The activity and half-life of pectate lyase (PL) from Bacillus megaterium were nine- and 60-fold, respectively, higher at 90°C in the presence of hydroxyapatite nanoparticles (NP-PLs) than in the presence of 1mM CaCl 2. Thermodynamic analysis of the nanoparticle-induced stability revealed an enhanced entropy-enthalpy compensation by the NP-PLs since a reciprocal linearity of the enthalpy-entropy change to 90°C was observed. Without nanoparticles, the linearity range was 70°C. Such compensation reflected the maintenance of the native structure of proteins. The remarkable enhancement of activity and stability of the NP-PL system at high temperatures may be utilized commercially e.g. in the food industry or the processing of natural fibers that may require a thermotolerant enzyme. © 2012 Elsevier Ltd.

A MUKHOPADHYAY

A K DASGUPTA

D CHATTOPADHYAY

K CHAKRABARTI

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Bioresource Technology

A purified calcium metalloprotease from Bacillus subtilis AKP(N) supplemented with hydroxyapatite nanoparticles [protease (+NP)] showed remarkable increase in thermostability (at 90 °C) over a broad alkaline pH range as compared to the non-supplemented enzyme. Thermodynamic analysis of the protease (+NP) showed decreases in Km and activation energy (Ea) with increased Vmax and deactivation energy (Ed) at both 40 °C and 90 °C. The protease (+NP) exhibited compatibility with various laboratory and commercial detergents (1%) at both 40 °C and 90 °C. The protease (+NP) was utilized to efficiently degrade feather to produce amino acids, removal of blood stains from cloth and tenderization of raw meat within a short time. © The Royal Society of Chemistry 2015.

RSC Advances

Enhancement of thermal and pH stability of an alkaline metalloprotease by nano-hydroxyapatite and its potential applications

A simple nanotechnology based immobilization technique for imparting psychrostability and enhanced activity to a psychrophilic laccase has been described here. Laccase from a psychrophile was supplemented with Copper oxide nanoparticles (NP) corresponding to copper (NP-laccase), the cationic activator of this enzyme and entrapped in single walled nanotube (SWNT). The activity and stability of laccase was enhanced both at temperatures as low as 4. °C and as high as 80. °C in presence of NP and SWNT. The enzyme could be released and re-trapped (in SWNT) multiple times while retaining significant activity. Laccase, immobilized in SWNT, retained its activity after repeated freezing and thawing. This unique capability of SWNT to activate and stabilize cold active enzymes at temperatures much lower or higher than their optimal range may be utilized for processes that require bio-conversion at low temperatures while allowing for shifts to higher temperature if so required. © 2014 Elsevier Ltd.

Enhanced functionality and stabilization of a cold active laccase using nanotechnology based activation-immobilization

An immobilization technique (using nanotechnology) that imparts psychrostability and enhanced activity to a psychrophilic pectate lyase (PL) has been described here. Pectate lyase from a pyscrophile was supplemented with calcium hydroxyapatite nanoparticles (NP-PL) as a substitute for Ca, (the cationic activator of this enzyme) and entrapped in single walled nanotube (SWNT) based molecular self-assembly. The activity and stability of PL was enhanced both at temperatures as low as 4°C and as high as 80°C in presence of NP and SWNT. The enzyme could be repeatedly released and re-trapped (in SWNT based molecular self-assembly) while retaining significant activity. The immobilized PL (in SWNT based molecular self-assembly), retained its activity after repeated freezing and thawing. This unique capability of SWNT to activate and stabilize a cold active enzyme at temperatures much lower or higher than its optimal range may be utilized for processes that require bio-conversion at low temperatures while simultaneously allowing for shifts to higher temperature. © 2015 Elsevier B.V.

