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ABSTRACT: Aspergillus unguis NII-08123, a filamentous fungus isolated from soil, was found to produce β-glucosidase (BGL) activity with high glucose tolerance. Cultivation of the fungus in different carbon sources resulted in the secretion of different isoforms of the enzyme. A low molecular weight isoform, which retained ~60 % activity in the presence of 1.5 M glucose, was purified to homogeneity and the purified enzyme exhibited a temperature and pH optima of 60 °C and 6, respectively. The K m and V max of the enzyme were 4.85 mM and 2.95 U/mg, respectively, for 4-nitrophenyl β-D-glucopyranoside. The glucose inhibition constant of the enzyme was 0.8 M, indicating high glucose tolerance, and this is the second-highest glucose tolerance ever reported from the Aspergillus nidulans group. The glucose-tolerant BGL from A. unguis, when supplemented to cellulase preparation from Penicillium, could improve biomass hydrolysis efficiency by 20 % in 12 h compared to the enzyme without additional beta glucosidase supplementation. The beta glucosidase from A. unguis is proposed as a highly potent "blend-in" for biomass saccharifying enzyme preparations.
Journal of Industrial Microbiology and Biotechnology 06/2013; · 2.73 Impact Factor
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ABSTRACT: The aim of this work was to study the production of exopolysaccharide (EPS) from a novel ustilaginomycetes yeast strain Pseudozyma sp. NII 08165. The culture produced 3.5g/l EPS on fourth day of fermentation in a glucose-based medium. The structural characterization revealed that the EPS was a polymer of glucose, galactose and mannose in the ratio of 2.4:5.0:2.6 with a molecular weight of 1.7 MDa. The pseudoplastic behaviour of aqueous EPS with a thermal stability up to 220°C indicated its potential utility as a thickening or gelling agent in food industry. SEM studies of the EPS showed that it had compact film-like structure, which could make it a useful in preparing plasticized films. The AFM studies showed that EPS had spike-shaped microstructure. Physical properties of the exopolysaccharide determined further indicated its possible potential in different industrial applications.
International journal of biological macromolecules 04/2013; · 2.37 Impact Factor
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ABSTRACT: Arsenic trioxide loaded biocompatible PHB-PVA(1) nanoparticles (<100nm in size) with folate functionalized surface were synthesized using poly-[(R)-3-hydroxybutyric acid] (PHB) produced by Bacillus firmus NII 0830. Folate functionalization was carried using dicyclohexyl carbodiimide (DCC) as a catalyst and 10-bromodecanol as a linker to conjugate glutamic acid terminal of folate with the hydroxylate groups present on the surface of PHBA-PVA(2) nanotrojans. The effect of fabrication parameters on shape, size distribution and PDI of the PHB nanoparticles were also investigated. It was observed that increase in sonication time and polyvinyl alcohol (PVA) concentration greatly reduced the size of nanoparticles. The drug release studies on arsenic trioxide incorporated PHB-PVA nanoparticles were conducted at physiological pH and temperature. FOL-PHBA-PVA(3) nanoparticles showed greater extent of cytotoxicity towards murine fibrosarcoma L929 cells than PHBA-PVA nanoparticles alone without conjugated folate, indicating the significance of folate as ligand for specific targeting of FR+ cancer cells.
Bioresource technology 01/2013; · 4.25 Impact Factor
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ABSTRACT: Biobutanol from lignocellulosic biomass has gained much attention due to several advantages over bioethanol. Though microbial production of butanol through ABE fermentation is an established technology, the use of lignocellulosic biomass as feedstock presents several challenges. In the present study, biobutanol production from enzymatic hydrolysate of acid pretreated rice straw was evaluated using Clostridium sporogenes BE01. This strain gave a butanol yield of 3.43g/l and a total solvent yield of 5.32g/l in rice straw hydrolysate supplemented with calcium carbonate and yeast extract. Hydrolysate was analyzed for the level of inhibitors such as acetic acid, formic acid and furfurals which affect the growth of the organism and in turn ABE fermentation. Methods for preconditioning the hydrolysate to remove toxic end products were done so as to improve the fermentation efficiency. Conditions of ABE fermentation were fine tuned resulting in an enhanced biobutanol reaching 5.52g/l.
