Dr. Harikrishnan Hariharan | Anna University (original) (raw)

Papers by Dr. Harikrishnan Hariharan

International Journal of Environmental Technology and Management

Energy, Environment, and Sustainability, 2019

Biofuel is an important solution to the fuel crisis which may affect the future generation. Also ... more Biofuel is an important solution to the fuel crisis which may affect the future generation. Also production of biofuel will greatly reduce the need and dependency of fossil fuels. It also can greatly reduce the environmental pollution. Different types of biofuels include bioethanol, biodiesel, biogas and biobutanol. Biodiesel is a very good replacement fuel for petroleum and also produce less toxins and a biodegradable one. Thus bioethanol is a clean gas produced through fermentation technology. High energy biofuel, biobutanol can also be produced by the fermentation of agricultural residues. All these energy rich high value fuels can be produced from agricultural wastes, which are getting wasted as such in the nature. The current chapter mainly deals with different ways in which biofuels can be produced using agricultural waste thereby making entire process cost effective and economical. This can make every country independent for biofuel production making the nature stable for future generation.

The present study focused on the the characterization of Indole acetic acid (IAA) production unde... more The present study focused on the the characterization of Indole acetic acid (IAA) production under in vitro condition. A total of 90 actinomycetes was isolated from rice rhizosphere, which was collected from rice fields in the southern districts of Tamil Nadu, India. All isolates were screened for antagonism towards phytofungal pathogens such as Rhizoctonia solani, Macrophomina phaseolina, Fusarium oxysporum, Fusarium udum and Alternaria alternata. Out of 95 isolates, 65 were found to be producing IAA was confirmed by colorimetric method. Isolate VSMGT1014 produced IAA in the ISP-2 medium supplemented with 0.5% L tryptophan in the amount of 15.96 µg/ml. The ISP-2 medium was recorded as the best medium for production of IAA, where the maximum IAA production was recorded at 30 °C and pH 8 for the production of 4.76 µg/ml and 26.63 µg/ml respectively. The specific spot was found from the extracted IAA has similarity to authentic IAA with the same Rf value of 0.92. High performance liqu...

South Indian Journal of Biological Sciences, 2015

Bacillus pasteurii concrete durability calcite precipitation As like humans having the ability to... more Bacillus pasteurii concrete durability calcite precipitation As like humans having the ability to precipitate minerals in the form of bones and teeth continuously, even some bacteria like Bacillus pasteurii and Bacillus sphaericus can continuously precipitate calcite, called as microbiological induced calcite precipitation. The present investigation discusses on the effects of B. pasteurii and B. sphaericus on durability of concrete beams. The efficacy of the bio deposition treatment on concrete beams with bacteria, alkali, sulfate and freeze-thaw environments along with water absorption was studied. The presence of a layer of calcium carbonate and microbial biomass resulted in a decrease of permeation properties of cementation materials. This technique not only improved the concrete strength but also enhanced water impermeability through calcite precipitation, quantified by X-ray diffraction analysis. Hence this biological treatment is highly desirable and eco-friendly. The present work guarantees a biological metabolic outcome with improvement in concrete and building material technology.

Journal of basic microbiology, Jan 2, 2015

The efficacy of a rhizobacterium Streptomyces aurantiogriseus VSMGT1014 for the production of bio... more The efficacy of a rhizobacterium Streptomyces aurantiogriseus VSMGT1014 for the production of bioactive metabolites with antifungal properties was evaluated under in vitro conditions. The production of bioactive metabolites by S. aurantiogriseus VSMGT1014 in International Streptomyces Project-2 (ISP-2) broth, supplemented with glucose and ammonium acetate was found to be the most suitable carbon and nitrogen sources for the maximum production of bioactive metabolites against rice pathogen, Rhizoctonia solani. The zone of inhibition range from 23.5 to 28.5 mm and 10.3 to 18.3 mm for glucose and ammonium acetate supplemented media, respectively. The culture filtrate of S. aurantiogriseus VSMGT1014 at pH 7.5, 37 °C at 120 rpm in 6 days of incubation showed the maximum production of bioactive metabolites with antagonistic potential. The crude metabolite was characterized by different spectral studies such as Ultraviolet spectrum, infrared-spectrum and based on the different analytical t...

