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.

A MUKHOPADHYAY

N DUTTA

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 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

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

The present study relates to a nanotechnology enabled method in which purified laccase from Escherichia coli AKL2 was supplemented with 100μM copper oxide nanoparticles (Cu2O) (NP-laccase). The activity, half life and stability of NP-laccase were enhanced by 4, 42 and 36-fold respectively at high temperature (80°C) and also over a wide range of pH (4-12) than laccase (in the presence of 0.18mM CuSO4). Thermodynamic analysis of the nanoparticle-induced enzyme stability revealed an enhanced entropy-enthalpy compensation at 80°C, which reflected the maintenance of its native structure. This was further supported by CD studies. The enhanced activity and thermostability of NP-laccase can be utilized for efficient decolorisation of dyes (both phenolic and azo). © 2012 Elsevier Ltd.

Thermostability, pH stability and dye degrading activity of a bacterial laccase are enhanced in the presence of Cu2O nanoparticles

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.

Improvement of thermostability and activity of pectate lyase in the presence of hydroxyapatite nanoparticles

A combined (enzymatic and chemical) process using a Bacillus pumilus strain (DKS1), isolated from the soil, was used to degum ramie bast fibres. After 24 h of incubation with the isolated pectinolytic strain using a low-cost medium, the weight loss of the ramie fibre was found to be 25% under small scale. High activity of pectate lyase was detected in the culture supernatants; 400 kg of ramie fibres was degummed with 24% weight loss in large-scale degumming under field conditions. No cellulase activity was found. Microbial intervention followed by mild (0.1%) alkali treatment showed high percentage of weight loss from the ramie fibre. Bacterial degumming followed by chemical treatment resulted in an increase of single fibre tenacity (cN/tex) by more than 20.81% as compared to non-degummed (decorticated) fibre samples. Scanning electron micrographs (SEM) and fluorescence microscope showed that after Bacillus pumilus DKS1 treatment the surface of the decorticated ramie fibre becomes very smooth. These results indicate the process provides an economical and eco-friendly method for the small scale as well as large-scale degumming of decorticated ramie fibre. This study has great relevance to the textile as well as paper industry. © Society for Industrial Microbiology 2008.

Journal	Data powered by TypesetBioresource Technology
Publisher	Data powered by TypesetElsevier Ltd
ISSN	0960-8524