Feruloyl esterase (FAE-1) sourced from a termite hindgut and GH10 xylanases synergy improves degradation of arabinoxylan

Cereal feedstocks have high arabinoxylan content as their main hemicellulose, which is linked to lignin by hydroxycinnamic acids such as ferulic acid. The ferulic acid is linked to arabinoxylan by ester bonds, and generally, the high substitution of ferulic acid leads to a loss of activity of xylanases targeting the arabinoxylan. In the current study, a feruloyl esterase (FAE-1) from a termite hindgut bacteria was functionally characterised and used in synergy with xylanases during xylan hydrolysis. The FAE-1 displayed temperature and pH optima of 60 ℃ and 7.0, respectively. FAE-1 did not release reducing sugars from beechwood xylan (BWX), wheat arabinoxylan (WAX) and oat spelt xylan (OX), however, displayed high activity of 164.74 U/mg protein on p-nitrophenyl-acetate (pNPA). In contrast, the GH10 xylanases; Xyn10 and XT6, and a GH11 xylanase, Xyn2A, showed more than two-fold increased activity on xylan substrates with low sidechain substitutions; BWX and OX, compared to the highly branched substrate, WAX. Interestingly, the FAE-1 and GH10 xylanases (Xyn10D and XT6) displayed a degree of synergy (DS) that was higher than 1 in all enzyme loading combinations during WAX hydrolysis. The 75%XT6:25%FAE-1 synergistic enzyme combination increased the release of reducing sugars by 1.34-fold from WAX compared to the control, while 25%Xyn10D:75%FAE-1 synergistic combination released about 2.1-fold of reducing sugars from WAX compared to controls. These findings suggest that FAE-1 can be used in concert with xylanases, particularly those from GH10, to efficiently degrade arabinoxylans contained in cereal feedstocks for various industrial settings such as in animal feeds and baking.

Oviposition and Development of Tribolium Castaneum Herbst (Coleoptera: Tenebrionidae) on Different Types of Flour

The commercial availability of low-gluten or gluten-free flours has been increasing due to consumer demands, which raises new challenges for the management of stored product insects since little is known about the susceptibility of these flours to infestation. Here we measured oviposition and development of Tribolium castaneum, the red flour beetle, a major pest of wheat and rice mills, on 18 different commercially available flours (almond, amaranth, barley, buckwheat, cassava, coconut, corn, garbanzo, millet, oat, potato, quinoa, rice, rye, sorghum, spelt, teff, and wheat) to assess the level of risk. The average number of eggs laid was highest for teff flour, with wheat, rice, buckwheat, sorghum, barley, rye, and spelt flour also having high oviposition. The lowest oviposition was for potato, quinoa, amaranth and cassava. Holding the eggs laid in these flours and evaluating the ability to develop to the adult stage demonstrated that the average number of adult progeny was highest for teff and wheat, followed by buckwheat, rye, oat, spelt, and millet. In an experiment where single eggs were placed directly in flour, the highest percentage development was in barley, buckwheat, sorghum, spelt, teff, and wheat. Time for 50% of single eggs to develop to adults was quickest for sorghum, spelt, teff, and wheat, while sorghum, buckwheat, corn, spelt, and barley had the quickest development of 90% of eggs to reach adults. There was substantial variation among the different flours which indicates variation in risk of insect infestation. As consumer interest in these flours continues to grow and these alternative flours become more prevalent in food facilities, understanding what diets insects successfully infest is critical to developing management tools.

