylase thus produced was used for starch hydrolysis. The product of the enzymatic hydrolysis indicated that the enzyme obtained was glucoamylase, only glucose as final product was attained for both microorganisms. R. oligosporus was of greater interest than R. oryzae for amylase production, taking into account enzyme activity, cultivation time, thermal stability and pH range. Glucose syrup was produced using concentrated enzyme and 100 g L-1 starch in a 4 hours reaction at 50°C. The bioprocess studied can contribute to fungus glucoamylase production and application. © 2013 Institute of Chemistry, Slovak Academy of Sciences.

Produção e caracterização de glucoamilases termoestáveis de Aspergillus awamori obtidas por PCR mutagênico e expressas em Saccharomyces cerevisiae

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Isolamento de linhagens microbianas termofílicas amilolíticas, produção, caracterização e aplicação das amilases na hidrólise do amido de mandioca

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

Produção de alfa-amilase e glucoamilase termoestável pelo fungo termofílico Thermomyces lanuginosus TO-03 por fermentação submersa e em estado sólido e caracterização das enzimas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)