Dataset Information

Purification, characterization, gene cloning and expression of GH-10 xylanase (Penicillium citrinum isolate HZN13).

ABSTRACT: An extracellular thermostable xylanase (Xyl-IIb) produced by Penicillium citrinum isolate HZN13 was purified to homogeneity using DEAE-Sepharose, Sephadex G-100 and Bio-Gel P-60 chromatography with specific activity of 6272.7 U/mg and 19.6-fold purification. The purification revealed the occurrence of multiple forms of xylanases (Xyl-I, Xyl-IIa, Xyl-IIb and Xyl-III). The molecular mass of highly purified Xyl-IIb was ~31 kDa with SDS-PAGE. The enzyme was cellulase-free, thermostable (55-75 °C) and acidophilic (3.5-5.0). It was activated by Ca2+, Ba2+, DTT and ?-mercaptoethanol, whereas inhibited by Hg2+, Pb2+, Ni2+ and p-CMB. Purified Xyl-IIb exhibited highest specificity toward birchwood and oat spelts xylan. Kinetics of Xyl-IIb revealed a K m of 10 mg/ml and 16.7 mg/ml and V max of 9523g and 15,873 U/mg with birchwood and oat spelts xylan, respectively, indicating high affinity toward birchwood xylan. The xylanase (Xyl-IIb) belongs to glycosyl hydrolase (GH) family 10 based on conserved regions. Xylanase-encoding gene (xynB) consists of 1501 bp with an open reading frame of 264 bp which was predicted to encode a protein having 87 amino acids and shared homology with endo-1,4-beta-xylanase (xynB) gene from Penicillium citrinum. Cloned xynB gene was expressed in E. coli BL21 (DE3) with xylanase activity (80 U/mg) and confirmed to be GH-10 Xyl-IIa based on molecular mass (~40 kDa). These properties of xylanase make it promising for their applications in biofuel industries.

SUBMITTER: Bagewadi ZK

PROVIDER: S-EPMC4987633 | biostudies-literature | 2016 Dec

REPOSITORIES: biostudies-literature

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Purification, characterization, gene cloning and expression of GH-10 xylanase (Penicillium citrinum isolate HZN13).

Bagewadi Zabin K ZK Mulla Sikandar I SI Ninnekar Harichandra Z HZ

3 Biotech 20160813 2

An extracellular thermostable xylanase (Xyl-IIb) produced by Penicillium citrinum isolate HZN13 was purified to homogeneity using DEAE-Sepharose, Sephadex G-100 and Bio-Gel P-60 chromatography with specific activity of 6272.7 U/mg and 19.6-fold purification. The purification revealed the occurrence of multiple forms of xylanases (Xyl-I, Xyl-IIa, Xyl-IIb and Xyl-III). The molecular mass of highly purified Xyl-IIb was ~31 kDa with SDS-PAGE. The enzyme was cellulase-free, thermostable (55-75 °C) an ...[more]

