Oxidative biodegradation of single-walled carbon nanotubes by partially purified lignin peroxidase from Sparassis latifolia mushroom

Gayathri Chandrasekaran,최수경,이영철,김근중,신현재 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.5

Two types of carbon nanotubes (usually single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs)) have been intensively focused on academic researches and mass-produced for wide applications such as composite materials, biosensors, and drug delivery systems. However, due to oxidative stress-dependent and physically-induced cellular toxicity of CNTs, many efforts to render biocompatible and biodegradable properties in CNTs have been highlighted. Thus, taking into the consideration of exposure in human health and the environment, biodegradation of CNTs as a potential disposal is highly addressed. In this study, lignin peroxidase (LiP) was isolated and partially purified from the fruiting bodies of the edible mushroom Sparassis latifolia (S. latifolia). The biodegradation of raw grade and thermally-treated carboxylated SWCNTs (denoted as ASA and AST) with this enzyme was investigated, prior to more biodegradation-resistant MWCNTs. The interactions between the SWCNTs and LiP were investigated using various techniques, and the intermediate byproducts of the LiP degradation were identified. Our findings demonstrated that both ASA and AST were efficiently degraded by LiP where the producing radicals by the LiP played a critical role in the biodegradation of SWCNTs. The final degraded products were confirmed with the generation of CO2 gas. Conclusively, the low extraction cost of partially purified enzyme from mushrooms can make this approach a promising alternative in environmental bioremediation as a practical application.

Complete genome sequence of Microvirga sp. 17mud 1-3, a radiation-resistant bacterium

Gayathri Sathiyaraj,Myung Kyum Kim,Ju-Young Kim,Su Jeong Kim,장준휘,Soohyun Maeng,Myung-Suk Kang,Sathiyaraj Srinivasan 대한독성 유전단백체 학회 2018 Molecular & cellular toxicology Vol.14 No.3

Backgrounds: The genera Deinococcus Hymenobacter, Spirosoma, and Rubrobacter are renowned as an extremophilic bacteria. Most of the species of these genera have been shown to be either gamma radiation resistant or UV radiation resistant or both. Strain 17mud 1-3 was isolated from gamma-irradiated mud sample collected at Boryeong beach, South Korea. Methods: The genome of strain 17mud 1-3 was sequenced and assembled using Pacific Biosciences RS II system. The genome sequence was annotated using Genomes-Expert Review (IMG-ER) platform, Prodigal, and JGI GenePRIMP pipeline. The protein-coding genes were identified using Prodigal, Pfam and COG databases implemented in the IMG systems. Results: The complete genome consists of a circular chromosome (4,403,107 bp) encoding 4,368 coding sequences (CDs) and 4,301genes. Conclusion: The new strains showed both gamma and UV-C irradiation resistance and their complete genome sequence annotation features showed the presence of the genes involved in the radiation-resistance.

Purification and characterization of lignin peroxidase from Sparassis crispa mushroom

Gayathri CHANDRASEKARAN,Hyun-Jae SHIN 한국생물공학회 2011 한국생물공학회 학술대회 Vol.2011 No.4

Complete genome sequence of Nibribacter radioresistens DG15C, a radiation resistant bacterium

Gayathri Sathiyaraj,Myung Kyum Kim,Ju-Young Kim,Su Jeong Kim,장준휘,Soohyun Maeng,Myung-Suk Kang,Sathiyaraj Srinivasan 대한독성 유전단백체 학회 2018 Molecular & cellular toxicology Vol.14 No.3

Backgrounds: The ionizing radiation from the gamma rays is damaging the genetic materials of the cells, possibly leading to cell death and cause permanent changes within daughter cells. A red pigmented, Gramnegative, aerobic, short-rod shaped, non-motile, UV and gamma radiation tolerant bacterium Nibribacter radioresistens DG15C was isolated from a soil sample collected in a rice field in South Korea. Methods: The complete genome of DG15C was sequenced and assembled using Pacific Biosciences RS II system. The genome sequence was annotated using Genomes-Expert Review (IMG-ER) platform, Prodigal, and JGI GenePRIMP pipeline. The protein-coding genes were identified using Prodigal, Pfam and COG databases implemented in the IMG systems. Results: The complete genome sequence of strain DG15C consists of a circular chromosome (4,143,738 bp) encoding 3,969 coding sequences (CDs) and 3,582 genes. The bacterium showed resistance to gamma and UVC radiations. Conclusion: The genome annotation as confirmed the presence of gene clusters involved in the toxicity resistance of radiation.

