Isolation and Identification of Lipolytic Enzyme Producing Pseudomonas sp. OME and Optimization of Cultural Conditions

G. Satheesh kumar,T. Kiran Reddy,B. Madhavi,P. Charan Teja,M. Subhosh Chandra,Yong Lark Choi 한국생명과학회 2010 생명과학회지 Vol.20 No.5

폐식용유에서 지방분해효소를 생산하는 세균을 분리하였고, PIBWIN 세균동정 방법으로 생리 생화학적 특성을 조사하여 확인한 결과 Pseudomonas sp. OME로 동정하였다. 여러 기질로 지방분해효소 생산을 조사한 결과 올리브유에서 6.1 U/㎖의 생산력을 나타내었다. 물리적 인자인 배양시간, 온도. pH 및 올리브유와 효모 추출액의 영양인자에 의한 지방분해효소 생산 조건을 조사 하였다. 효소의 분비는 배양시간. 올리브유 와 효모 추출액의 농도에 강한 영향을 받았으며, RSM을 이용한 최적화는 이들 인자를 가지고 조사하였다. RSM을 이용한 지방분해효소 생산은 배양시간. 올리브유와 효모 추출액의 농도가 48 hr, 0.3 g, 및 0.9 ㎖에서 최적 생산조건을 나타냈다. Lipolytic enzyme-producing bacteria were isolated from edible oil mill effluents on tributyrin agar medium. The shake-flask-scale studies yielded a promising isolate and it was identified as Pseudomonas sp. An OME using various microbiological observations such as cultural, microscopic, and biochemical tests was undertaken and confirmed using PIBWIN bacterial identification software. Lipolytic enzyme production was screened with oils such as sunflower, caster, coconut, tributyrin, and olive. Amongst these, olive oil showed an increased lipase production 6.1 U/㎖. In view of the highest lipolytic enzyme production with olive oil, further optimizations were carried out using olive oil as a carbon source. Lipolytic enzyme production was optimized by a conventional ‘one variable at a time’ approach and the significant factors were further analyzed statistically using response surface methodology (RSM). The effect of physical factors such as incubation time, temperature, initial medium pH, and nutritional factors such as concentration of olive oil and yeast extract were examined for lipase production. Lipolytic enzyme secretion was strongly affected by three variables (incubation time, concentration of yeast extract and olive oil). Therefore, the interaction of these three factors was further optimized using response surface methodology. The optimized conditions of lipase production using response surface methodology yielded a maximum of 9.62 U/㎖ with optimum conditions for incubation, yeast extract and olive oil concentrations were found to be 48 hr, 0.3 g. and 0.9 ㎖. respectively.

Design of geocell reinforcement for supporting embankments on soft ground

Latha, G. Madhavi Techno-Press 2011 Geomechanics & engineering Vol.3 No.2

The methods of design available for geocell-supported embankments are very few. Two of the earlier methods are considered in this paper and a third method is proposed and compared with them. In the first method called slip line method, plastic bearing failure of the soil was assumed and the additional resistance due to geocell layer is calculated using a non-symmetric slip line field in the soft foundation soil. In the second method based on slope stability analysis, general-purpose slope stability program was used to design the geocell mattress of required strength for embankment. In the third method proposed in this paper, geocell reinforcement is designed based on the plane strain finite element analysis of embankments. The geocell layer is modelled as an equivalent composite layer with modified strength and stiffness values. The strength and dimensions of geocell layer is estimated for the required bearing capacity or permissible deformations. These three design methods are compared through a design example. It is observed that the design method based on finite element simulations is most comprehensive because it addresses the issue of permissible deformations and also gives complete stress, deformation and strain behaviour of the embankment under given loading conditions.

Taming of large diameter triaxial setup

Nair, Asha M.,Madhavi Latha, G. Techno-Press 2012 Geomechanics & engineering Vol.4 No.4

Triaxial tests are essential to estimate the shear strength properties of the soil or rock. Normally triaxial tests are carried out on samples of 38 mm diameter and 76 mm height. Granular materials, predominantly used in base/sub-base construction of pavements or in railways have size range of 60-75 mm. Determination of shear strength parameters of those materials can be made possible only through triaxial tests on large diameter samples. This paper describes a large diameter cyclic triaxial testing facility set up in the Geotechnical Engineering lab of Indian Institute of Science. This setup consists of 100 kN capacity dynamic loading frame, which facilitates testing of samples of up to 300 mm diameter and 600 mm height. The loading ram can be actuated up to a maximum frequency of 10 Hz, with maximum amplitude of 100 mm. The setup is capable of carrying out static as well as dynamic triaxial tests under isotropic, anisotropic conditions with a maximum confining pressure of 1 MPa. Working with this setup is a difficult task because of the size of the sample. In this paper, a detailed discussion on the various problems encountered during the initial testing using the equipment, the ideas and solutions adopted to solve them are presented. Pilot experiments on granular sub-base material of 53 mm down size are also presented.

