Xylooligosaccharides (XOS) from lignocellulosic biomass (LCB) have found widespread applications in food, feed, nutraceuticals and pharamecutical industries. Enzymatic degradation of LCB for generation of XOS have gained impetus in recent times In the present investigation an extracellular thermo-alkali stable xylanase from Aspergillus oryzae LC1 was purified by using PEG 8000/MgSO4 aqueous two-phase system and was capable of hydrolysing various agricultural residues into XOS system. Highest activity was observed using 11.3% (w/w) PEG 8000 and 22.5% (w/w) sulphate salt with maximum purification factor (13-fold), highest yield (86.8%) and partition coefficient (8.8%). The purification of the crude enzyme also resulted in decrement of β-xylosidase activity (29.8 U/mL to 0.6 U/mL). The molecular weight of enzyme was estimated ~35 kDa. The highest residual activity was obtained with birch wood xylan as substrate with Km and Vmax of 0.2 mg/mL and 172.2 μmol/min/mg respectively. The metal ions Fe2+, Ag2+, Mg2+, Mn+ and Co+ enhanced xylanase activity while EDTA, DMSO and SDS acted as inhibitor. The effect of Fe+2 was confirmed by the circular dichroism experiment. The partially purified enzyme was capable of generating XOS i.e. xylobiose (0.68 mg/g), xylotriose (2.47 mg/g) and xylotetraose (2.29 mg/g) by direct enzymatic hydrolysis of untreated sugarcane baggase, wheat straw and wheat bran respectively
aqueous two-phase system, Aspergillus oryzae, xylooligosaccharides
NCBI PubMed ID: 30223058Publication DOI: 10.1016/j.ijbiomac.2018.09.070Journal NLM ID: 7909578Publisher: Butterworth-Heinemann
Correspondence: Bhardwaj N <2014phdmb05@curaj.ac.in>; Kumar B <2015phdmb02@curaj.ac.in>; Agrawal K <2014phdmb03@curaj.ac.in>; Chaturvedi V
; Verma P ; Verma P
Institutions: Bioprocess and Bioenergy Laboratory, Department of Microbiology, Central University of Rajasthan, Kishangarh, India, SMW College, MG Kashi Vidyapeeth, Varanasi, India
Methods: gel filtration, SDS-PAGE, kinetics assays, TLC, electrophoresis, HPLC, enzymatic digestion, ion-exchange chromatography, extraction, CD, zymographic analysis, cell growth, dialysis, enzymatic assay, precipitation, spectrophotometry, centrifugation, dinitrosalicylic acid (DNS) method, Lowry method
Found