Nidhi Joshi - Academia.edu (original) (raw)

Papers by Nidhi Joshi

Environmental Progress & Sustainable Energy

This study deals with the potential of bioflocculant for the treatment of various industrial wast... more This study deals with the potential of bioflocculant for the treatment of various industrial wastewaters. Bioflocculant (BFBl) produced by Bacillus licheniformis NJ3, showed 97% flocculating activity in primary screening (kaolin assay). The characteristics of the BFBl such as temperature and pH stability, cation-independency makes the flocculation process more economic as harmful coagulants and stabilizers are not required. BFBl efficiently treated synthetic wastewaters as compared to alum by reducing turbidity (69-87%), chemical oxygen demand (50-80%) and oil (87%). Further BFBl was used to treat pesticide, petroleum, pharmaceutical and starch processing industrial wastewaters having diversified pH. It reduced total suspended solids (61.9-80%), turbidity (54-94%), total dissolved solids (11-54%), oil and grease (75%) and heavy metals (62-100%) from wastewaters in the absence of cations without altering the temperature and pH. Additionally, Sludge settling process in the presence of BFBl was three times faster as compared to alum. Thus, BFBl successfully treats various wastewaters reducing multiple pollution indices. BFBl was a glycoprotein with 92% polysaccharide and 7% protein contents providing biodegradable nature. As a result, BFBl emerged as environment-friendly and economical alternative for the bioremediation of various industrial wastewaters.

Anal. Methods, 2016

1H NMR spectroscopy based metabolic analysis of ice stored Protonibea diacanthus tissue extracts ... more 1H NMR spectroscopy based metabolic analysis of ice stored Protonibea diacanthus tissue extracts points to the prospect of pyruvate becoming a probable marker for their quality assessment.

Aquatic Living Resources, 2015

The Gujarat government has proposed a project to convert a part of the Gulf of Khambhat (GoK), lo... more The Gujarat government has proposed a project to convert a part of the Gulf of Khambhat (GoK), located in western India, into the world's largest man-made freshwater reservoir in the near future (http://www.kalpasar.gujarat. gov.in/mainpage.htm). Anticipating the impact of the change on native bacterial communities, 145 bacteria were isolated initially from different parts of GoK, and further narrowed down to 12 on the basis of diversified geographic distribution in the GoK for further study. All the isolates were able to grow in the complete range of salinity tested (1% to 4%), however an influence of salinity on biofilm formation was observed in only a few isolates. Interestingly, two isolates (91 and 103) identified as Photobacterium damselae and Vibrio alginolyticus by MIDI and 16sr RNA sequencing were able to produce biofilm only at low salinity conditions (1% to 2%). Along with biofilm formation, isolate 103 showed higher virulence potential in an Artemia model only at lower salinity (1%). Therefore, isolate 103 was selected for further characterisation and the image of biofilm developed on a timescale basis (up to 24 h) for this isolate was studied using a scanning electron microscope (SEM). The change in biofilm surface morphology was studied by atomic-force microscopy (AFM). Live/dead bacterial composition of 24 hour-old matured biofilm also showed that the number of dead bacteria was higher than live bacteria. To the authors' best knowledge, this is the first study showing a change in virulence potential as well as biofilm formation by marine bacteria, exclusively under low salinity stress.

BioEnergy Research, 2012

The present study deals with the first systematic study on the isolation, characterization, and u... more The present study deals with the first systematic study on the isolation, characterization, and utilization of marine yeast for bioethanol production using seaweed biomass. The ability and efficiency of isolated marine yeast to grow and ferment sugar to ethanol in the presence of 2.5 % to 15 % salt concentration was validated by fermenting galactose in the presence of different salts at varied concentrations. Successively, this yeast was employed for fermentation of seaweed hydrolysate, containing high salt concentration, to ethanol. The hydrolysate having varying sugar as well as salt contents, from 2.7 % to 5.5 % and from 6.25 to 11.25 %, respectively, yielded 1.23-1.76 % ethanol. Through biochemical, fatty acid methyl ester analysis, and BioLog, the yeast was identified as Candida sp. The ability of this yeast to function at high salinity can be commercialized for its use to convert seaweed polysaccharide based hydrolysate, rich in salt, to ethanol without desalting process, ultimately making the process more efficient and economically viable. This is the first organized study for the utilization of marine yeast for converting Kappaphycus alvarezii, a red algal biomass, into ethanol as a byproduct, under highly saline condition.

