Anuradha Nerurkar

The Maharaja Sayajirao University of Baroda | MSU

Biological denitrification is the most promising alternative approach for the removal of nitrate from wastewater. MBBR inoculated with activated sludge is a widely studied approach, but very few studies have focused on the bioaugmentation of biofilm forming bacteria in MBBR. Our study revealed that the use of special microbial seed of biofilm formi...

AimsThe aim of this study was to isolate soilborne AHL degrading actinobacteria that can be used as biocontrol agents against the quorum sensing mediated virulence of Pectobacterium carotovorum subsp. carotovorum BR1 in in vitro and in planta studies.Methods Actinobacterial strains capable of N-acyl homoserine lactone (AHL) degradation, Glutamiciba...

The sugar-yield, after deconstruction and saccharification of lignocellulosic biomass, is the outcome of the efficiency of pretreatments applied and accessibility of biomass to the formulated tailor-made enzyme cocktail of plant cell wall degrading enzymes amended in the process. Different chemicals, used during the pretreatments of sugarcane bagas...

Application of crude xylanolytic and pectinolytic enzymes in diverse industrial processes make these enzymes commercially valuable and demand their production process to be cost-effective. Out of four different agrowaste biomass, wheat bran (WB) and citrus peel (CP), when amended as fermentation substrates, respectively induced the highest xylanoly...

Restricted activities of individual plant cell wall–degrading enzymes, i.e., cellulase, xylanase, and pectinase, on plant biomass are due to the complex interactions among structural polysaccharides and lignin components of plant cell wall. This can be overcome through altering the structural components by subjecting biomass to physicochemical pret...

Bacillus cereus CR4 from the flocs of activated sludge was found to produce an extracellular bioflocculant, which was characterized as amyloid protein and demonstrated to have potential application in microalgae recovery. Cell surface amyloid production was demonstrated by fluorescence, confocal and scanning electron microscopy. Birefringence, spec...

After chemical pretreatment, improved amenability of agrowaste biomass for enzymatic saccharification needs an understanding of the effect exerted by pretreatments on biomass for enzymatic deconstruction. In present studies, NaOH, NH4OH and H2SO4 pretreatments effectively changed visible morphology imparting distinct fibrous appearance to sugarcane...

Considering the importance of methylotrophs in industrial wastewater treatment, focus of the present study was on utilization of a methylotrophic bacterial consortium as a microbial seed for biotreatment of a variety of industrial effluents. For this purpose, a mixed bacterial methylotrophic AC (Ankleshwar CETP) consortium comprising of Bordetella...

Quorum sensing is a process of cell-cell communication by which the bacteria vary their gene expression mediated by a self-produced signalling molecule in a population density dependent manner to coordinate their behaviour which is virulence in phytopathogens. Quorum quenching or quorum sensing inhibition is a broad term used to include many divers...

Quorum sensing is a process of cell-cell communication by which the bacteria vary their gene expression mediated by a self-produced signalling molecule in a population density dependent manner to coordinate their behaviour which is virulence in phytopathogens. Quorum quenching or quorum sensing inhibition is a broad term used to include many divers...

Solibacillus silvestris AM1 was the first strain from the genus to be reported for the production of a functional amyloid and its potential use as a surface active agent, a thermostable glycoprotein amyloid bioemulsifier BE-AM1 capable of influencing environment and biofilm formation. Phylogenetic analysis based on 16S rRNA gene, molecular characte...

Aim: The aim of this study was to evaluate the physico-chemical properties of the crude pectinase activity from three Bacillus isolates of ruminant dung origin and study their synergism with crude xylanases from the same Bacillus spp. as well as a commercial cellulase to evaluate their accessory role in improved biomass saccharification. Methods...

With the increase in world population, the demand of fossil fuels has increased rapidly. With the rising concern of limited availability of the fossil fuels, the demand of alternative fuels like biodiesel has attained a considerable attention over a decade. Microalgae have shown to be one of the promising sources for the production of biodiesel, as...

Degradation of different chain length AHLs by Lysinibacillus sp. Gs50 and E.coli BL21(DE3) pET22b(+)/adeH. A (1, 2, 3) Lysinibacillus sp. Gs50+C4HSL, B (1, 2, 3) E.coli BL21(DE3)pET22b(+)/adeH +C4HSL, C (1, 2, 3) C4HSL+ C. violaceum CV026, D (1, 2, 3) Lysinibacillus sp. Gs50+C6HSL, E (1, 2, 3) E.coli BL21(DE3)pET22b(+)/adeH +C6HSL, F (1, 2, 3) C6HS...