Bioresource technology 01/2013; · 4.25 Impact Factor
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ABSTRACT: The extensive use of synthetic plastics has caused serious waste disposal problems in our environment. Poly-3-hydroxybutyrates (PHB) are eco-friendly bacterial polyest-ers which are produced under unbalanced nutrient condi-tions. Few reports are available on PHB production by solid state fermentation (SSF). We have developed a novel SSF bioprocess in which polyurethane foam (PUF) is used as a physical inert support for the production of PHB by Bacillus sphaericus NII 0838. Media engineering for optimal PHB production was carried out using response surface method-ology (RSM) adopting a Box–Behnken design. The factors optimized by RSM were inoculum size, pH and (NH 4) 2 SO 4 concentration. Under optimized conditions—6.5 % inocu-lum size, 1.7 % (w/v) (NH 4) 2 SO 4 and pH 9.0—PHB pro-duction and biomass were 0.169±0.03 and 0.4±0.002 g/g PUF, respectively. This is the first report on PHB production by SSF using PUF as an inert support. Our results demon-strate that SSF can be used as an alternative strategy for the production of PHB.
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01/2013: pages 75 - 88;
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ABSTRACT: One of the major challenges in the bioconversion of lignocellulosic biomass into liquid biofuels includes the search for a glucose tolerant beta-gulucosidase. Beta-glucosidase is the key enzyme component present in cellulase and completes the final step during cellulose hydrolysis by converting the cellobiose to glucose. This reaction is always under control as it gets inhibited by its product glucose. It is a major bottleneck in the efficient biomass conversion by cellulase. To circumvent this problem several strategies have been adopted which we have discussed in the article along with its production strategies and general properties. It plays a very significant role in bioethanol production from biomass through enzymatic route. Hence several amendments took place in the commercial preparation of cellulase for biomass hydrolysis, which contains higher and improved beta-glucosidase for efficient biomass conversion. This article presents beta-glucosidase as the key component for bioethanol from biomass through enzymatic route.
Bioresource technology 09/2012; · 4.25 Impact Factor
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ABSTRACT: Three fractions of the endo-polysaccharides from the mycelium of Hericium erinaceus (HEP) grown on tofu whey were obtained by the fractional precipitation with gradient concentrations of ethanol (HEP40, HEP60 and HEP80). The chemical and physical characteristics of the three crude polysaccharides were investigated by the combination of chemical and instrumental analysis methods. The studies to evaluate the antioxidant potential and the hepatoprotective effects of the three polysaccharides showed that they had different activities in different evaluation system. HEP80 showed strong activity on antioxidant in vitro and potent hepatoprotective effect in vivo and the hepatoprotective effect may be due to its potent antioxidant capacity. The HEP could be exploited as antioxidant product and a supplement in the prevention of hepatic diseases. The study also opens an avenue for the efficient utilization of tofu whey, which is usually discarded in environment, causing concerns.
International journal of biological macromolecules 09/2012; 51(5):1140-6. · 2.37 Impact Factor
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ABSTRACT: As a biodegradable polyester, polylactide (PLA) has applications as a packaging material, in biomedical fields and tissue engineering. With the dual aim of improving its properties and biodegradability, PLA was blended with other polymers such as gum arabic, thermoplastic starch, microcrystalline cellulose, polyethylene glycol and polyhydroxy butyrate in 1:1 (w/w) by melt-blending technique. The thermal properties of the blends were compared with that of unblended PLA by thermo-gravimetric analysis. Biodegradation using Lentzea waywayandensis was in the order of PLA-gum arabic > PLA-thermoplastic starch > PLA(virgin) > PLA-microcrystalline cellulose > PLA-polyethylene glycol > PLA-polyhydroxy butyrate. Weight loss of 99 % (w/w) was noted within 4 days for PLA-thermoplastic starch and PLA-gum arabic blends.