Sustainable Approaches to Controlling Plant Pathogenic Bacteria, 2015

Siderophore is an iron-healing compound that has an immense role in micro-bial interaction, espec... more Siderophore is an iron-healing compound that has an immense role in micro-bial interaction, especially in the rhizosphere. Siderophore is present in one of the major mechanisms of bacteria that is involved in the biological control of plant diseases. Both plant pathogenic fungi and bacteria are reported to be inhibited by siderophore-producing biocon-trol agents. These siderophores are produced in iron-limited conditions to sequester the CONTENTS 8.1 Iron Importance ....................................................................................................................168 8.2 Siderophore ...........................................................................................................................168 8.2.1 Siderophores: Structures and Binding Sites .............................................................169 8.2.2 Hydroxymate Siderophore ........................................................................................169 8.2.3 Catecholate Siderophores .........................................................................................170 8.2.4 Carboxylate (Complexion) Siderophore ....................................................................170 8.2.5 Mixed Siderophores ..................................................................................................170 8.2.6 Pyoverdin ..................................................................................................................170 8.2.7 Siderophore Biosynthesis ..........................................................................................171 8.2.8 Mechanism of Siderophore Export ...........................................................................171 8.2.9 Transport of Iron-Siderophore Complex ..................................................................172 8.2.10 Metabolism of Iron ...................................................................................................173 8.2.11 Iron Regulation in Bacteria ......................................................................................173 8.3 Applications of Siderophore .................................................................................................174 8.4 Mechanisms of Siderophore in Biocontrol: Overview .........................................................175 8.5 Phytopathology .....................................................................................................................176 8.6 Bacteria–Pathogen Interactions ............................................................................................177 8.6.1 Bacterial Soft Rot of Potato ......................................................................................177 8.6.2 Tomato Bacterial Wilt ...............................................................................................177 8.6.3 Rice Bacterial Blight ................................................................................................178 8.6.4 Bacterial Canker of Tomato ......................................................................................179 8.6.5 Bacterial Blight of Cotton .........................................................................................179 8.6.6 Bacterial Leaf Spot of Mungbean.............................................................................180 8.6.7 Fire Blight Disease ...................................................................................................180 8.7 Conclusion ............................................................................................................................181 Acknowledgments ..........................................................................................................................181 References ......................................................................................................................................181 168 Sustainable Approaches to Controlling Plant Pathogenic Bacteria less-available iron from the environment and thereby deprive the pathogen of iron, which ulti-mately leads to inhibition. Three main groups of siderophores have been reported: hydroxy-mate siderophore, catecholate siderophore, and mixed siderophore. Siderophores are synthesized through two different biosynthetic pathways: NRPSs-dependent and non-NRPSs-dependent. The ABC-type transporter proteins are also involved in the delivery of iron-sider-ophore complex into the cytosol of the producing organism, where it can be utilized. Some pathogenic bacteria capable of producing siderophores are highly virulent. Siderophore inter-acts with the H2O2 and peroxidases in the affected tissue either to enhance oxidative stress induced by harpin, coded by an hrpNgene, or to protect bacterial cells by inhibiting the generation of reactive oxygen species. In this chapter we discuss control of bacterial plant pathogens with the production of siderophore by antagonistic rhizobacterium. Emphasis is given to the most…

Biological application of nanoparticles is very much interesting and increasingly recognized for ... more Biological application of nanoparticles is very much interesting and increasingly recognized for their utility especially in bio-nanomedicine. The present investigation was biological synthesis of cadmium nanoparticles using Bacillus cereus and toxic effect on prokaryotic pathogens. UV spectrum, XRD and SEM analysis of the cadmium sulfide nanoparticles indicated that they are in varying size from 30 to 100 nm size. Antibacterial activity of Cds nanoparticles against three clinical isolates of Gram positive Staphylococcus aureus bacterial isolates and two Pseudomonas aeruginosa, isolates analyzed. Gram positive Staphylococcus aureus was sensitive than Gram negative Pseudomonas aeruginosa. Pseudomonas species showed higher inhibitory effect than Staphylococcal isolates.

