Improvement of xylanase production by a parasexual cross between Aspergillus niger strains

Abstract

A diploid strain (D4) isolated via parasexual recombination between two

Selection of improved Beauveria bassiana (Bals.) Vuill. strains based on 2-deoxy-d-glucose resistance and physiological analysis

“…Dodge, it has been shown that some 2DG-resistant mutants increase the production of invertases and glucoamylases (Allen et al, 1989). Similarly, in Aspergillus niger van Tieghem, some 2DG resistant mutants improve the expression of enzymes such pectinases, xylanases, and frutofuranosidase (Loera et al, 1999;Loera and Córdova, 2003;Ashokkumar et al, 2004). This has been found also for Saccharomyces cerevisiae Meyen ex E.C.…”

Use of oval conidia as a tool to assess the genetic transfer among Colletotrichum sublineolum mutants

“…The parasexual cycle was originally reported in A. nidulans but can be observed in many Ascomycetes, Deuteromycetes and Basidiomycetes. The parasexual cycle has also been useful in genetic improvement of fungal strains (Loera and Córdova, 2003) However, in various fungal species, the processes of parasexual recombination take place differently from the pattern described originally by Pontecorvo et al (1953) (Debets, 1998). In some species, the diploid phase is considered transient, usually not identified, and the recombinants can be obtained directly from the heterokaryon.…”

Effects of Pleurotus sapidus (Schulzer) Sacc. treatment on nutrient composition and ruminal fermentability of barley straw, barley rootless, and a mixture of the two

“…The enzyme was deactivated by immediately placing the tubes into a boiling water bath for 5 min after being withdrawn from the incubator. Samples were analyzed for reducing sugar after the tubes were cooled on ice for 10 min; absorbance was measured at 540 nm against a blank prepared in the same way but with a sample of 0.2 mL of 50 mM citrate-Na citrate buffer pH 5.3 (Loera and Córdova, 2003). Laccase activity was determined by first mixing 0.1 mL supernatant with 0.8 mL citrate buffer (50 mM, pH 5.3) in a glass tube; tubes were then placed in a water bath set at 40 ºC and 0.1 mL of substrate 0.1 M 2,2'-azino-bis.acid(3-ethylbenzothiazoline-6-sulfonic acid) was added.…”