Identification of markers at various stages of batch fermentation and improved production of xylanase using Aspergillus niger (KP874102.1).

Improved xylanase production was carried out through optimization of environmental stresses during spore preservation, seed cultivation and batch fermentation and identifies the markers at various stages. The maximum spore size (radius 6.5 µm) of Aspergillus niger was noticed after 28 days of spore preservation. During seed cultivation, the hypha formed alongside of germination tube (length 196.8 µm) was noticed only at pH-7 after 18 h of incubation at 28 °C. Therefore, pH-7 and 28 °C were considered as optimum during seed cultivation. In this stage, the final pH of the medium was found to be 6.2 which can be used as marker for completion of seed culture. The production media was optimized through Taguchi methodology. The maximum xylanase production was found to be 1575.93 U. The optimum concentration for media components was found to be xylan from beechwood of 3 g/l, potassium nitrate of 10 g/l, magnesium sulphate of 5 g/l, di-potassium hydrogen phosphate of 50 mM, calcium carbonate of 2 g/l, 1000× of trace element (1 ml) and sodium chloride of 5 g/l. It is evident that improved production of xylanase can be possible through optimization of environmental stresses during spore preservation, seed cultivation and batch fermentation and can be intensified through identification of markers at various stages of fermentation process.

Isolation, screening and characterization of a novel extracellular xylanase from Aspergillus niger (KP874102.1) and its application in orange peel hydrolysis.

In the present work, a potent xylanase producing fungal strain Aspergillus niger (KP874102.1) was isolated through cultural and morphological observations from soil sample of Baramura forest, Tripura west, India. 28S rDNA technique was applied for genomic identification of this fungal strain. The isolated strain was found to be phylogenetically closely related to Aspergillus niger. Kinetic constants such as Km and Vmax for extracellular xylanase were determined using various substrate such as beech wood xylan, oat spelt xylan and CM cellulose through Lineweaver-Burk plot. Km, Vmax and Kcat for beech wood xylan are found to be 2.89mg/ml, 2442U and 426178Umlmg-1 respectively. Crude enzyme did not show also CM cellulose activity. The relative efficiency of oat spelt xylan was found to be 0.819 with respect to beech wood xylan. After acid hydrolysis, enzyme was able to produce reducing sugar with 17.7, 35.5, 50.8 and 65% (w/w) from orange peel after 15, 30, 45 and 60min incubation with cellulase free xylanase and maximum reducing sugar formation rate was found to be 55.96µg/ml/min. Therefore, the Aspergillus niger (KP874102.1) is considered as a potential candidate for enzymatic hydrolysis of orange peel.

Classification, mode of action and production strategy of xylanase and its application for biofuel production from water hyacinth.

Xylanases are classified under glycoside hydrolase families which represent one of the largest groups of commercial enzymes. Depolymerizing xylan molecules into monomeric pentose units involves the synergistic action of mainly two key enzymes which are endo-ß-xylanase and ß-xylosidase. Xylanases are different with respect to their mode of action, substrate specificities, biochemical properties, 3D structure and are widely produced by a spectrum of bacteria and fungi. Currently, large scale production of xylanase can be produced through the application of genetic engineering tool which allow fast identification of novel xylanase genes and their genetic variations makes it an ideal enzymes. Due to depletion of fossil fuel, there is urgent need to find out environment friendly and sustainable energy sources. Therefore, utilisation of cheap lignocellulosic materials along with proper optimisation of process is most important for cost efficient ethanol production. Among, various types of lignocellulosic substances, water hyacinth, a noxious aquatic weed, has been found in many tropical. Therefore, the technological development for biofuel production from water hyacinth is becoming commercially worthwhile. In this review, the classification and mode of action of xylanase including genetic regulation and strategy for robust xylanase production have been critically discussed from recent reports. In addition various strategies for cost effective biofuel production from water hyacinth including chimeric proteins design has also been critically evaluated.