ABSTRACT Dried and ground peel biomass, ripe waste banana and Hydrolyzed peels of green and red b... more ABSTRACT Dried and ground peel biomass, ripe waste banana and Hydrolyzed peels of green and red banana used for bio ethanol production by Saccharomyces cerevisiae with shake flask culture. The substrate was given with different concentration as 1%, 2.5%, 5%, 7.5% and 10% (w/v) along with 1% inoculum. Saccharomyces cerevisiae exhibited maximum yield of ethanol in ripened red banana and their hydrolyzed peels about 1.3% and 0.27% (v/v) in 10% substrate concentration. The minimum yield about 0.02% of alcohol was produced in green un hydrolyzed banana peels with 1% substrate concentration. Conversion of reducing sugar range was 21% (g %) in un hydrolyzed green banana peels and maximum of 76% in red ripened banana as a substrate.

Prospects in Bioscience: Addressing the Issues, 2012

Presently actinomycetes from rice rhizosphere are screened for novel bioactive secondary metaboli... more Presently actinomycetes from rice rhizosphere are screened for novel bioactive secondary metabolites and for biocontrol potential against fungal plant pathogens. A total of 102 actinomycetes were isolated from rice rhizosphere soils collected from Tamil Nadu, India. All the isolates were screened against sheath blight pathogen Rhizoctonia solani by dual culture method with inhibition zone range from 0.6 to 3.0 cm. Among 102, 56 have shown the antagonistic activity against R. solani. Due to superior biocontrol activity against fungal pathogens over the other actinomycetes, an efficient strain VSMGT1014 was selected and identified as Streptomyces sp. based on the biochemical and atomic force microscope observation. The culture filtrate of Streptomyces sp. VSMGT1014 remarkably inhibited the mycelial growth and conidial and sclerotial germination of many fungal pathogens such as Macrophomina phaseolina, Fusarium oxysporum, Fusarium udum, and Alternaria alternata. The strain Streptomyces sp.VSMGT1014 produced five different compounds with Rf value ranges: 0.46, 0.51, 0.61, 0.85, and 0.89. Ethyl acetate extract of crude metabolite from VSMGT1014 significantly inhibited the mycelia growth of most of the fungal pathogens as well as sclerotial germination of R. solani.

World Journal of Microbiology and Biotechnology, 2014

A total of 132 actinomycetes was isolated from different rice rhizosphere soils of Tamil Nadu, In... more A total of 132 actinomycetes was isolated from different rice rhizosphere soils of Tamil Nadu, India, among which 57 showed antagonistic activity towards Rhizoctonia solani, which is sheath blight (ShB) pathogen of rice and other fungal pathogens such as Macrophomina phaseolina, Fusarium oxysporum, Fusarium udum and Alternaria alternata with a variable zone of inhibition. Potential actinomycete strain VSMGT1014 was identified as Streptomyces aurantiogriseus VSMGT1014 based on the morphological, physiological, biochemical and 16S rRNA sequence analysis. The strain VSMGT1014 produced lytic enzymes, secondary metabolites, siderophore, volatile substance and indole acetic acid. Crude metabolites of VSMGT1014 showed activity against R. solani at 5 µg ml(-1); however, the prominent inhibition zone was observed from 40 to 100 µg ml(-1). Reduced lesion heights observed in culture, cells-free filtrate, crude metabolites and carbendazim on challenge with pathogen in the detached leaf assay. The high content screening test clearly indicated denucleation of R. solani at 5 µg ml(-1) treatment of crude metabolite and carbendazim respectively. The results conclude that strain VSMGT1014 was found to be a potential candidate for the control of ShB of rice as a bio fungicide.