Journal of Membrane Science, 2013

ABSTRACT The hitherto unreported 2,4,6-pyridinetricarboxylic acid chloride (PTC) was used with/wi... more ABSTRACT The hitherto unreported 2,4,6-pyridinetricarboxylic acid chloride (PTC) was used with/without trimesoyl chloride (TMC) in the interfacial polymerization reaction with meta-phenylene diamine (MPD) to produce a salt-rejecting polyamide coating over polysulphone support. Besides exhibiting higher reactivity towards MPD, the resultant thin film composite (TFC) membrane showed a lower tendency towards bacterial attachment in comparison to the membrane prepared with TMC alone. The best results were obtained with 2:3–1:1 M ratio of PTC to TMC, in as much as the flux was also enhanced and the salt rejection efficiency remained almost unaffected. The membranes were characterized by ATR-IR spectroscopy, elemental analysis, SEM, AFM, contact angle and zeta potential measurements.

International Journal of Biological Macromolecules, 2013

The potential of an alkaliphilic bacterium Klebsiella sp. strain RJ-03, to utilize different unco... more The potential of an alkaliphilic bacterium Klebsiella sp. strain RJ-03, to utilize different unconventional carbon sources for the production of biosurfactant was evaluated. The biosurfactant produced using corn powder, potato peel powder, Madhuca indica and sugarcane bagasse containing medium, exhibited significantly higher viscosity and maximum reduction in surface tension as compared to other substrates. Among several carbon substrates tested, production of biosurfactant was found to be the highest with corn powder (15.40 ± 0.21 g/l) as compared to others. The comparative chemical characterization of purified biosurfactant was done using advance analytical tools such as NMR, FT-IR, SEM, GPC, MALDI TOF-TOF MS, GC-MS, TG and DSC. Analyses indicated variation in the functional groups, monosaccharide composition, molecular mass, thermostability. Higher yield with cheaper raw materials, noteworthy stress tolerance of CP-biosurfactant toward pH and salt as well as compatibility with chemical surfactants and detergents revealed its potential for commercialization and application in bioremediation.

Environmental Progress & Sustainable Energy

This study deals with the potential of bioflocculant for the treatment of various industrial wast... more This study deals with the potential of bioflocculant for the treatment of various industrial wastewaters. Bioflocculant (BFBl) produced by Bacillus licheniformis NJ3, showed 97% flocculating activity in primary screening (kaolin assay). The characteristics of the BFBl such as temperature and pH stability, cation-independency makes the flocculation process more economic as harmful coagulants and stabilizers are not required. BFBl efficiently treated synthetic wastewaters as compared to alum by reducing turbidity (69-87%), chemical oxygen demand (50-80%) and oil (87%). Further BFBl was used to treat pesticide, petroleum, pharmaceutical and starch processing industrial wastewaters having diversified pH. It reduced total suspended solids (61.9-80%), turbidity (54-94%), total dissolved solids (11-54%), oil and grease (75%) and heavy metals (62-100%) from wastewaters in the absence of cations without altering the temperature and pH. Additionally, Sludge settling process in the presence of BFBl was three times faster as compared to alum. Thus, BFBl successfully treats various wastewaters reducing multiple pollution indices. BFBl was a glycoprotein with 92% polysaccharide and 7% protein contents providing biodegradable nature. As a result, BFBl emerged as environment-friendly and economical alternative for the bioremediation of various industrial wastewaters.

Anal. Methods, 2016

1H NMR spectroscopy based metabolic analysis of ice stored Protonibea diacanthus tissue extracts ... more 1H NMR spectroscopy based metabolic analysis of ice stored Protonibea diacanthus tissue extracts points to the prospect of pyruvate becoming a probable marker for their quality assessment.