Biotechnology Letters 07/2012; 34(11):2031-5. · 1.68 Impact Factor
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ABSTRACT: The aim of the present study was to evaluate the efficiency of amino peptidase (AP) from Streptomyces gedanensis to produce protein hydrolysates (PHs) with better antioxidant, nutritional, and functional properties and to compare it with the PHs produced by commercial protease. Three proteins, soy, casein, and wheat protein were employed to produce their hydrolysates by applying 2% (w/w) AP at optimal conditions of pH 8.5 and temperature 55 °C. The results disclosed that the degree of hydrolysis ranges from 15.93 to 20.68% after 6 h showed better antioxidant activity and functional properties such as solubility, foaming properties, and water holding capacity than the commercial protease treated hydrolysates. AP treated PHs were enriched in Glu followed by Leu, Tyr, Lys, Phe, Asp, Met, His, Ile, Ala, and Val. Therefore, S. gedanensis AP would be an attractive microbial AP with high potential for the preparation of PHs which could offer industrial applications especially in the realm of producing food formulations as food additives in medicine and sport. PRACTICAL APPLICATION: AP from S. gedanensis was found to be the most effective enzyme to produce PHs with good antioxidant, nutritional, and functional properties. The antioxidant and essential amino acids of AP treated PHs unveiled that this amino peptidase could give credence to eliminate the bitter taste by hydrolysis of peptides and could offer interesting possibilities for industrial applications, including debittering of protein hydrolysates. The findings could be useful in the food industry especially in the realm of producing food formulations requiring high protein supplements.
Journal of Food Science 07/2012; 77(7):C791-7. · 1.66 Impact Factor
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ABSTRACT: A potential bacterial strain designated as NII-0928 isolated from Western ghat forest soil with multiple plant growth promoting attributes, and it has been identified and characterized. Plant growth promoting
traits were analyzed by determining the P-solubilization efficiency, Indole acetic acid production, HCN, siderophore production
and growth in nitrogen free medium. It was able to solubilize phosphate (76.6μgml−1), and produce indole acetic acid (58.9μgml−1) at 28±2°C. Qualitative detection of siderophore production and HCN were also observed. At 5°C it was found to express
all the plant growth promotion attributes except HCN production. The ability to colonize roots is a sine qua non condition
for a rhizobacteria to be considered a true plant growth-promoting rhizobacteria (PGPR). 16S rRNA gene sequencing reveals
the identity of the isolate as Serratia nematodiphila with which it shares highest sequence similarity (99.4%). Seed bacterization with black pepper cuttings in greenhouse trials
using Sand: Soil: FYM with three individual experimental sets with their respective control showed clearly the growth promoting
activity. Hence, Serratia nematodiphila NII-0928 is a promising plant growth promoting isolate showing multiple PGPR attributes that can significantly influence
black pepper cuttings. The result of this study provides a strong basis for further development of this strain as a bioinoculants
to attain the desired plant growth promoting activity in black pepper growing fields.
KeywordsPlant growth promotion–Black pepper–
Serratia nematodiphila
World Journal of Microbiology and Biotechnology 04/2012; 27(2):259-265. · 1.53 Impact Factor
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ABSTRACT: A Gram-positive rod-shaped bacterium isolated on nutrient agar plates incubated at 28±2°C. The identity of the bacterium
was confirmed by sequencing of the 16S rRNA gene and it reveals that it shares highest similarity with Bacillus thioparus CECT 7196T (99.08%). It was capable of growing at temperatures ranging from 4 to 40°C, but optimum growth was observed at 28±2°C.
Strain NII-0902 is endowed with multiple plant growth promotion attributes such as phosphate solubilization, Indole acetic
acid (IAA), siderophore and HCN production, which were expressed differentially at sub-optimal temperatures (5–40°C). It was
able to solubilize phosphate (17.7μgml−1), and produce IAA (139.7μgml−1) at 28±2°C. Qualitative detection of siderophore production and HCN were also observed. At 5°C it was found to express
all the plant growth promotion attributes except HCN production. The ability to colonize roots is a sine qua non condition
for a rhizobacteria to be considered a true plant growth-promoting rhizobacteria (PGPR). Bacillus sp. NII-0902 has a potential ability to colonize roots visualized by transparency, bacterial growth (turbid, milky and narrow
zone) along and around roots and truly supported by scanning electron micrograph. Hence, it is proposed that, Bacillus thioparus sp. NII-0902 could be deployed as an inoculant to attain the desired results of bacterization.