Bioorganic & Medicinal Chemistry Letters, 2014

BMC Infectious Diseases, 2014

Prospects in Bioscience: Addressing the Issues, 2012

ABSTRACT Abstract The study of root-associated bacteria and their antagonistic potential is impor... more ABSTRACT Abstract The study of root-associated bacteria and their antagonistic potential is important not only for understanding their ecological role in the rhizosphere and the interaction with plants but also for the suppression of soilborne plant pathogens. In this context, a total of 206 fluorescent pseudomonads (FPs) were isolated from rice rhizosphere from southern part of Tamil Nadu. Initially 113 isolates were found which were active against Rhizoctonia solani, of which 89 were strongly active against R. solani with zone of inhibition range from 10 to 32 mm. Production of lytic enzymes such as chitinase, cellulase, protease, amylase and pectinase was reported along with other characteristics including phosphate solubilisation and siderophore formation in 89 antagonistic fluorescent pseudomonads. Antagonistic fluorescent pseudomonads were also tested towards other fungal pathogens such as Macrophomina phaseolina, Fusarium oxysporum, Fusarium udum and Alternaria alternata. Among 89 the strain VSMKU-4046 has high antagonistic potential against R. solani. Strain VSMKU-4046 significantly controls sheath blight of rice compared to control using sclerotia of R. solani through detached leaf assay. The lesion length around the sclerotium was measured, and ShB severity was rated by the relative lesion height (RLH) method with the following formula:% RLH = 100 x Total height of lesions / Total leaf height. %RLH=100×totalheightoflesions/totalleafheight

Chinese Chemical Letters, 2014

An eco-friendly water mediated synthesis of 1,2,3-triazolyl-2-aminopyrimidine hybrids as highly p... more An eco-friendly water mediated synthesis of 1,2,3-triazolyl-2-aminopyrimidine hybrids as highly potent anti-bacterial agents

Chalcogenide Letters, Dec 1, 2012

In the area of nanotechnology, the development of techniques for the controlled synthesis of meta... more In the area of nanotechnology, the development of techniques for the controlled synthesis of metal nanoparticles of well-defined size, shape and composition is a big challenge. Metal nanoparticles and nanocomposites exhibit unique electronic, magnetic, catalytic and optical properties that are different from those of bulk metals. This could result in interesting new applications that could potentially be utilized in the biomedical sciences and areas such as optics and electronics [1]. Nanomaterials are at the leading edge of the rapidly developing ...

Springer Proceedings in Energy, 2020

The present investigation aims to produce an alternative fuel in the form of biofuels from cassav... more The present investigation aims to produce an alternative fuel in the form of biofuels from cassava and sweet potato by simultaneous saccharification and fermentation (SSF). Sweet potato and cassava are one of the richest sources of starch for production of bioethanol. The work highlights the novelty factor of coupled reaction stage in the production of bioethanol. Amylase-producing fluorescent pseudomonads was isolated, and the process parameters were optimized to get maximum ethanol yield. The dry matter ratio of cassava as well as sweet potato to water from 1:10 to 1:2 (w/v) was studied, respectively. Fresh raw materials were dried at 50 °C and assayed. At ratios of 1:6, similar results for both sources in terms of ethanol concentration (30–35 g/L), fermentation time (24 h) and complete sugar conversion were found. The results showed that sweet potato is a suitable source which showed significantly higher ethanol production yield.

e-Journal of Surface Science and Nanotechnology, 2015

The series Springer Proceedings in Energy covers a broad range of multidisciplinary subjects in t... more The series Springer Proceedings in Energy covers a broad range of multidisciplinary subjects in those research fields closely related to present and future forms of energy as a resource for human societies. Typically based on material presented at conferences, workshops and similar scientific meetings, volumes published in this series will constitute comprehensive state-of-the-art references on energy-related science and technology studies. The subjects of these conferences will fall typically within these broad categories:

The efficacy of a rhizobacteriumStreptomyces aurantiogriseusVSMGT1014 for the production of bioac... more The efficacy of a rhizobacteriumStreptomyces aurantiogriseusVSMGT1014 for the production of
bioactive metabolites with antifungal properties was evaluated underin vitro conditions. The
production of bioactive metabolites by S. aurantiogriseus VSMGT1014 in International
Streptomyces Project-2 (ISP-2) broth, supplemented with glucose and ammonium acetate was
found to be the most suitable carbon and nitrogen sources for the maximum production of
bioactive metabolites against rice pathogen,Rhizoctonia solani. The zone of inhibition range from
23.5 to 28.5mm and 10.3 to 18.3mm for glucose and ammonium acetate supplemented media,
respectively. The culturefiltrate of S. aurantiogriseusVSMGT1014 at pH 7.5, 37 °C at 120 rpm in
6 days of incubation showed the maximum productionof bioactive metaboliteswith antagonistic
potential. The crude metabolitewas characterizedby different spectral studies suchasUltraviolet
spectrum, infrared-spectrum and based on the different analytical techniques, including thin
layer chromatography (TLC) and high performance liquid chromatography (HPLC) with the
retention time 29.4 and the bioactive metabolite was identified as phenazine, which was
confirmed by pure phenazine compound as positive control.

