Thermostability of xylanolytic enzymes produced by Lentinula edodes UFV70

Abstract

Xylanolytic enzymes produced by Lentinula edodes UFV70, cultivated in eucalyptus sawdust/rice bran medium, were stable at 50, 60 and 65°C for 21 hours, losing only 15-25% activity. Fungus incubation at 50°C for 12 hours and at 65°C for 24 hours increased the amount of xylose produced.

Keywords: Lentinula edodes; thermostability; xylanase; xylose.

Figure 1

Thermostability of xylanolytic enzymes in crude extract at 50 °C (•), 60 °C (■), and 65 °C (A), for up to 21 hours. The activity was measured after incubating 300 uL of the crude enzymatic extract with 100 μL of 1% “Birchwood” xylan for 40 minutes at 40 °C. 100% represents the activity of enzymes without pre-incubation.

Figure 2

Xylose concentrations in the extracts from thermal treatments. During each week, samples were collected and submitted to high temperatures for 12 and 24 hours. Xylose was quantified by HPLC analysis, using an HPX 787 column and 50 mM sulfuric acid as the mobile phase. — - Control (xylose concentration in samples that were collected before thermal treatment); • - 12 hours at 65 °C; ♦ -24 hours at 65 °C; A - 12 hours at 50 °C; ■ - 24 hours at 50 °C.