Hidrolitički potencijal β-ksilozidaze iz plijesni Talaromyces thermophilus i njezina primjena u kontinuiranoj proizvodnji ksiloze

We report here the enhanced hemicellulase production by a Talaromyces thermophilus strain in a fed-batch fermentation using 3.6-litre laboratory-controlled bioreactor. When grown on wheat bran, this fungus produces a wide spectrum of polysaccharide-hydrolysing enzymes, mainly endo-β-1,4-xylanase (27 U/mL), β-xylosidase (1.4 U/mL), α-L-arabinofuranosidase (1.05 U/mL) and β-D-mannosidase (0.78 U/mL). The β-xylosidase was purified and shown to hydrolyse xylobiose and short xylooligosaccharides, but it was inactive on xylan. It released xylose from xylooligosaccharides with a degree of polymerisation ranging from 2 to 5. Talaromyces thermophilus β-xylosidase activity was unaffected by high glucose or arabinose concentration (0.5 M) and retained 75 % of its original activity in the presence of 133 mM xylose. Chitosan-immobilised β-xylosidase was used in a continuous process of conversion of wheat bran hydrolysate to xylose in a packed bed reactor. Xylose production of 18.6 mg/g was reached after six hours in the bioreactor and was twofold higher than that produced by the free enzyme. The produced xylose was further converted into xylitol using the crude intracellular enzyme of Talaromyces thermophilus.U radu je opisana mogućnost povećanja proizvodnje hemicelulaze s pomoću soja plijesni Talaromyces thermophilus u šaržnom procesu s pritokom supstrata provedenom u laboratorijski kontroliranom bioreaktoru zapremnine 3,6 L. Na podlozi je od pšeničnih mekinja plijesan proizvela različite enzime što hidroliziraju polisaharide, kao što su: endo-β-1,4-ksilanaza (27 U/mL), β-ksilozidaza (1,4 U/mL), α-L-arabinofuranozidaza (1,05 U/mL) i β-D-manozidaza (0,78 U/mL). Pročišćena je β-ksilozidaza hidrolizirala ksilobiozu i kratkolančane ksilooligosaharide, dok u prisutnosti ksilana nije bila aktivna. Stupanj je polimerizacije ksiloze iz oligosaharida bio u rasponu od 2 do 5. Visoka koncentracija (0,5 M) glukoze ili arabinoze nije utjecala na aktivnost β-ksilozidaze iz plijesni Talaromyces thermophilus, koja je zadržala 75 % aktivnosti u prisutnosti 133 mM ksiloze. U kontinuiranoj proizvodnji ksiloze iz hidrolizata pšeničnih mekinja u reaktoru s nasutim slojem nosača korištena je β-ksilozidaza imobilizirana na kitozanu. Prinos ksiloze od 18,6 mg/g postignut je nakon 6 sati u bioreaktoru, što je dvostruko više od prinosa postignutog pomoću slobodnog enzima. Dobivena je ksiloza prevedena u ksilitol pomoću nepročišćenog intracelularnog enzima iz plijesni Talaromyces thermophilus

Purification and biochemical characterization of two novel extracellular keratinases with feather-degradation and hide-dehairing potential

peer reviewe

Nutritional Composition and Phytochemical, Antioxidative, and Antifungal Activities of Pergularia tomentosa L.

Crude extracts from a medicinal Tunisian plant, Pergularia tomentosa L., were the investigated natural material. Butanolic extract of roots analyzed with IR spectra revealed the presence of hydroxyl, alcoholic, and carboxylic groups and sugars units. Analysis of some secondary metabolites, total phenolic, flavonoids, flavonols, and procyanidins, was performed using different solvents following the increased gradient of polarity. Fruits and leaves contained the highest amounts of all these compounds. Antioxidant properties were evaluated by the determination of free radical scavenging activity and the reducing power of methanolic extracts. Fruits and leaf extracts were the most powerful antioxidants for the two-assay in vitro system. Stems and fruits extracts exhibit an antifungal activity against Fusarium oxysporum f. sp. lycopersici which could become an alternative to synthetic fungicide to control Solanum species fungal diseases