International Journal of Environmental Technology and Management

Energy, Environment, and Sustainability, 2019

Biofuel is an important solution to the fuel crisis which may affect the future generation. Also ... more Biofuel is an important solution to the fuel crisis which may affect the future generation. Also production of biofuel will greatly reduce the need and dependency of fossil fuels. It also can greatly reduce the environmental pollution. Different types of biofuels include bioethanol, biodiesel, biogas and biobutanol. Biodiesel is a very good replacement fuel for petroleum and also produce less toxins and a biodegradable one. Thus bioethanol is a clean gas produced through fermentation technology. High energy biofuel, biobutanol can also be produced by the fermentation of agricultural residues. All these energy rich high value fuels can be produced from agricultural wastes, which are getting wasted as such in the nature. The current chapter mainly deals with different ways in which biofuels can be produced using agricultural waste thereby making entire process cost effective and economical. This can make every country independent for biofuel production making the nature stable for future generation.

The present study focused on the the characterization of Indole acetic acid (IAA) production unde... more The present study focused on the the characterization of Indole acetic acid (IAA) production under in vitro condition. A total of 90 actinomycetes was isolated from rice rhizosphere, which was collected from rice fields in the southern districts of Tamil Nadu, India. All isolates were screened for antagonism towards phytofungal pathogens such as Rhizoctonia solani, Macrophomina phaseolina, Fusarium oxysporum, Fusarium udum and Alternaria alternata. Out of 95 isolates, 65 were found to be producing IAA was confirmed by colorimetric method. Isolate VSMGT1014 produced IAA in the ISP-2 medium supplemented with 0.5% L tryptophan in the amount of 15.96 µg/ml. The ISP-2 medium was recorded as the best medium for production of IAA, where the maximum IAA production was recorded at 30 °C and pH 8 for the production of 4.76 µg/ml and 26.63 µg/ml respectively. The specific spot was found from the extracted IAA has similarity to authentic IAA with the same Rf value of 0.92. High performance liqu...

South Indian Journal of Biological Sciences, 2015

Bacillus pasteurii concrete durability calcite precipitation As like humans having the ability to... more Bacillus pasteurii concrete durability calcite precipitation As like humans having the ability to precipitate minerals in the form of bones and teeth continuously, even some bacteria like Bacillus pasteurii and Bacillus sphaericus can continuously precipitate calcite, called as microbiological induced calcite precipitation. The present investigation discusses on the effects of B. pasteurii and B. sphaericus on durability of concrete beams. The efficacy of the bio deposition treatment on concrete beams with bacteria, alkali, sulfate and freeze-thaw environments along with water absorption was studied. The presence of a layer of calcium carbonate and microbial biomass resulted in a decrease of permeation properties of cementation materials. This technique not only improved the concrete strength but also enhanced water impermeability through calcite precipitation, quantified by X-ray diffraction analysis. Hence this biological treatment is highly desirable and eco-friendly. The present work guarantees a biological metabolic outcome with improvement in concrete and building material technology.

Journal of basic microbiology, Jan 2, 2015

The efficacy of a rhizobacterium Streptomyces aurantiogriseus VSMGT1014 for the production of bio... more The efficacy of a rhizobacterium Streptomyces aurantiogriseus VSMGT1014 for the production of bioactive metabolites with antifungal properties was evaluated under in vitro conditions. The production of bioactive metabolites by S. aurantiogriseus VSMGT1014 in International Streptomyces Project-2 (ISP-2) broth, supplemented with glucose and ammonium acetate was found to be the most suitable carbon and nitrogen sources for the maximum production of bioactive metabolites against rice pathogen, Rhizoctonia solani. The zone of inhibition range from 23.5 to 28.5 mm and 10.3 to 18.3 mm for glucose and ammonium acetate supplemented media, respectively. The culture filtrate of S. aurantiogriseus VSMGT1014 at pH 7.5, 37 °C at 120 rpm in 6 days of incubation showed the maximum production of bioactive metabolites with antagonistic potential. The crude metabolite was characterized by different spectral studies such as Ultraviolet spectrum, infrared-spectrum and based on the different analytical t...