Oxidative biodegradation of single-walled carbon nanotubes by partially purified lignin peroxidase from Sparassis latifolia mushroom’

Gayathri Chandrasekaran,신현재,최수경,이영철,김근중 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.32 No.-

Two types of carbon nanotubes (usually single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs)) have been intensively focused on academic researches and mass-produced for wide applications such as composite materials, biosensors, and drug delivery systems. However, due to oxidative stress-dependent and physically-induced cellular toxicity of CNTs, many efforts to render biocompatible and biodegradable properties in CNTs have been highlighted. Thus, taking into the consideration of exposure in human health and the environment, biodegradation of CNTs as a potential disposal is highly addressed. In this study, lignin peroxidase (LiP) was isolated and partially purified from the fruiting bodies of the edible mushroom Sparassis latifolia (S. latifolia). The biodegradation of raw grade and thermally-treated carboxylated SWCNTs (denoted as ASA and AST) with this enzyme was investigated, prior to more biodegradation-resistant MWCNTs. The interactions between the SWCNTs and LiP were investigated using various techniques, and the intermediate by-products of the LiP degradation were identified. Our findings demonstrated that both ASA and AST were efficiently degraded by LiP where the producing radicals by the LiP played a critical role in the biodegradation of SWCNTs. The final degraded products were confirmed with the generation of CO2 gas. Conclusively, the low extraction cost of partially purified enzyme from mushrooms can make this approach a promising alternative in environmental bioremediation as a practical application.

Outside the net: Intersectionality and inequality in the fisheries of Trincomalee, Sri Lanka

Gayathri Lokuge,Dorothea Hilhorst 이화여자대학교 아시아여성학센터 2017 Asian Journal of Women's Studies(AJWS) Vol.23 No.4

Inequality and conflict in Sri Lanka have frequently been analyzed along ethnic lines. However, many scholars have stressed the importance of other dimensions of identity, such as gender, caste and class, in studying social tension. This study uses intersectionality theory to examine how a combination of the social categories of gender, race, ethnicity and location creates structural inequality. This article draws upon in-depth research on Muslim, Tamil, Sinhalese and indigenous/Veder women who catch and market fish in the conflict-affected eastern district of Trincomalee, Sri Lanka. The focus was on intra-group differences among these women and the different sources of power they use to subvert existing power structures. Although multiple inequalities affected the respondents’ daily lives and participation in activities, they were not passive victims; they used their own agency to negotiate for their livelihoods. Nevertheless, the women who comprise the focus of this study appeared to be completely invisible to government fisheries management bodies. The lack of institutional representation has disadvantaged them in their negotiations for space to engage in livelihood activities. Registration of these women by the government department of fisheries among those who make a living from fishing would provide them with a first measure of recognition and empowerment, strengthening their chances of negotiating access to the fishery livelihood resources.

Experiments and modeling of a vacuum membrane distillation for high saline water

Gayathri Naidu,최용준,정상현,황태문,Saravanamuthu Vigneswaran 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.4

A modified design vacuum membrane distillation (VMD) system with high saline water was evaluated using different operating conditions (sustainable low feed temperature and flow velocity). At high salinity, a permeate flux of 13.9 to 15.8 L m-2 h-1 was achieved. Increasing the salinity from 1 to 3 M NaCl reduced the permeate flux by 18–20%. An increase in bulk feed temperature (310.2–319.2 K) significantly increased the permeate flux by 64%. The increase in flow velocity (1.1 to 2.2 m s-1) in turn increased the permeate flux by 14–20%. Model fluxes predicted was a good fit to experimental fluxes (R2 ≥ 0.94).