Hydrolytic Potential of Talaromyces thermophilus β-Xylosidase and Its Use for Continuous Xylose Production

We report here the enhanced hemicellulase production by a Talaromyces thermophilus strain in a fed-batch fermentation using 3.6-litre laboratory-controlled bioreactor. When grown on wheat bran, this fungus produces a wide spectrum of polysaccharide-hydrolysing enzymes, mainly endo-β-1,4-xylanase (27 U/mL), β-xylosidase (1.4 U/mL), α-L-arabinofuranosidase (1.05 U/mL) and β-D-mannosidase (0.78 U/mL). The β-xylosidase was purified and shown to hydrolyse xylobiose and short xylooligosaccharides, but it was inactive on xylan. It released xylose from xylooligosaccharides with a degree of polymerisation ranging from 2 to 5. Talaromyces thermophilus β-xylosidase activity was unaffected by high glucose or arabinose concentration (0.5 M) and retained 75 % of its original activity in the presence of 133 mM xylose. Chitosan-immobilised β-xylosidase was used in a continuous process of conversion of wheat bran hydrolysate to xylose in a packed bed reactor. Xylose production of 18.6 mg/g was reached after six hours in the bioreactor and was twofold higher than that produced by the free enzyme. The produced xylose was further converted into xylitol using the crude intracellular enzyme of Talaromyces thermophilus

Optimization, Purification, and Starch Stain Wash Application of Two New α-Amylases Extracted from Leaves and Stems of Pergularia tomentosa

A continuous research is attempted to fulfil the highest industrial demands of natural amylases presenting special properties. New α-amylases extracted from stems and leaves of Pergularia tomentosa, which is widespread and growing spontaneously in Tunisia, were studied by the means of their activities optimization and purification. Some similarities were recorded for the two identified enzymes: (i) the highest amylase activity showed a promoted thermal stability at 50°C; (ii) the starch substrate at 1% enhanced the enzyme activity; (iii) the two α-amylases seem to be calcium-independent; (iv) Zn2+, Cu2+, and Ag2+ were considered as important inhibitors of the enzyme activity. Following the increased gradient of elution on Mono Q-Sepharose column, an increase in the specific activity of 11.82-fold and 10.92-fold was recorded, respectively, for leaves and stems with the presence of different peaks on the purification profiles. Pergularia amylases activities were stable and compatible with the tested commercial detergents. The combination of plant amylase and detergent allowed us to enhance the wash performance with an increase of 35.24 and 42.56%, respectively, for stems and leaves amylases. Characterized amylases were reported to have a promoted potential for their implication notably in detergent industry as well as biotechnological sector

Evaluation of nutritional value, characteristics, functional properties of Cymodocea nodosa and its benefits on health diseases

Abstract Background Nutritional fact study has prime importance to make the species edible and commercially viable to the food consumers. This is the first report that indicates the chemical characterization, functional, antioxidant and antihypertensive properties of Cymodocea nodosa to evaluate its nutritional status. Methods Physico-chemical determination was determined by colorimetric and spectroscopic analysis. The functional and texture properties were evaluated since a desirable texture should be retained. Bioactive substances were determined by liquid chromatography-high resolution electrospray ionization mass spectrometry HPLC-DAD-ESI/MS2 analysis. Health benefit of this plant was highlighting by the antioxidant and antihypertensive potentials. Results Results showed that the seagrass powder was characterized by a high content of fibers (56.4%), the fatty acids profile was dominated by the oleic acid, which represents about 62.0% of the total fatty acids and the functional properties proved important values of swelling capacity (6.71 ± 0.2) and water holding capacity (12.26 ± 0.25), that were comparable to those of some foodstuffs. Finally, the physico-chemical analysis shows the wealth in phenolic compounds, that could be explained by the high antioxidant and antihypertensive ability which was concentration dependent. Conclusion The results from this study suggested that this marine plant could be utilized as a healthy food item for human consumption

Valorization of a plant β-amylase: Immobilization and dataset on the kinetic process