Sustainable Approaches to Controlling Plant Pathogenic Bacteria, 2015

Siderophore is an iron-healing compound that has an immense role in micro-bial interaction, espec... more Siderophore is an iron-healing compound that has an immense role in micro-bial interaction, especially in the rhizosphere. Siderophore is present in one of the major mechanisms of bacteria that is involved in the biological control of plant diseases. Both plant pathogenic fungi and bacteria are reported to be inhibited by siderophore-producing biocon-trol agents. These siderophores are produced in iron-limited conditions to sequester the CONTENTS 8.1 Iron Importance ....................................................................................................................168 8.2 Siderophore ...........................................................................................................................168 8.2.1 Siderophores: Structures and Binding Sites .............................................................169 8.2.2 Hydroxymate Siderophore ........................................................................................169 8.2.3 Catecholate Siderophores .........................................................................................170 8.2.4 Carboxylate (Complexion) Siderophore ....................................................................170 8.2.5 Mixed Siderophores ..................................................................................................170 8.2.6 Pyoverdin ..................................................................................................................170 8.2.7 Siderophore Biosynthesis ..........................................................................................171 8.2.8 Mechanism of Siderophore Export ...........................................................................171 8.2.9 Transport of Iron-Siderophore Complex ..................................................................172 8.2.10 Metabolism of Iron ...................................................................................................173 8.2.11 Iron Regulation in Bacteria ......................................................................................173 8.3 Applications of Siderophore .................................................................................................174 8.4 Mechanisms of Siderophore in Biocontrol: Overview .........................................................175 8.5 Phytopathology .....................................................................................................................176 8.6 Bacteria–Pathogen Interactions ............................................................................................177 8.6.1 Bacterial Soft Rot of Potato ......................................................................................177 8.6.2 Tomato Bacterial Wilt ...............................................................................................177 8.6.3 Rice Bacterial Blight ................................................................................................178 8.6.4 Bacterial Canker of Tomato ......................................................................................179 8.6.5 Bacterial Blight of Cotton .........................................................................................179 8.6.6 Bacterial Leaf Spot of Mungbean.............................................................................180 8.6.7 Fire Blight Disease ...................................................................................................180 8.7 Conclusion ............................................................................................................................181 Acknowledgments ..........................................................................................................................181 References ......................................................................................................................................181 168 Sustainable Approaches to Controlling Plant Pathogenic Bacteria less-available iron from the environment and thereby deprive the pathogen of iron, which ulti-mately leads to inhibition. Three main groups of siderophores have been reported: hydroxy-mate siderophore, catecholate siderophore, and mixed siderophore. Siderophores are synthesized through two different biosynthetic pathways: NRPSs-dependent and non-NRPSs-dependent. The ABC-type transporter proteins are also involved in the delivery of iron-sider-ophore complex into the cytosol of the producing organism, where it can be utilized. Some pathogenic bacteria capable of producing siderophores are highly virulent. Siderophore inter-acts with the H2O2 and peroxidases in the affected tissue either to enhance oxidative stress induced by harpin, coded by an hrpNgene, or to protect bacterial cells by inhibiting the generation of reactive oxygen species. In this chapter we discuss control of bacterial plant pathogens with the production of siderophore by antagonistic rhizobacterium. Emphasis is given to the most…

Biological application of nanoparticles is very much interesting and increasingly recognized for ... more Biological application of nanoparticles is very much interesting and increasingly recognized for their utility especially in bio-nanomedicine. The present investigation was biological synthesis of cadmium nanoparticles using Bacillus cereus and toxic effect on prokaryotic pathogens. UV spectrum, XRD and SEM analysis of the cadmium sulfide nanoparticles indicated that they are in varying size from 30 to 100 nm size. Antibacterial activity of Cds nanoparticles against three clinical isolates of Gram positive Staphylococcus aureus bacterial isolates and two Pseudomonas aeruginosa, isolates analyzed. Gram positive Staphylococcus aureus was sensitive than Gram negative Pseudomonas aeruginosa. Pseudomonas species showed higher inhibitory effect than Staphylococcal isolates.