AHL degradation kinetics of AdeH according to Michaelis-Menten equation at 35°C and pH 8.0. (TIF)

Lysis of Lysinibacillus sp. Gs50 cells after sonication. Microscopic images of before sonication and after sonication samples stained with (i) Crystal violet and (ii) Combination of trypan blue and nigrosin stains. (TIF)

Quantification of C6HSL using agar slice method. In sterile Luria agar (LA) plates, agar was aseptically cut into separated bars of 1cm width by removing 2 to 3 mm slices of agar between the bars. In the agar bars 3mm diameter wells were made. Overnight grown C. violaceum CV026 was streaked below each well. 6μl of C6HSL (60, 120, 180, 240, 300, 600...

Effect of pH on AdeH activity. C6HSL depicts the only substrate at different pH and AdeH + C6HSL depicts enzyme substrate reaction at different pH. (TIF)

Pectobacterium carotovorum subsp. carotovorum (Pcc) is an important broad host range, soft rot causing phytopathogen with multiple modes of infection. AHL mediated quorum sensing mechanism plays a pivotal role in pathogenesis of Pcc, by regulating its major virulence enzymes that degrade plant cell wall. Here, the disruption of quorum sensing as a...

Bacillus licheniformis TT42 produced a low-molecular weight anionic biosurfactant that reduced the surface tension of water from 72 to 27 mN/m and the interfacial tension from 12 to 0.05 mN/m against crude oil. We have earlier reported significant enhancement in oil recovery in laboratory sand pack columns and core flood studies, by biosurfactant-T...

A novel estuarine bacterial strain, Solibacillus silvestris AM1 produces extracellular, thermostable and fibrous, glycoprotein bioemulsifier AM1 (BE-AM1). The amyloid nature of bioemulsifier (BE-AM1) was confirmed by biophysical techniques (Congored based polarization microscopy; ThioflavinS based fluorescent microscopy, fibrous arrangement in tran...

Isolates were obtained from intertidal zone site samples from all five western and one eastern coastal states of India and were screened. These ecophysiological groups of aerobic, mesophilic, heterotrophic, sporulating, and bioemulsifier-producing bacteria were from Planococcaceae and Bacillaceae. This is the first report of bioemulsifier productio...

The final sugar yield in the first step of biofuel production from lignocellulosic biomass is determined by the extent of its saccharification by mixture of polysaccharide deconstructing enzymes. A combined action of enzymes comprising "Core enzymes” like cellulases and "Accessory enzymes" like xylanases, pectinases etc. accomplish this. Our aim wa...

There is a requirement to reduce nitrate in effluent. A Bacterial Consortia is required for this process. Carbon sources are required for its development. In this study, three denitrifying bacterial consortia were enriched using Winogradsky columns spiked with different carbon sources viz. acetate, methanol and fusel oil (mixture of alcohols-a by-p...

Plant biomass saccharification is the process where structural polysaccharides of plant materials are chemically or enzymatically broken down to oligosaccharide and/or monosaccharides. The enzymatic saccharification of cellulosic polysaccharides, engrossed in a complex matrix with hemicelluloses, necessitates involvement of variety of enzymes like...

Biofuel production is a two-step process containing (i) bioconversion of lignocellulosic biomass to sugars and (ii) their fermentation to alcohols. The bioconversion step is the saccharification mediated by mixture of polysaccharide hydrolases that determine the final fermentable sugar yield. The combined action of different “Core enzymes” like end...

Background: Turf soil bacterial isolate Delftia sp. VM4 can degrade exogenous N-acyl homoserine lactone (AHL), hence it effectively attenuates the virulence of bacterial soft rot pathogen Pectobacterium carotovorum subsp. carotovorum strain BR1 (Pcc BR1) as a consequence of quorum sensing inhibition. Methodology/principal findings: Isolated Delf...

Conditions required to enhance a particular species efficient in degradative capabilities is very useful in wastewater treatment processes. Paracoccus sp. is known to efficiently reduce nitrogen oxides (NOx) due to the branched denitrification pathway. Individual-based simulations showed that the relative fitness of Paracoccus sp. to Pseudomonas sp...

Polysaccharide hydrolase producing bacteria were isolated for biomass saccharification step in two-step bioethanol production. Xylanolytic bacteria were found to be common in ruminant dung. Seven Bacillus dung isolates exhibited high xylanolytic activity; three of which were identified as B. safensis and four as B. altitudinis, based on 16S rDNA an...

