Production of Crude Xylanase from Thermoascus Aurantiacus CBMAI 756 Aiming the Baking Process

Abstract

In recent years, the baking industry has focused its attention on substituting several chemical compounds with enzymes. Enzymes that hydrolyze nonstarch polysaccharides, such as xylanase, lead to the improvement of rheological properties of dough, loaf specific volume, and crumb firmness. The purpose of this study was to find a better solid-state fermentation substrate to produce high levels of xylanase and low levels of protease and amylase, which are enzymes involved in bread quality, from Thermoascus aurantiacus CBMAI 756. Wheat bran, corncob, and corn straw were used as energy sources. The enzyme extract of corncob showed high xylanase activity (130 U/mL) and low amylase and protease activity (<1 and 15 U/mL, respectively). This enzyme profile may be more profitable for the baking industry, because it results in a slower degradation of gluten. Our results confirm this finding, because the enzyme obtained by fermentation in corncob resulted in a gluten with a higher specific volume than all the other substrates that were tested. The crude xylanase presented maximum activity at a pH of 5, and the optimum temperature was 75 °C. It was stable up to 70 °C for an hour and at a pH range from 4 to 10.

Role of N-linked glycosylation in the enzymatic properties of a thermophilic GH 10 xylanase from Aspergillus fumigatus expressed in Pichia pastoris

“…A few xylanases from thermophilic fungus Thermoascus aurantiacus CBMAI 756 (75°C), Xyn10B and Xyn10C from Chrysosporium lucknowense (80–85°C), and XYL10C from Bispora sp. MEY-1 (85°C) have higher temperature optima than Af-XYNA [ 36 – 37 ]. In addition, Af-XYNA was highly stable at 60°C, retaining >80% activity after 1 h incubation at 60°C without substrate, but lost activity rapidly when treated at 70°C ( Fig 4d ).…”

Thermophilic fungi as new sources for production of cellulases and xylanases with potential use in sugarcane bagasse saccharification

“…; Oliveira et al . ). For all these enzymes, one unit enzyme activity (U) was defined as the amount of enzyme required to release 1·0 μ mol of reducing sugar per minute, under assay conditions.…”

“…Cellulase activity on filter paper (FPase) was assayed as described by Ghose (1987). Controls were prepared by adding the enzyme after addition of the 3,5-dinitrosalicylic acid reagent (Alves-Prado et al 2010;Oliveira et al 2010). For all these enzymes, one unit enzyme activity (U) was defined as the amount of enzyme required to release 1Á0 lmol of reducing sugar per minute, under assay conditions.…”

Microbial biosynthesis of enzymes for food applications

“…An oxidase with high reactivity to maltose, lactose, cellobiose, and maltooligosaccharides composed of up to seven glucose units was obtained from the solid culture of wheat bran (Lin et al, 1993). The raw materials used in these experiments were wheat bran, corncob, and corn straw, producing an enzyme stable at high temperatures and extreme pH values (Oliveira et al, 2010). Thermoascus aurantiacus CBMAI 756, a thermophilic fungus, is able to produce xylanase (EC 3.2.1.8).…”