Simple synthesis of biogenic PdAg bimetallic nanostructures for an ultra-sensitive electrochemical sensor for sensitive determination of uric acid

Mallikarjuna, K.,Veera Manohara Reddy, Y.,Sravani, Bathinapatla,Madhavi, G.,Kim, Haekyoung,Agarwal, Shilpi,Gupta, Vinod Kumar Elsevier 2018 Journal of Electroanalytical Chemistry Vol.822 No.-

<P><B>Abstract</B></P> <P>Bimetallic nanomaterials have potential catalytic behaviour in hydrogenation, clean- energy production, catalysis and sensors due to their great stability, loftier activity unique electrical and chemical properties. Herein, we prepared PdAg bimetallic nanoparticles synthesized by using fungal extracted aqueous method, which is environmentally friendly cost-effective and simple procedure. The fabricated PdAg bimetallic nanoparticles were investigated by small area electron diffraction (SAED), transmission electron microscopy (TEM) X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX) analysis. The electrochemical response of uric acid (UA) at Pd-Ag/CPE was studied in 0.1 M phosphate buffer solution at various pH, concentration and scan rate was investigated. Compare to Bare CPE, the PdAg nanocomposite modified electrode displayed the highest electrocatalytic activity for the detection of UA A linear response in the range of 4.69–273 nM with remarkable detection limit of 5.543 nM (C<SUB>DL</SUB> = 3ϭ/M) and quantification limit of 16.64 nM (C<SUB>QL</SUB> = 10ϭ/M) was obtained. The established nanoparticles (PdAg) embedded with carbon paste electrode (Pd-Ag/CPE) makes a good analytical tool for the sensing of UA in the biological and pharmaceutical samples.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Pd-Ag bimetallic nanoparticles based electrochemical sensor was fabricated </LI> <LI> uric acid is determined at nanomolar levels </LI> <LI> The practical feasibility of the developed sensor was successfully was performed </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Electrochemical investigation of uric acid at biogenic PdAg bimetallic nanostructures modified carbon paste electrode.</P> <P>[DISPLAY OMISSION]</P>

Facile Preparation of Ionic Liquid-coated Copper Nanowire-modified Carbon Paste Electrode for Electrochemical Detection of Etilefrine Drug

Sada Venkateswarlu,Manthrapudi Venu,Yenegu Veera Manohara Reddy,Bathinapatla Sravani,코두루말리카주나,윤민영,G. Madhavi 대한화학회 2019 Bulletin of the Korean Chemical Society Vol.40 No.6

A carbon paste electrode (CPE)/Cu nanowire (Cu NW)/poly(1-ethyl-3-methylimidazolium methyl sulfate) based sensor was successfully fabricated by the electro-polymerization of 1-ethyl-3-methylimidazolium methyl sulfate (EMIMS) onto the surface of Cu nanowires-modified carbon paste electrode. The morphology and chemical nature of Cu NWs were characterized by FTIR, FE-SEM, TEM, XRD techniques. The CPE/CuNWs/poly(EMIMS) showed an electrocatalytic activity toward the determination of etilefrine hydrochloride (ET-HCl) in the 0.11?M buffer solution of phosphate at pH 7.0. The CPE/CuNWs/poly(EMIMS) showed an excellent limit of detection (LOD) 2.3 ?M over the linear dynamic range of 0.1 to 1.3 ?M. The prepared CPE/CuNWs/poly(EMIMS) has exhibited high stability, good sensitivity, and low detection limit for the determination of ET-HCl. The validity of this advanced method was checked by applying in the blood plasma samples, with satisfactory results. This novel CPE/CuNWs/poly(EMIMS) can be an attractive material for the applications in biomedical and sensor fields.

Effect of Sulfamerazine on Structural Characteristics of Sodium Alginate Biopolymeric Films

Yerramathi Babu Bhagath,이소연,Manjula Kola,TATA SANJAY KANNA SHARMA,Annem Muniraj Beulah,Y. Veera Manohara Reddy,박태정,박종필,Ravi Sahukari,G. Madhavi 한국생물공학회 2022 Biotechnology and Bioprocess Engineering Vol.27 No.4

The present study was intended to describe and understand the mechanical, structural, morphological, and antimicrobial properties of sodium alginate (SA) biopolymeric films doped with sulfamerazine (SMR). Tensile strength (TS), elongation at break (E%), intermolecular interactions, crystallinity, structural integrity, and surface properties were investigated for SMR concentrations of 0.6, 1.2, and 1.8 mg/mL in the film-forming solution. The TS and E% of the various experimental films differed significantly according to the SMR concentration (p < 0.05). However, a slight reduction was observed at the highest SMR concentration (1.8 mg/mL). Fourier transform infrared spectroscopy and X-ray diffraction patterns revealed the reaction of the functional groups and conformational changes caused by the SMR and Ca2+ ions in the film matrix. Scanning electron microscopy and atomic force microscopy image analysis illustrated the cross-sectional microstructure and surface roughness of the experimental films. Overall, the doping of SMR into the SA polymer matrix was proven to have a significant effect on the morphological, structural, and mechanical properties of the resulting films.