Journal of Molecular Catalysis B: Enzymatic

Nanotechnology based activation-immobilization of psychrophilic pectate lyase: A novel approach towards enzyme stabilization and enhanced activity

Purified bacterial cellulase and xylanase were activated in the presence of calcium hydroxyapatite nanoparticles (NP) with concomitant increase in thermostability about 35% increment in production of d-xylose and reducing sugars from rice husk and rice straw was obtained at 80. °C by the sequential treatment of xylanase and cellulase enzymes in the presence of NP compared to the untreated enzyme sets. Our findings suggested that if the rice husk and the rice straw samples were pre-treated with xylanase prior to treatment with cellulase, the percentage increase of reducing sugar per 100. g of substrate (starting material) was enhanced by about 29% and 41%, respectively. These findings can be utilized for the extraction of reducing sugars from cellulose and xylan containing waste material. The purely enzymatic extraction procedure can be substituted for the harsh and bio-adverse chemical methods. © 2013.

Improved production of reducing sugars from rice husk and rice straw using bacterial cellulase and xylanase activated with hydroxyapatite nanoparticles

Banana, citrus and potato peels were subjected to treatment with hydroxyapatite nanoparticle (NP) supplemented purified pectate lyase (NP-PL), isolated from Bacillus megaterium AK2 to produce reducing sugar (RS). At both 50 and 90°C production of RS by NP-PL was almost twofold greater than that by untreated pectate lyase (PL) from each of the three peels. The optimal production of RS from banana and citrus peels were after 24 and 6. h of incubation while it was 24 and 4. h for potato peels at 50 and 90°C, respectively, on NP-PL treatment. NP-PL could degum raw, decorticated ramie fibers as well as enhance fiber tenacity and fineness. The weight loss of the fibers were 24% and 31% better (compared to PL treatment) after 24 and 48. h of processing. These findings have potential implications for the bio-ethanol, bio-fuel and textile industries. © 2013 Elsevier Ltd.

Degumming of ramie fiber and the production of reducing sugars from waste peels using nanoparticle supplemented pectate lyase

After 24 h of incubation with only purified pectate lyase isolated from Bacillus pumilus DKS1 (EF467045), the weight loss of the ramie fibre was found to be 25%. To know the catalytic residue of pectate lyase the pel gene encoding a pectate lyase from the strain Bacillus pumilus DKS1 was cloned in E. coli XL1Blue and expressed in E. coli BL21 (DE3) pLysS. The pel gene was sequenced and showed 1032 bp length. After purification using CM-Sepharose the enzyme showed molecular weight of 35 kDa and maximal enzymatic activity was observed at 60°C and a pH range of 8.5-9.0. Both Ca2+ and Mn2+ ions were required for activity on Na-pectate salt substrates, while the enzyme was strongly inhibited by Zn2+ and EDTA. The deduced nucleotide sequence of the DKS1 pectate lyase (EU652988) showed 90% homology to pectate lyases from Bacillus pumilus SAFR-032 (CP000813). The 3D structure as well as the catalytic residues was predicted using EasyPred software and Catalytic Site Atlas (CSA), respectively. Site directed mutagenesis confirmed that arginine is an essential catalytic residue of DKS1 pectate lyase. © 2010 Springer Science+Business Media B.V.

Biodegradation

Arg235 is an essential catalytic residue of Bacillus pumilus DKS1 pectate lyase to degum ramie fibre

An extracellular pectate lyase (EC 4.2.2.2) was purified from the culture filtrate of a newly isolated Bacillus pumilus DKS1 grown in pectin containing medium. Using ion-exchange and gel filtration chromatography, this enzyme was purified and found to have a molecular weight of around 35 kDa. The purified enzyme exhibited maximal activity at a temperature of 75 °C and pH 8.5. The presence of 1 mM calcium and manganese enhanced pectate lyase activity and was strongly inhibited by zinc, nickel and EDTA. The thermal inactivation studies revealed an entropy-enthalpy compensation pattern below a critical temperature. The alkaliphilicity and high thermostability of this pectate lyase may have potential implications in fibre degumming. © 2008 Elsevier Ltd. All rights reserved.

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ISSN	0960-8524