ABSTRACT Dried and ground peel biomass, ripe waste banana and Hydrolyzed peels of green and red b... more ABSTRACT Dried and ground peel biomass, ripe waste banana and Hydrolyzed peels of green and red banana used for bio ethanol production by Saccharomyces cerevisiae with shake flask culture. The substrate was given with different concentration as 1%, 2.5%, 5%, 7.5% and 10% (w/v) along with 1% inoculum. Saccharomyces cerevisiae exhibited maximum yield of ethanol in ripened red banana and their hydrolyzed peels about 1.3% and 0.27% (v/v) in 10% substrate concentration. The minimum yield about 0.02% of alcohol was produced in green un hydrolyzed banana peels with 1% substrate concentration. Conversion of reducing sugar range was 21% (g %) in un hydrolyzed green banana peels and maximum of 76% in red ripened banana as a substrate.

Prospects in Bioscience: Addressing the Issues, 2012

Presently actinomycetes from rice rhizosphere are screened for novel bioactive secondary metaboli... more Presently actinomycetes from rice rhizosphere are screened for novel bioactive secondary metabolites and for biocontrol potential against fungal plant pathogens. A total of 102 actinomycetes were isolated from rice rhizosphere soils collected from Tamil Nadu, India. All the isolates were screened against sheath blight pathogen Rhizoctonia solani by dual culture method with inhibition zone range from 0.6 to 3.0 cm. Among 102, 56 have shown the antagonistic activity against R. solani. Due to superior biocontrol activity against fungal pathogens over the other actinomycetes, an efficient strain VSMGT1014 was selected and identified as Streptomyces sp. based on the biochemical and atomic force microscope observation. The culture filtrate of Streptomyces sp. VSMGT1014 remarkably inhibited the mycelial growth and conidial and sclerotial germination of many fungal pathogens such as Macrophomina phaseolina, Fusarium oxysporum, Fusarium udum, and Alternaria alternata. The strain Streptomyces sp.VSMGT1014 produced five different compounds with Rf value ranges: 0.46, 0.51, 0.61, 0.85, and 0.89. Ethyl acetate extract of crude metabolite from VSMGT1014 significantly inhibited the mycelia growth of most of the fungal pathogens as well as sclerotial germination of R. solani.

World Journal of Microbiology and Biotechnology, 2014

A total of 132 actinomycetes was isolated from different rice rhizosphere soils of Tamil Nadu, In... more A total of 132 actinomycetes was isolated from different rice rhizosphere soils of Tamil Nadu, India, among which 57 showed antagonistic activity towards Rhizoctonia solani, which is sheath blight (ShB) pathogen of rice and other fungal pathogens such as Macrophomina phaseolina, Fusarium oxysporum, Fusarium udum and Alternaria alternata with a variable zone of inhibition. Potential actinomycete strain VSMGT1014 was identified as Streptomyces aurantiogriseus VSMGT1014 based on the morphological, physiological, biochemical and 16S rRNA sequence analysis. The strain VSMGT1014 produced lytic enzymes, secondary metabolites, siderophore, volatile substance and indole acetic acid. Crude metabolites of VSMGT1014 showed activity against R. solani at 5 µg ml(-1); however, the prominent inhibition zone was observed from 40 to 100 µg ml(-1). Reduced lesion heights observed in culture, cells-free filtrate, crude metabolites and carbendazim on challenge with pathogen in the detached leaf assay. The high content screening test clearly indicated denucleation of R. solani at 5 µg ml(-1) treatment of crude metabolite and carbendazim respectively. The results conclude that strain VSMGT1014 was found to be a potential candidate for the control of ShB of rice as a bio fungicide.

Bioorganic & Medicinal Chemistry Letters, 2014

BMC Infectious Diseases, 2014

Prospects in Bioscience: Addressing the Issues, 2012

ABSTRACT Abstract The study of root-associated bacteria and their antagonistic potential is impor... more ABSTRACT Abstract The study of root-associated bacteria and their antagonistic potential is important not only for understanding their ecological role in the rhizosphere and the interaction with plants but also for the suppression of soilborne plant pathogens. In this context, a total of 206 fluorescent pseudomonads (FPs) were isolated from rice rhizosphere from southern part of Tamil Nadu. Initially 113 isolates were found which were active against Rhizoctonia solani, of which 89 were strongly active against R. solani with zone of inhibition range from 10 to 32 mm. Production of lytic enzymes such as chitinase, cellulase, protease, amylase and pectinase was reported along with other characteristics including phosphate solubilisation and siderophore formation in 89 antagonistic fluorescent pseudomonads. Antagonistic fluorescent pseudomonads were also tested towards other fungal pathogens such as Macrophomina phaseolina, Fusarium oxysporum, Fusarium udum and Alternaria alternata. Among 89 the strain VSMKU-4046 has high antagonistic potential against R. solani. Strain VSMKU-4046 significantly controls sheath blight of rice compared to control using sclerotia of R. solani through detached leaf assay. The lesion length around the sclerotium was measured, and ShB severity was rated by the relative lesion height (RLH) method with the following formula:% RLH = 100 x Total height of lesions / Total leaf height. %RLH=100×totalheightoflesions/totalleafheight