Study on the Indian Aviation Industry Prospects

Gayathri Gopalakrishnan,Anthony Boocock 동중앙아시아경상학회 2016 한몽경상학회 학술대회 Vol.2016 No.11

Mesoporous nitrogen-doped carbon@graphene nanosheets as ultra-stable anode for lithium-ion batteries – Melamine as surface modifier than nitrogen source

Gayathri, Sampath,Arunkumar, Paulraj,Kim, Eui Joong,Kim, Sumin,Kang, Inji,Han, Jong Hun Elsevier 2019 ELECTROCHIMICA ACTA Vol.318 No.-

<P><B>Abstract</B></P> <P>Nitrogen-doped carbon materials are highly appealing next-generation anode for Li-ion battery owing to high energy density, conducting and porous structure, and a large number of ion-binding sites. However, the formation of micropores limits the ion/electrolyte diffusion at high discharge rate leading to underutilization of active material, capacity fading, and low cycle stability, hindering their practical application. Herein, we report mesoporous-rich carbon hybrid comprising of zeolitic imidazolate framework (ZIF)-derived nitrogen-doped carbon-anchored graphene using melamine as the surface modifier and pore expander. A high specific capacity of 775 (after 1100 cycles) and 675 mAh g<SUP>−1</SUP> (after 1000 cycles) were obtained at current densities of 1000 and 2000 mA g<SUP>−1</SUP> (4C) which is two-fold higher than the initial capacity. The melamine-modified anode exhibited excellent cycle retention of 163% at 1000 mA g<SUP>−1</SUP> after 800 cycles, compared to 91% for the unmodified anode, indicating the activation process through the mesoporous channels. Superior cycle retention and long cycle life were attributed to the melamine-induced features <I>viz</I> mesoporous structure and defective sites formed on carbon/graphene facilitating efficient electrolyte percolation/ion transport and Li-ion storage, respectively. This strategy provides a promising approach for the design of ZIFs-derived carbon materials for high-performance Li-ion batteries.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Melamine acts as pore expander and surface modifier. </LI> <LI> Melamine-induced mesoporous structure and functionalized carbon anode material. </LI> <LI> Melamine-tailored carbon exhibited superior lithium storage performance. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Mesoporous nitrogen-doped carbon-anchored graphene anode derived from melamine as pore modifier exhibited superior cycle retention and long cycle life for high power lithium-ion battery.</P> <P>[DISPLAY OMISSION]</P>

Crystallization/aggregation enhanced emissive smart fluorophores for rewritable fluorescent platform: Alkoxy chain length controlled solid state fluorescence

Gayathri, Parthasarathy,Hariharan, Palamarneri Sivaraman,Moon, Dohyun,Anthony, Savarimuthu Philip Elsevier 2019 Journal of luminescence Vol.211 No.-

<P><B>Abstract</B></P> <P>Aggregation enhanced emissive (AEE) triphenylamine-phenylacetonitrile based donor-accepter compounds showed alkoxy chain length dependent solid state fluorescence efficiency and stimuli induced off-on fluorescence switching. Molecular conformational and packing differences lead to fluorescence tuning between 480 and 530 nm. The compounds exhibited off-on mechanofluorochromism upon crushing and heating. Interestingly, all compounds produced stable non-fluorescent melt that was converted to strongly fluorescent solids upon crystallization. The high-contrast off-on crystallization induced fluorescence switching has been used to demonstrate rewritable fluorescence platform. Single crystal structural analysis, powder X-ray diffraction and differential scanning calorimetry have been performed to understand the mechanism of fluorescence switching.</P> <P><B>Graphical abstract</B></P> <P>Crystallization induced fluorescence switching of alkoxy chain substituted triphenylamine smart fluorophores have been used to demonstrate rewritable fluorescent platform.</P> <P>[DISPLAY OMISSION]</P>