PMID: 28330241

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Project description:Background?-Glucosidases are components of the cellulase system, a family of enzymes that hydrolyze the ?-1,4 linkages of cellulose. These proteins have been extensively studied due to the possibility of their use in various biotechnological processes. They have different affinities for substrates (depending on their source) and their activities can be used for saccharification of different types of biomass. In this context, the properties and the synergistic capacity of ?-glucosidases from different organisms, to supplement the available commercial cellulase cocktails, need a comprehensive evaluation.ResultsTwo ?-glucosidases belonging to GH3 family were secreted by Penicillium citrinum UFV. Pc?Glu1 (241 kDa) and Pc?Glu2 (95 kDa) presented acidic and thermo-tolerant characteristics. Pc?Glu1 showed Michaelis-Menten kinetics for all substrates tested with Km values ranging from 0.09?±?0.01 (laminarin) to 1.7?±?0.1 mM (cellobiose, C2) and kcat values ranging from 0.143?±?0.005 (laminarin) to 8.0?±?0.2 s-1 (laminaribiose, Lb). Pc?Glu2 showed substrate inhibition for 4-methylumbelliferyl-?-d-glucopyranoside (MU?Glu), p-nitrophenyl-?-d-glucopyranoside (pNP?Glu), cellodextrins (C3, C4, and C5), N-octil-?-d-glucopyranoside, and laminaribiose, with Km values ranging from 0.014?±?0.001 (MU?Glu) to 0.64?±?0.06 mM (C2) and kcat values ranging from 0.49?±?0.01 (gentiobiose) to 1.5?±?0.2 s-1 (C4). Inhibition constants (Ki) for Pc?Glu2 substrate inhibition ranged from 0.69?±?0.07 (MU?Glu) to 10?±?1 mM (Lb). Glucose and cellobiose are competitive inhibitors of Pc?Glu1 and Pc?Glu2 when pNP?Glu is used as a substrate. For Pc?Glu1 inhibition, Ki?=?1.89?±?0.08 mM (glucose) and Ki?=?3.8?±?0.1 mM (cellobiose); for Pc?Glu2, Ki?=?0.83?±?0.05 mM (glucose) and Ki?=?0.95?±?0.07 mM (cellobiose). The enzymes were tested for saccharification of different biomasses, individually or supplementing a Trichoderma reesei commercial cellulose preparation. Pc?Glu2 was able to hydrolyze banana pseudostem and coconut fiber with the same efficiency as the T. reesei cocktail, showing significant synergistic properties with T. reesei enzymes in the hydrolysis of these alternative biomasses.ConclusionsThe ?-glucosidases from P. citrinum UFV1 present different enzymatic properties from each other and might have potential application in several biotechnological processes, such as hydrolysis of different types of biomass.

Project description:BACKGROUND: Endophytic fungi are known plant symbionts. They produce a variety of beneficial metabolites for plant growth and survival, as well as defend their hosts from attack of certain pathogens. Coastal dunes are nutrient deficient and offer harsh, saline environment for the existing flora and fauna. Endophytic fungi may play an important role in plant survival by enhancing nutrient uptake and producing growth-promoting metabolites such as gibberellins and auxins. We screened roots of Ixeris repenes (L.) A. Gray, a common dune plant, for the isolation of gibberellin secreting endophytic fungi. RESULTS: We isolated 15 endophytic fungi from the roots of Ixeris repenes and screened them for growth promoting secondary metabolites. The fungal isolate IR-3-3 gave maximum plant growth when applied to waito-c rice and Atriplex gemelinii seedlings. Analysis of the culture filtrate of IR-3-3 showed the presence of physiologically active gibberellins, GA1, GA3, GA4 and GA7 (1.95 ng/ml, 3.83 ng/ml, 6.03 ng/ml and 2.35 ng/ml, respectively) along with other physiologically inactive GA5, GA9, GA12, GA15, GA19, GA20 and, GA24. The plant growth promotion and gibberellin producing capacity of IR-3-3 was much higher than the wild type Gibberella fujikuroi, which was taken as control during present study. GA5, a precursor of bioactive GA3 was reported for the first time in fungi. The fungal isolate IR-3-3 was identified as a new strain of Penicillium citrinum (named as P. citrinum KACC43900) through phylogenetic analysis of 18S rDNA sequence. CONCLUSION: Isolation of new strain of Penicillium citrinum from the sand dune flora is interesting as information on the presence of Pencillium species in coastal sand dunes is limited. The plant growth promoting ability of this fungal strain may help in conservation and revegetation of the rapidly eroding sand dune flora. Penicillium citrinum is already known for producing mycotoxin citrinin and cellulose digesting enzymes like cellulase and endoglucanase, as well as xylulase. Gibberellins producing ability of this fungus and the discovery about the presence of GA5 will open new aspects of research and investigations.

Dataset Information

Purification, characterization, gene cloning and expression of GH-10 xylanase (Penicillium citrinum isolate HZN13).

Publications

Purification, characterization, gene cloning and expression of GH-10 xylanase (Penicillium citrinum isolate HZN13).

Similar Datasets

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