Microorganisms produce various types of extracellular polymers. One group of such polymers with surface active properties is referred to as bioemulsifiers, which are amphipathic molecules that stabilize oil-in-water emulsions. They belong to the category of high molecular weight biosurfactants and are known to increase surface area and bioavailabil...

Cellulose, xylan and pectin are structural polysaccharides, present in majority of plants. Ruminants feed upon plant based food material i.e. grass, leaf litter or agricultural roughage, by initially softening them in their well partitioned stomach, where microorganisms predominantly bacteria and fungi, produce diverse polysaccharide hydrolyzing en...

Coexistence of an autotrophic ammonia-oxidizing bacterium (Nitrosomonas sp. RA) and heterotrophic bacteria was consistently observed when cultured in an inorganic medium without any external supply of organic carbon. The present study was undertaken to understand the association between autotrophs and the associated heterotrophs for which a system...

There are many hypotheses for the natural roles of amphiphilic high molecular weight biosurfactants called as Bioemulsifiers. There have been no direct evidences for the bioemulsifier function as surface modulator. Solibacillus silvestris AM1, an estuarine isolate produces a potent thermo-resistant glycoprotein bioemulsifier AM1. The effects of bio...

Twenty different strains of Pectobacterium carotovorum (Pcc) were recovered from vegetable-growing fields of Vadodara, Gujarat (India) using a plant host enrichment approach during the years 2006–9. The isolated strains, based on differences in physiological and biochemical features, were classified into five different biovars, and then identified...

Diversity among biosurfactant producing Bacillus spp. from diverse habitats was studied among 77 isolates. Cluster analysis based on phenotypic characteristics using unweighted pair-group method with arithmetic averages (UPGMAs) method was performed. Bacillus isolates possessing high surface tension activity and five reference strains were subjecte...

A simultaneous partial nitrification, anammox and denitrification (SNAD) process was developed for the treatment of ammonia laden effluent of a fertilizer industry. Autotrophic aerobic and anaerobic ammonia oxidizing biomass was enriched and their ammonia removal ability was confirmed in synthetic effluent system. Seed consortium developed from the...

Bioemulsifiers (BE) are high molecular weight biosurfactants (BS) having amphipathic nature with hydrophobic and hydrophilic components. Wide structural variation in number of microbial emulsifier have been identified . It is becoming clear that bioemulsifiers may have various roles, some of which are unique to the physiology and ecology of the pro...

Diversity among biosurfactant producing Bacillus spp. from diverse habitats was studied among 77 isolates. Cluster analysis based on phenotypic characteristics using unweighted pair-group method with arithmetic averages (UPGMAs) method was performed. Bacillus isolates possessing high surface tension activity and five reference strains were subjecte...

An extracellular pectate lyase (PL, EC 4.2.2.2) produced by Pectobacterium carotovorum subsp. carotovorum BR1 was purified and characterized with respect to its biochemical properties including the thermodynamic parameters of substrates hydrolysis and thermal behavior. The PL showed higher affinity for polygalacturonic acid (Km, 0.4 g l−1) as compa...

Conventional primary and secondary oil recovery processes recover only one third of the oil present in the oil reservoir. EOR technologies produce an additional oil recovery after these processes cease to produce oil. Microbial enhanced oil recovery (MEOR) includes the tertiary oil recovery process where microorganisms or their metabolites are used...

Group of polymers, referred to as Bioemulsifiers, are amphipathic proteins and/or polysaccharides that stabilize oil-in-water emulsions. Solibacillus silvestris AM1, isolated from Chandra Canal estuarine sediment, Perangipette, TN, produces a potential bioemulsifier stabilizing emulsions with hydrocarbons. The interaction between microbe-biosurfact...

Bioemulsifiers are high molecular weight compounds that produce stable emulsions which allow bacteria to adhere strongly to hydrophobic surfaces and degrade large biological complexes. Solibacillus silvestris AM1, Gram positive, spore bearing bacterium which produces bioemulsifier when grown in Zobell Marine medium . In order to study the genetic b...

The abundance and structure of denitrifying bacterial community in different activated sludge samples were assessed, where the abundance of denitrifying functional genes showed nirS in the range of 10(4)-10(5), nosZ with 10(4)-10(6) and 16S rRNA gene in the range 10(9)-10(10) copy number per ml of sludge. The culturable approach revealed Pseudomona...