The data presented in this article are related to the research article titled “Immobilization nd topochemical mechanism of a new β-amylase extracted from Pergularia tomentosa” (Lahmar et al., 2017) [1]. This article documented information on the determination of the molecular weight of the β-amylase, the method of its immobilization and a comparison of the kinetic mechanism between the free and the immobilized forms by a mathematical method. Fresh Pergularia tomentosa was collected from Tunisia and a special method for β-amylase extraction was followed (Yotova et al., 2000) [2]. Public dissemination of this dataset will allow further analyses of the data

An efficient enzymatic-based process for the extraction of high-mechanical properties alfa fibres

International audienceAlfa fibres, which are generally extracted from the leaf of a plant belonging to the Poaceae family(Stipa tenacissima L), originating from the center of Tunisia, are mainly used for pulp and paper applica-tions. Their potential use as reinforcement in polymer composites requires the understanding of theirmicrostructure and mechanical properties and a proper control of fibre extraction and transformationprocesses. This work investigates the morphology of the alfa plant (leaves and fibres) through opticaland electron microscopy. The extraction process combining mechanical, chemical and enzymatic stagesand the reaction time of the enzymes have been optimised to achieve the highest mechanical propertiesof fibres. The effect of enzymatic treatments (laccase, pectinases and xylanases) on the morphological,chemical composition and mechanical properties of alfa fibres was investigated and the effectivenessof enzymatic treatments has been evaluated. The chemical compositions of alfa are correlated with itsmechanical properties. The result indicates that the tensile properties of isolated fibres were greatlyimproved when an optimised enzymatic-based process is used to separate the fibres from the leaves.Using pectinase and xylanase activities, results show really high mechanical properties, with an averagerigidity and strength up to, respectively, 66 GPa and 1300 MPa, which make alfa fibre promising reinforcements for load-bearing composite materials. This work also showed that enzymes offer an attractive andeco-friendly approach to efficiently extract high-performance plant fibres

Structural characterization and functional properties of antihypertensive Cymodocea nodosa sulfated polysaccharide

peer reviewedA sulfated polysaccharide was successfully isolated from Cymodocea nodosa (CNSP). This is the first report that indicates the chemical composition, structural characterization, functional and antihypertensive properties of this polysaccharide. The CNSP consisted mainly of sulfate (23.17%), total sugars (54.90%), galactose (44.89%), mannose (17.30%), arabinose (12.05%), xylose (9.18%), maltose (1.07%) and uronic acid (11.03%) with low water activity (0.49). CNSP had an XRD pattern that was typical for a semi-crystalline polymer with homogeneous structure. It also displayed an important anti-hypertensive activity (IC50 = 0.43 mg ml) with a dose-dependent manner using a synthetic substrate, N-hippuryl-His-Leu hydrate salt (HHL). Overall, the results indicate that CNSP have attractive chemical, functional and biological properties, with a preliminary structural may have a backbone of branched 6-O-sulfated (1 → 4) galactosidic linkages, which can be considered in the future as alternative additive in various foods, cosmetic and pharmaceutical preparations

Structural characterization and functional properties of antihypertensive Cymodocea nodosa sulfated polysaccharide

A sulfated polysaccharide was successfully isolated from Cymodocea nodosa (CNSP). This is the first report that indicates the chemical composition, structural characterization, functional and antihypertensive properties of this polysaccharide. The CNSP consisted mainly of sulfate (23.17%), total sugars (54.90%), galactose (44.89%), mannose (17.30%), arabinose (12.05%), xylose (9.18%), maltose (1.07%) and uronic acid (11.03%) with low water activity (0.49). CNSP had an XRD pattern that was typical for a semi-crystalline polymer with homogeneous structure. It also displayed an important anti-hypertensive activity (IC50 = 0.43 mg ml) with a dose-dependent manner using a synthetic substrate, N-hippuryl-His-Leu hydrate salt (HHL). Overall, the results indicate that CNSP have attractive chemical, functional and biological properties, with a preliminary structural may have a backbone of branched 6-O-sulfated (1 → 4) galactosidic linkages, which can be considered in the future as alternative additive in various foods, cosmetic and pharmaceutical preparations