Production and characterisation of recombinant α-l-arabinofuranosidase for production of xylan hydrogels

Identification of a Classical Mutant in the Industrial HostAspergillus nigerby Systems Genetics: LaeA Is Required for Citric Acid Production and Regulates the Formation of Some Secondary Metabolites

“…Owing to its low production of proteases, the A. niger D15 mutant has been used in various studies of the production of heterologous proteins (Gordon et al 2002; Rose and van Zyl 2002 ; Record et al 2003 ; Benoit et al 2007 ; Chimphango et al 2012 ; Turbe-Doan et al 2013 ; Benghazi et al 2014 ; Piumi et al 2014 ; Zwane et al 2014 ). The D15 strain does not only contain a mutation in the protease regulator gene ( prtT ) ( Punt et al 2008 ) but also a mutation leading to a nonacidifying phenotype and, consequently, low levels of acid-induced proteases in the medium.…”

Modifying solubility of polymeric xylan extracted from Eucalyptus grandis and sugarcane bagasse by suitable side chain removing enzymes

“…The enzymes used were (1) ␣-larabinofuranosidase (EC 3.2.1.55) (AbfB) with a volumetric activity of 1.1 U/ml on p-nitrophenyl arabinofuranoside (p-NPA) (Sigma) (Chimphango, Rose, et al, 2012) produced from recombinant A. niger and (2) crude recombinant ␣-d-glucuronidases (EC 3.2.1.139) (Agu1B) supernatant, endo-␤-xylanase free produced from Saccharomyces cerevisiae (Anane, van Rensburg, & Görgens, 2013), at concentrations of 462 mg/L, respectively. The Agu1B was expressed from S. cerevisae in which Scheffersomyces stipitis CBS 6054 ␣-dglucuronidase was integrated into the S. cerevisiae agu1B genome that showed 100% homology with the published S. stipitis CBS 6054 gene sequence (La Grange, unpublished results).…”

“…Extractives and ash content were determined with the NREL-TP 510-42619 and NREL-TP 510-42622 methods, respectively . The monomeric sugar profile and lignin content of the lignocellulose feedstocks and extracted xylans were performed according to the NREL-TP-510-42618 method, as described previously (Chimphango, Rose, et al, 2012;Sluiter et al, 2010). The total neutral sugar content of the feedstocks and the extracted xylans were determined by HPLC (Aminex HPX-87 P column, equipped with an evaporative light scattering detector (ELS), at a flow rate of 0.4 ml/min and distilled water as the eluent (18 M )), and subsequently quantified from standard plots of glucose, arabinose, xylose, rhamnose, mannose and galactose.…”

“…Precipitation of xylan hemicelluloses into hydrogels, with varying morphological properties, can be achieved by physical, chemical and enzymatic methods (Chimphango, Rose, van Zyl, & Görgens, 2012;Haimer et al, 2010;Ren & Sun, 2010;Tanodekaew, Channasanon, & Uppanan, 2006). Hydrogels were obtained by selective removal of arabinose from extracted arabinoglucuronoxylans using the ␣-l-arabinofuranosidase enzyme from family GH54 (AbfB), produced by expression in Aspergillus niger (Chimphango et al, 2012a).…”

Cationization of Eucalyptus grandis 4-O-methyl glucuronoxylan for application as a wet-end additive in a papermaking process

“…The functional properties of the hemicelluloses are enhanced by the modification of physical and/or chemical properties such as degree of substitution (DS), surface charge, and solubility (Chimphango et al 2012c). For example, the less branched hemicelluloses, in the form of hydrogels, adsorb onto cellulose (Kabel et al 2007;Köhnke et al 2009).…”