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( Prakasham Reddy Shetty ),( Buddana Sudheer Kumar ),( Yannam Sudheer Kumar ),( Guntuku Girija Shankar ) 한국미생물 · 생명공학회 2012 Journal of microbiology and biotechnology Vol.22 No.5
Silver nanoparticles production by the green chemistry approach was investigated using an isolated marine actinomycetes strain. The isolated strain was identified as Streptomyces albidoflavus based on chemotaxonomic and ribotyping properties. The strain revealed production of silver nanoparticles both extracellular and intracellularly. Surface Plasmon Resonance analysis with the function of time revealed that particle synthesis by this strain is reaction time dependent. The produced particles were spherical shaped and monodispersive in nature and showed a single surface plasmon resonance peak at 410 nm. Size distribution histograms indicated production of 10-40- nm-size nanoparticles with a mean size of 14.5 nm. FT-IR spectra of nanopartilces showed N-H, C-H, and C-N stretching vibrations, denoting the presence of amino acid/ peptide compounds on the surface of silver nanoparticles produced by S. albidoflavus. Synthesized nanoparticles revealed a mean negative zeta potential and electrophoretic mobility of -8.5 mV and -0.000066 cm2/Vs, respectively. The nanoparticles produced were proteinaceous compounds as capping agents with -8.5 mV zeta potential and revealed antimicrobial activity against both Gram-negative and -positive bacterial strains. Owing to their small size, these particles have greater impact on industrial application spectra.
Rao Ravella Sreenivas,Jyothi Cherukuri Pavanna,Prakasham Reddy Shetty,Rao Chaganti Subba,Sarma Ponnupalli Nageshwara,Rao Linga Venkateswar The Microbiological Society of Korea 2006 The journal of microbiology Vol.44 No.1
Candida tropicalis was treated with ultraviolet (UV) rays, and the mutants obtained were screened for xylitol production. One of the mutants, the UV1 produced 0.81g of xylitol per gram of xylose. This was further mutated with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), and the mutants obtained were screened for xylitol production. One of the mutants (CT-OMV5) produced 0.85g/g of xylitol from xylose. Xylitol production improved to 0.87 g/g of xylose with this strain when the production medium was supplemented with urea. The CT-OMV5 mutant strain differs by 12 tests when compared to the wild-type Candida tropicalis strain. The XR activity was higher in mutant CT-OMV5. The distinct difference between the mutant and wild-type strain is the presence of numerous chlamvdospores in the mutant. In this investigation, we have demonstrated that mutagenesis was successful in generating a superior xylitol-producing strain, CT-OMV5, and uncovered distinctive biochemical and physiological characteristics of the wild-type and mutant strain, CT-OMV5.
Biosynthesis of Xylobiose: A Strategic Way to Enrich the Value of Oil Palm Empty Fruit Bunch Fiber
( Lakshmi G ),( Suvarna B ),( Uma Rejeswari ),( R S Prakasham ) 한국미생물 · 생명공학회 2012 Journal of microbiology and biotechnology Vol.22 No.8
Xylooligosaccharides are functional foods mainly produced during the hydrolysis of xylan by physical, chemical, or enzymatic methods. In this study, production of xylobiose was investigated using oil palm empty fruit bunch fiber (OPEFB) as a source material, by chemical and enzymatic methods. Xylanase-specific xylan hydrolysis followed by xylobiose production was observed. Among different xylanases, xylanase from FXY-1 released maximum xylobiose from pretreated OPEFB fiber, and this fungal strain was identified as Aspergillus terreus and subsequently deposited under the accession Number MTCC- 8661. The imperative role of lignin on xylooligosaccharides enzymatic synthesis was exemplified with the notice of xylobiose production only with delignified material. A maximum 262 mg of xylobiose was produced from 1.0 g of pretreated OPEFB fiber using FXY-1 xylanase (6,200 U/ml) at pH 6.0 and 45oC. At optimized environment, the yield of xylobiose was improved to 78.67 g/100 g (based on xylan in the pretreated OPEFB fiber).
Linga Venkateswar Rao,Cherukuri Pavana Jyothi,Reddy Shetty Prakasham,Chaganti Subba Rao,Ponnupalli Nageshwara Sarma,Ravella Sreenivas Rao 한국미생물학회 2006 The journal of microbiology Vol.44 No.1
Candida tropicalis was treated with ultraviolet (UV) rays, and the mutants obtained were screened for xylitol production. One of the mutants, the UV1 produced 0.81g of xylitol per gram of xylose. This was further mutated with N-methyl-N’-nitro-N-nitrosoguanidine (MNNG), and the mutants obtained were screened for xylitol production. One of the mutants (CT-OMV5) produced 0.85g/g of xylitol from xylose. Xylitol production improved to 0.87 g/g of xylose with this strain when the production medium was supplemented with urea. The CT-OMV5 mutant strain differs by 12 tests when compared to the wild-type Candida tropicalis strain. The XR activity was higher in mutant CT-OMV5. The distinct difference between the mutant and wild-type strain is the presence of numerous chlamydospores in the mutant. In this investigation, we have demonstrated that mutagenesis was successful in generating a superior xylitol-producing strain, CT-OMV5, and uncovered distinctive biochemical and physiological characteristics of the wild-type and mutant strain, CT-OMV5.
Laccase- and Peroxidase-Free Tyrosinase Production by Isolated Microbial Strain
( Sambasiva Rao K. R. S. ),( N. K. Tripathy ),( Y. Mahalaxmi ),( R. S. Prakasham ) 한국미생물 · 생명공학회 2012 Journal of microbiology and biotechnology Vol.22 No.2
Laccase- and peroxidase-free tyrosinase has commercial importance in the production of L-3, 4-dihydroxyphenylalanine (L-DOPA), which is mainly used in the treatment of Parkinson`s disease. In the present study, isolation of an actinomycetes microbial strain capable of producing only tyrosinase is reported. Among all soil isolates, three individual colonies revealed black color around the colony in the presence of tyrosine. Further screening for laccase and peroxidase activities using syringaldazine denoted that one of the isolates, designated as RSP-T1, is laccase and peroxidase negative and produces only tyrosinase. The microbe was authenticated as Streptomyces antibioticus based on 16S ribotyping. Effective growth of this isolate was noticed with the use of medium (pH 5.5) containing casein acid hydrolysate (10.0 g/l), K2HPO4 (5.0 g/l), MgSO4 (0.25 g/l), L-tyrosine (1.0 g/l), and agar (15 g/l). The scanning electron micrograph depicted that the microbe is highly branched and filamentous in nature. The enzyme production was positively regulated in the presence of copper sulfate. The impact of different fermentation parameters on tyrosinase production depicted that the maximized enzyme titer values were observed when this isolate was grown at 6.5 pH and at 30oC temperature under agitated conditions (220 rpm). Among all the studied physiological parameters, agitation played a significant role on tyrosinase production. Upon optimization of the parameters, the yield of tyrosinase was improved more than 100% compared with the initial yield.