Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile (USACH), Alameda 3363, Estación Central, 9170022, Santiago, Chile.
Published: January 2014
AI Article Synopsis
Article Abstract
Despite their potential biotechnological applications, cold-active xylanolytic enzymes have been poorly studied. In this work, 38 fungi isolated from marine sponges collected in King George Island, Antarctica, were screened as new sources of cold-active xylanases. All of them showed xylanase activity at 15 and 23 °C in semiquantitative plate assays. One of these isolates, Cladosporium sp., showed the highest activity and was characterized in detail. Cladosporium sp. showed higher xylanolytic activity when grown on beechwood or birchwood xylan and wheat bran, but wheat straw and oat bran were not so good inducers of this activity. The optimal pH for xylanase activity was 6.0, although pH stability was slightly wider (pH 5-7). On the other hand, Cladosporium sp. showed high xylanase activity at low temperatures and very low thermal stability. Interestingly, thermal stability was even lower after culture media were removed and replaced by buffer, suggesting that low molecular component(s) of the culture media could be important in the stabilization of cold-active xylanase activity. To the best of our knowledge, this study is the first report on extracellular xylanase production by fungi associated with Antarctic marine sponges.
The genus , known for its melanized, yeast-like appearance, includes a diverse group of fungi with significant implications across various fields. An isolate representing a novel species was identified within this genus from a ginger tuber from India, based on morphological characteristics and molecular phylogenetic analysis. Phylogenetic analysis of the D1/D2 domain of the 26S LSU rRNA gene, SSU rRNA gene and the internal transcribed spacer (ITS) region confirmed this strain as a new species.
Unlabelled: Wheat ( L.), a vital cereal crop, provides over 20% of the total calories and protein in the human diet. However, , the pathogen responsible for Fusarium head blight (FHB), poses a significant threat to wheat production by contaminating grains with harmful mycotoxins.
Background: Bacillus subtilis is widely used for industrial enzyme production due to its capacity to efficiently secrete proteins. However, secretion efficiency of enzymes varies widely, and optimizing secretion is crucial to make production commercially viable. Previously, we have shown that overexpression of the xylanase XynA lowers expression of Clp protein chaperones, and that inactivation of CtsR, which regulates and represses clp transcription, increases the production of XynA.
Rumen fluid (RF) is the greatest source of uncontrolled inter-assay variations in in vitro digestibility tests. This study aimed to investigate the effect of donor cow (DC) individual variability, time relative to feeding, and weekly sampling intervals on RF microbiota structure and metabolism, and on its degradative capacity expressed as enzymatic activity (EA). RF was collected using an esophageal probe from 4 Holstein hay-fed DCs before feeding, and 4 and 8 h post-feeding, over 3 days with one-week intervals, for a total of 3 weeks.
