Production of Xylanolytic Enzyme Complex fromAspergillus flavususing Agricultural Wastes

Abstract

Five types of agricultural wastes were used for the production of xylanolytic enzyme by Aspergillus flavus K-03. All wastes materials supported high levels of xylanase and β-xylosidase production. A high level of proteolytic activity was observed in barley and rice bran cultures, while only a weak proteolytic activity was detected in corn cob, barley and rice straw cultures. Maximum production of xylanase was achieved in basal liquid medium containing rice barn as carbon source for 5 days of culture at pH 6.5 and 25℃. The xylanolytic enzyme of A. flavus K-03 showed low thermostability. The times required for 50% reduction of the initial enzyme activity were 90 min at 40℃, 13 min at 50℃, and 3 min at 60℃. Xylanolytic activity showed the highest level at pH 5.5~10.5 and more than 70% of the original activity was retained at pH 6.5 and 7.0. The higher stability of xylanolytic enzymes in the broad range of alkaline pH is useful for utilization of the enzymes in industrial process requiring in alkaline conditions. Moreover, the highest production of xylanolytic enzyme was obtained when 0.5% of rice bran was supplied in basal liquid medium. SDS-PAGE analysis revealed a single xylanase band of approximately 28.5 kDa from the culture filtrates.

Characterization of a novel xylanase from Aspergillus flavus with the unique properties in production of xylooligosaccharides

“…will be maximal between 45 and 60 °C. Compared to the xylanases from all of A. flavus strains and most other reported Aspergillus sp., AfXynB exhibited a little higher optimum temperature for its maximal enzyme activity . AfXynB was found to be stable up to 50 °C (Figure d), which is similar to the thermostability of those xylanases produced by mesophilic fungi .…”

“…Although a great number of xylanases have been studied in different Aspergillus strains [21][22][23], few reports are available on the properties of the xylanases from A. flavus. Till date, only four xylanases from A. flavus had been purified and characterized, which had respective molecular mass at 14.0, 20.2, 28.5, and 35.0 kDa [24][25][26][27]. In the present study, a novel xylanase (AfXynB) from A. flavus with a different molecular mass of 32.2 kDa was purified and characterized.…”

“…Till date, only four xylanases from A . flavus had been purified and characterized, which had respective molecular mass at 14.0, 20.2, 28.5, and 35.0 kDa . In the present study, a novel xylanase (AfXynB) from A .…”

A comparative genomics study of 23 Aspergillus species from section Flavi

“…Carbohydrate-Active enZymes (CAZymes) are essential for what carbon sources a species can degrade and utilize. Within section Flavi the CAZymes/carbon utilization is mainly described for A. oryzae 1,2,40 and to a lesser extent for A. flavus [41][42][43][44][45] and A. sojae 46,47 , while only incidental studies have been performed with other species of this group [48][49][50][51][52][53][54] , often describing production or characterization of a certain CAZyme activity or protein, respectively.…”