@article { ISI:000280972500010, title = {Enzymatic hydrolysis and ethanol production using xyloglucanase and debaromyces hansenii from tamarind kernel powder: galactoxyloglucan predominant hemicellulose}, journal = {Journal of Biotechnology}, volume = {148}, number = {4}, year = {2010}, month = {AUG}, pages = {233-239}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

The hydrolysis and ethanol production from tamarind kernel powder (TKP), a rich source of galactoxyloglucan (GXG) was investigated for the first time using xyloglucanase and thermotolerant Debaromyces hansenii. The acid hydrolysis of TKP with 2N H(2)SO(4) at 120 degrees C for 30 min yielded an overall saccharification of 94\% based on the total available carbohydrate content and further fermentation at 40 degrees C with thermotolerant D hansenii produced an ethanol yield of 0.35 g/g. A maximum hydrolysis of 55 and 78\% for GXG was obtained in 48 h at 50 degrees C using Thermomonospora xyloglucanase (TXy) and accellerase (TM) 1000, respectively. The synergistic effect of beta-galactosidase and xyloglucanase was demonstrated by the exogenous addition of beta-galactosidase to TXy which improved the overall hydrolysis of GXG by 30\%. The rate of hydrolysis of GXG with TXy and accellerase was increased by 15-20\% in the presence of chemical surfactants (tween 80 and toluene) or protein additive (BSA). The fermentation of enzymatic hydrolysates of GXG by TXy and accellerase with free cells at 40 degrees C produced an ethanol yield of 0.39 and 0.41 g/g whereas with immobilized cells produced 0.45 and 0.43 g/g, respectively, with a theoretical conversion efficiencies of 78-88\%. The immobilized yeast cells were reused six times at 40 degrees C with 100\% fermentation efficiency. (C) 2010 Elsevier B.V. All rights reserved.

}, keywords = {Ethanol, Galactoxyloglucan, Hydrolysis, Tamarind kernel powder, Thermotolerant yeast, Xyloglucanase}, issn = {0168-1656}, doi = {10.1016/j.jbiotec.2010.06.004}, author = {Menon, Vishnu and Prakash, Gyan and Rao, Mala} } @article { ISI:000298390900013, title = {Biochemical characterization of a novel thermostable xyloglucanase from an alkalothermophilic thermomonospora sp.}, journal = {Extremophiles}, volume = {16}, number = {1}, year = {2012}, month = {JAN}, pages = {135-146}, publisher = {SPRINGER JAPAN KK}, address = {CHIYODA FIRST BLDG EAST, 3-8-1 NISHI-KANDA, CHIYODA-KU, TOKYO, 101-0065, JAPAN}, abstract = {

Xyloglucanase from an extracellular culture filtrate of alkalothermophilic Thermomonospora sp. was purified to homogeneity with a molecular weight of 144 kDa as determined by SDS-PAGE and exhibited specificity towards xyloglucan with apparent K (m) of 1.67 mg/ml. The enzyme was active at a broad range of pH (5-8) and temperatures (40-80A degrees C). The optimum pH and temperature were 7 and 70A degrees C, respectively. The enzyme retained 100\% activity at 50A degrees C for 60 h with half-lives of 14 h, 6 h and 7 min at 60, 70 and 80A degrees C, respectively. The kinetics of thermal denaturation revealed that the inactivation at 80A degrees C is due to unfolding of the enzyme as evidenced by the distinct red shift in the wavelength maximum of the fluorescence profile. Xyloglucanase activity was positively modulated in the presence of Zn2+, K+, cysteine, beta-mercaptoethanol and polyols. Thermostability was enhanced in the presence of additives (polyols and glycine) at 80A degrees C. A hydrolysis of 55\% for galactoxyloglucan (GXG) from tamarind kernel powder (TKP) was obtained in 12 h at 60A degrees C and 6 h at 70A degrees C using thermostable xyloglucanases, favouring a reduction in process time and enzyme dosage. The enzyme was stable in the presence of commercial detergents (Ariel), indicating its potential as an additive to laundry detergents.

}, keywords = {Alkalothermophilic Thermomonospora sp., Biotechnological applications, Purification, Thermostable, Xyloglucanase}, issn = {1431-0651}, doi = {10.1007/s00792-011-0413-0}, author = {Pol, Dipali and Menon, Vishnu and Rao, Mala} } @article { ISI:000310401100058, title = {Inhibition of xyloglucanase from an alkalothermophilic thermomonospora sp by a peptidic aspartic protease inhibitor from Penicillium sp VM24}, journal = {Bioresource Technology}, volume = {123}, year = {2012}, month = {NOV}, pages = {390-399}, publisher = {ELSEVIER SCI LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND}, abstract = {

A bifunctional inhibitor from Penicilliurn sp VM24 causing inactivation of xyloglucanase from Thermomonospora sp and an aspartic protease from Aspergillus saitoi was identified. Steady state kinetics studies of xyloglucanase and the inhibitor revealed an irreversible, non-competitive, two-step inhibition mechanism with IC50 and K-i; values of 780 and 500 nM respectively. The interaction of o-phthalaldehyde (OPTA)-labeled xyloglucanase with the inhibitor revealed that the inhibitor binds to the active site of the enzyme. Far- and near-UV spectrophotometric analysis suggests that the conformational changes induced in xyloglucanase by the inhibitor may be due to irreversible denaturation of enzyme. The bifunctional inhibitor may have potential as a biocontrol agent for the protection of plants against phytopathogenic fungi. (C) 2012 Elsevier Ltd. All rights reserved.

}, keywords = {Aspartic protease, Bifunctional inhibitor, Biocontrol agent, Inactivation mechanism, Xyloglucanase}, issn = {0960-8524}, doi = {10.1016/j.biortech.2012.07.050}, author = {Menon, Vishnu and Rao, Mala} }