Chinese Chemical Letters, 2014

An eco-friendly water mediated synthesis of 1,2,3-triazolyl-2-aminopyrimidine hybrids as highly p... more An eco-friendly water mediated synthesis of 1,2,3-triazolyl-2-aminopyrimidine hybrids as highly potent anti-bacterial agents

Chalcogenide Letters, Dec 1, 2012

In the area of nanotechnology, the development of techniques for the controlled synthesis of meta... more In the area of nanotechnology, the development of techniques for the controlled synthesis of metal nanoparticles of well-defined size, shape and composition is a big challenge. Metal nanoparticles and nanocomposites exhibit unique electronic, magnetic, catalytic and optical properties that are different from those of bulk metals. This could result in interesting new applications that could potentially be utilized in the biomedical sciences and areas such as optics and electronics [1]. Nanomaterials are at the leading edge of the rapidly developing ...

Springer Proceedings in Energy, 2020

The present investigation aims to produce an alternative fuel in the form of biofuels from cassav... more The present investigation aims to produce an alternative fuel in the form of biofuels from cassava and sweet potato by simultaneous saccharification and fermentation (SSF). Sweet potato and cassava are one of the richest sources of starch for production of bioethanol. The work highlights the novelty factor of coupled reaction stage in the production of bioethanol. Amylase-producing fluorescent pseudomonads was isolated, and the process parameters were optimized to get maximum ethanol yield. The dry matter ratio of cassava as well as sweet potato to water from 1:10 to 1:2 (w/v) was studied, respectively. Fresh raw materials were dried at 50 °C and assayed. At ratios of 1:6, similar results for both sources in terms of ethanol concentration (30–35 g/L), fermentation time (24 h) and complete sugar conversion were found. The results showed that sweet potato is a suitable source which showed significantly higher ethanol production yield.

e-Journal of Surface Science and Nanotechnology, 2015

The series Springer Proceedings in Energy covers a broad range of multidisciplinary subjects in t... more The series Springer Proceedings in Energy covers a broad range of multidisciplinary subjects in those research fields closely related to present and future forms of energy as a resource for human societies. Typically based on material presented at conferences, workshops and similar scientific meetings, volumes published in this series will constitute comprehensive state-of-the-art references on energy-related science and technology studies. The subjects of these conferences will fall typically within these broad categories:

The efficacy of a rhizobacteriumStreptomyces aurantiogriseusVSMGT1014 for the production of bioac... more The efficacy of a rhizobacteriumStreptomyces aurantiogriseusVSMGT1014 for the production of
bioactive metabolites with antifungal properties was evaluated underin vitro conditions. The
production of bioactive metabolites by S. aurantiogriseus VSMGT1014 in International
Streptomyces Project-2 (ISP-2) broth, supplemented with glucose and ammonium acetate was
found to be the most suitable carbon and nitrogen sources for the maximum production of
bioactive metabolites against rice pathogen,Rhizoctonia solani. The zone of inhibition range from
23.5 to 28.5mm and 10.3 to 18.3mm for glucose and ammonium acetate supplemented media,
respectively. The culturefiltrate of S. aurantiogriseusVSMGT1014 at pH 7.5, 37 °C at 120 rpm in
6 days of incubation showed the maximum productionof bioactive metaboliteswith antagonistic
potential. The crude metabolitewas characterizedby different spectral studies suchasUltraviolet
spectrum, infrared-spectrum and based on the different analytical techniques, including thin
layer chromatography (TLC) and high performance liquid chromatography (HPLC) with the
retention time 29.4 and the bioactive metabolite was identified as phenazine, which was
confirmed by pure phenazine compound as positive control.