Denitrification was compared between Paracoccus sp. and Diaphorobacter sp. in this study, both of which were isolated from activated sludge of a denitrifying reactor. Denitrification of both isolates showed contrasting patterns, where Diaphorobacter sp. showed accumulation of nitrite in the medium while Paracoccus sp. showed no accumulation. The ni...

High molecular weight biosurfactants referred to as bioemulsifiers, are polymers which are shed into surrounding medium during the growth by the producing strains. Bioemulsifier produced by isolate Solibacillus silvestris sp.AM1 (GeneBank accession No. GU226320) obtained from marine sediment was studied for its physical and chemical characterizatio...

With emphasis on thermal behavior in presence of different pH conditions and salts, the kinetic and thermodynamic parameters of purified polygalacturonase (PG) of E. carotovora subsp. carotovora (Ecc) BR1 were studied since characterization of an enzyme is significant in the context of burgeoning biotechnological applications. Thermodynamic paramet...

Bacterial biofilms adapt and shape their structure in response to varied environmental conditions. A statistical methodology was adopted in this study to empirically investigate the influence of nutrients on biofilm structural parameters deduced from confocal scanning laser microscope images of Paracoccus sp.W1b, a denitrifying bacterium. High conc...

Lichenysins are most potent anionic cyclic lipoheptapeptide biosurfactants produced by Bacillus licheniformis on hydrocarbonless medium with mainly glucose as carbon source. They have the capacity to lower the surface tension of water from 72 to 27 mN/m. Based on species specific variations they are named lichenysin A, B, C, D, G and surfactant BL8...

Lichenysins are most potent anionic cyclic lipoheptapeptide biosurfactants produced by Bacillus licheniformis on hydrocarbonless medium with mainly glucose as carbon source. They have the capacity to lower the surface tension of water from 72 to 27 mN/m. Based on species specific variations they are named lichenysin A, B, C, D, G and surfactant BL8...

The selective plugging strategy of microbial enhanced oil recovery involves the use of microbes that grow and produce exopolymeric substances, which block the high permeability zones of an oil reservoir, thus allowing the water to flow through the low permeability zones leading to increase in oil recovery. Bacillus licheniformis TT33, a hot water s...

This review highlights bioemulsifier-producing marine microorganisms, which are capable of producing unique metabolites having industrial applications. High molecular weight biosurfactants (bioemulsifiers) produce stable emulsions, which allow bacteria to adhere strongly to hydrophobic surfaces and then degrade large biological complexes. Bioemulsi...

Halophilic archaea belonging to three different genera- Halobacterium, Haloarcula and Haloferax, were isolated from Kandla salt pans. The isolates had an optimum requirement of 25% NaCl for growth. Increase in organic solvent tolerance of isolates was observed at higher NaCl concentrations. Among the three isolates Halobacterium sp. SP1(1) was foun...

Bacillus licheniformis K125, isolated from an oil reservoir, produces an effective bioemulsifier. The crude bioemulsifier showed 66% emulsification activity (E(24)) and reduced the surface tension of water from 72 to 34 mN/m. It contains substantial amount of polysaccharide, protein and lipid. This bioemulsifier is pseudoplastic non-Newtonian in na...

Biosurfactant production was studied by Bacillus licheniformis K51, B. subtilis 20B, B. subtilis R1 and Bacillus strain HS3 using molasses or cheese whey as a sole source of nutrition at 45 degrees C. The isolates were able to grow and produce biosurfactant under shaking as well as static conditions. Maximum biosurfactant production was achieved wi...

The nutritional medium requirement for biosurfactant production by Bacillus licheniformis K51 was optimized. The important medium components, identified by the initial screening method of Plackett-Burman, were H3PO4, CaCl2, H3BO3, and Na-EDTA. Box-Behnken response surface methodology was applied to further optimize biosurfactant production. The opt...

Alcaligenes faecalis kw-A selected for possessing good denitrification efficiency was used for biofilm development. The biofilm could be developed on a glass surface within 12 hr when 5%, Ix 10(8) cells/ml was used as inoculum. The microcolonies were seen in 6 hr and glycocalyx in 9 hr stage. At 24 hr the biofilm was developed fully and hence was v...

Of the 29 potentially denitrifying organisms isolated from a denitrifying reactor (DNR) of a fertilizer company, two isolates; I-4 and I-5 were recognized as denitrifiers. Under aerobic conditions, with fusel oil as the carbon source, the organisms decreased nitrate from 1200 mg l–1 to 100 mg l–1 in 48 h. Optimal growth conditions for biological re...