Using Lignosellulose Waste as a Xylanase Production Media of Mold Isolated from Rice Straw of Coastal-field

Hemicellulose is one of lignocellulose waste component, so that xylanase is one of importance enzyme of lignocellulose waste biodegradation. Molds as main decomposer lignosellulose waste has enzyme activities higher than yeast and bacteria. The aim of the research is to find mold that have xylanolitic activity using lignocellulose waste as media production. The research consist of isolations and screening mols from coastal-field of watu Ulo Jember, xylanase production using lignocellulose waste and idntification of mold which has the highes xylanase activity. A total of 66 molds isolated from rice straw in coastal-field of Watu Ulo Jember. There were screened for their xylanase activity. In semiquantitatively screen on Oat Spelt Xylan plate, the result showed that 62 have xilanolytic activities. Based on clearing zone production, isolates ESW A1 (3.2), ESW A5 (3.1), ESW C 16 (3.26), ESW D4 (3.0) and ESW D15 (3.21) have xilanase activity index higher than others. Furthermore, quantitative analysis using wheat bran, rice straw and baggase in basic salt Mandel’s modification media showed that xylanase activity of isolate ESW D4 was higher on rice straw 3% as substrate production with activity 2.66 U/mL. Isolate ESW D4 identified as Aspergillus foetidus so that called as Aspergillus foetidus ESW D4. Keywords: rice straw, coastal-field, Aspergillus foetidus ESW-D

Adsorption of cationized xylans onto polyethylene terephthalate fabrics for antimicrobial medical textiles

The main aim of this research was development of thin functional xylan layers on polyethylene terephthalate (PET) fabric surfaces. Xylans, derived from hard wood and oat spelt, were modified chemically in order to introduce cationic functional groups. Cationization of xylans was proved by elemental analysis, total bound nitrogen determination, and Raman techniques, as well as by polyelectrolyte titrations. The antimicrobial activity of xylans was investigated by the determination of Minimal Inhibitory Concentration against bacteria S. aureus and E. coli, and fungi C. albicans. Xylan solutions were then applied onto PET fabric using the spray coating technique. Charging behavior of the treated PET fabric samples was evaluated by potentiometric titration supported by X-ray electron spectroscopy. Hydrophilicity was examined by the water contact angle determination. The morphology of coated fabrics was analyzed using Scanning Electron Microscopy. The results of microbial testing showed that PET fabrics functionalized by cationic xylans act antimicrobially against S. aureus and E. coli. The presented work suggests that cationized xylans, originally derived from hard wood and/or oat spelt, could be applied successfully as a coating material for PET fabrics in order to introduce hydrophilicity and antimicrobial properties.

Xyn10A, a Thermostable Endoxylanase from Acidothermus cellulolyticus 11B

ABSTRACT We cloned and purified the major family 10 xylanase (Xyn10A) from Acidothermus cellulolyticus 11B. Xyn10A was active on oat spelt and birchwood xylans between 60°C and 100°C and between pH 4 and pH 8. The optimal activity was at 90°C and pH 6; specific activity and Km for oat spelt xylan were 350 μmol xylose produced min−1 mg of protein−1 and 0.53 mg ml−1, respectively. Based on xylan cleavage patterns, Xyn10A is an endoxylanase, and its half-life at 90°C was approximately 1.5 h in the presence of xylan.

Functional characterisation of a recombinant xylanase fromPichia pastorisand effect of the enzyme on nutrient digestibility in weaned pigs

Thexyn2gene of a filamentous mesophilic fungus,Trichoderma reesei, coding xylanase 2 (Xyn2) was previously expressed inPichia pastoris. In the present study, the recombinant Xyn2 was prepared from a 15 litre fermenter, and subsequently characterised. It has been confirmed to have a molecular mass of 21 kDa, an optimal pH of 6·0 and an optimal temperature of 60°C. When tested using oat-spelt xylan, it showed aKmand catalytic rate constant (kcat) of 1·1 mg/ml and 512·4/s, respectively. Analysis of the products from oat-spelt xylan degradation confirmed that the enzyme was an endoxylanase with xylotriose and xylobiose as the main degradation products. The unprocessed Xyn2 was supplemented to a xylan-containing diet to determine its influences on performance and nutrient digestibilities by weaned pigs. Results showed that the average body-weight gain increased 16·9 % when piglets received Xyn2 at a concentration of 500 U/kg diet. There also was a positive (0·05 < P < 0·10) effect on the digestibility values of crude protein, ash, Ca and acid-detergent fibre with Xyn2 supplementation. The potential benefits of Xyn2 in the nutrition of weaned pigs should make it an alternative applicant for industrial xylanase production.