Aquatic Living Resources, 2015

The Gujarat government has proposed a project to convert a part of the Gulf of Khambhat (GoK), lo... more The Gujarat government has proposed a project to convert a part of the Gulf of Khambhat (GoK), located in western India, into the world's largest man-made freshwater reservoir in the near future (http://www.kalpasar.gujarat. gov.in/mainpage.htm). Anticipating the impact of the change on native bacterial communities, 145 bacteria were isolated initially from different parts of GoK, and further narrowed down to 12 on the basis of diversified geographic distribution in the GoK for further study. All the isolates were able to grow in the complete range of salinity tested (1% to 4%), however an influence of salinity on biofilm formation was observed in only a few isolates. Interestingly, two isolates (91 and 103) identified as Photobacterium damselae and Vibrio alginolyticus by MIDI and 16sr RNA sequencing were able to produce biofilm only at low salinity conditions (1% to 2%). Along with biofilm formation, isolate 103 showed higher virulence potential in an Artemia model only at lower salinity (1%). Therefore, isolate 103 was selected for further characterisation and the image of biofilm developed on a timescale basis (up to 24 h) for this isolate was studied using a scanning electron microscope (SEM). The change in biofilm surface morphology was studied by atomic-force microscopy (AFM). Live/dead bacterial composition of 24 hour-old matured biofilm also showed that the number of dead bacteria was higher than live bacteria. To the authors' best knowledge, this is the first study showing a change in virulence potential as well as biofilm formation by marine bacteria, exclusively under low salinity stress.

BioEnergy Research, 2012

The present study deals with the first systematic study on the isolation, characterization, and u... more The present study deals with the first systematic study on the isolation, characterization, and utilization of marine yeast for bioethanol production using seaweed biomass. The ability and efficiency of isolated marine yeast to grow and ferment sugar to ethanol in the presence of 2.5 % to 15 % salt concentration was validated by fermenting galactose in the presence of different salts at varied concentrations. Successively, this yeast was employed for fermentation of seaweed hydrolysate, containing high salt concentration, to ethanol. The hydrolysate having varying sugar as well as salt contents, from 2.7 % to 5.5 % and from 6.25 to 11.25 %, respectively, yielded 1.23-1.76 % ethanol. Through biochemical, fatty acid methyl ester analysis, and BioLog, the yeast was identified as Candida sp. The ability of this yeast to function at high salinity can be commercialized for its use to convert seaweed polysaccharide based hydrolysate, rich in salt, to ethanol without desalting process, ultimately making the process more efficient and economically viable. This is the first organized study for the utilization of marine yeast for converting Kappaphycus alvarezii, a red algal biomass, into ethanol as a byproduct, under highly saline condition.

Journal of Membrane Science, 2013

ABSTRACT The hitherto unreported 2,4,6-pyridinetricarboxylic acid chloride (PTC) was used with/wi... more ABSTRACT The hitherto unreported 2,4,6-pyridinetricarboxylic acid chloride (PTC) was used with/without trimesoyl chloride (TMC) in the interfacial polymerization reaction with meta-phenylene diamine (MPD) to produce a salt-rejecting polyamide coating over polysulphone support. Besides exhibiting higher reactivity towards MPD, the resultant thin film composite (TFC) membrane showed a lower tendency towards bacterial attachment in comparison to the membrane prepared with TMC alone. The best results were obtained with 2:3–1:1 M ratio of PTC to TMC, in as much as the flux was also enhanced and the salt rejection efficiency remained almost unaffected. The membranes were characterized by ATR-IR spectroscopy, elemental analysis, SEM, AFM, contact angle and zeta potential measurements.

International Journal of Biological Macromolecules, 2013

The potential of an alkaliphilic bacterium Klebsiella sp. strain RJ-03, to utilize different unco... more The potential of an alkaliphilic bacterium Klebsiella sp. strain RJ-03, to utilize different unconventional carbon sources for the production of biosurfactant was evaluated. The biosurfactant produced using corn powder, potato peel powder, Madhuca indica and sugarcane bagasse containing medium, exhibited significantly higher viscosity and maximum reduction in surface tension as compared to other substrates. Among several carbon substrates tested, production of biosurfactant was found to be the highest with corn powder (15.40 ± 0.21 g/l) as compared to others. The comparative chemical characterization of purified biosurfactant was done using advance analytical tools such as NMR, FT-IR, SEM, GPC, MALDI TOF-TOF MS, GC-MS, TG and DSC. Analyses indicated variation in the functional groups, monosaccharide composition, molecular mass, thermostability. Higher yield with cheaper raw materials, noteworthy stress tolerance of CP-biosurfactant toward pH and salt as well as compatibility with chemical surfactants and detergents revealed its potential for commercialization and application in bioremediation.