KeywordsPGPR–
Bacillus
–16S rRNA sequencing–Western ghat
World Journal of Microbiology and Biotechnology 04/2012; 26(12):2277-2283. · 1.53 Impact Factor
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ABSTRACT: Raw starch is the most abundant source of glucose in the world. Therefore, finding enzymes capable of digesting raw starch
would find high industrial demand. The α-amylase gene of Bacillus amyloliquefaciens ATCC 23842 was amplified, cloned and overexpressed in Escherichia coli BL21 (DE3) cells. The recombinant enzyme was purified to apparent homogeneity using ion exchange and gel filtration chromatography.
The raw-starch digestibility of the purified enzyme was characterized by studying the hydrolysis and adsorption rate on a
variety of raw starches (potato, cassava, corn, wheat and rice). The raw-starch digestion was further confirmed by scanning
electron microscopy studies, which revealed an effective rate of hydrolysis. The kinetic studies revealed a relatively low
K
m of 2.76 mg/mL, exhibiting high affinity towards the soluble starch as the most preferred substrate and the inhibition kinetic
studies revealed a high K
i value (350 mM).
Key words
Bacillus amyloliquefaciens
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α-amylase-cloning-overexpression-raw starch digestion
Biologia 04/2012; 65(3):392-398. · 0.56 Impact Factor
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ABSTRACT: The capacity to sense and respond to light is widespread in animals, plants, fungi and bacteria. The effect of light quality
on growth and pigment yield of Monascus purpureus was investigated. Incubation in total darkness increased red pigment production from 14. 5 OD/g dry substrate to 22 OD/g
dry substrate. In contrast, growth of the fungus in direct illumination resulted in total suppression of pigment production.
It was found that both red and blue light influenced pigment yield as well as culture morphology. The authors propose the
existence of a light-perception system in Monascus purpureus.
World Journal of Microbiology and Biotechnology 04/2012; 24(11):2671-2675. · 1.53 Impact Factor
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ABSTRACT: The efficacy of four potential phosphate solubilizing Enterobacter isolated from non-rhizospheric soil in Western ghat forest in India. Plant growth promoting ability of these isolates was evaluated in cowpea. All are gram negative, rod shaped,
0.8–1.6mm in size, and psychrotrophic in nature, grow from 5 to 40°C (optimum temp. 28±2°C). All isolates exhibits growth
at a wide range of pH 6–12, optimum at pH 7.0 and tolerates up to 7% (w/v) salt concentration. 16S rRNA gene sequencing reveals
the confirmation of isolates to Enterobacter aerogenes sp. (NII-0907 and NII-0929), Enterobacter cloacae subsp. cloacae sp. (NII-0931) and Enterobacter asburiae sp. (NII-0934) with which they share >99% sequence similarity. Under in vitro conditions, all the four isolates were found
to produce indole acetic acid, P-solubilization and hydrogen cyanide. The P-solubilizing activity coincided with a concomitant
decrease in pH of the medium (pH 7.0–<3.0). The plant growth promotion properties were demonstrated through a cow pea (Vigna unguiculata (L.) walp) based bioassay under greenhouse conditions. Although the bacterial inoculation was found to result in significant increment
in root, shoot and biomass and it stimulated bacterial counts in the rhizosphere. Hence, these isolates can further formulated
and used for field application.
KeywordsPGPR activity-
Enterobacter sp.-16S rRNA-Western ghat
World Journal of Microbiology and Biotechnology 04/2012; 26(7):1233-1240. · 1.53 Impact Factor
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ABSTRACT: A phosphate solubilizing and antagonistic bacterial strain, isolated from a Western Ghat forest soil in Kerala province, India
(designated as NII-0906), showed cold tolerance and grew from 10 to 37°C (optimum temperature 30°C). It was a Gram-positive,
rod shaped, 0.8–1.6 μm in size, and exhibited tolerance to a wide pH range (5–12; optimum 7.0) and salt concentration up to
7% (w/v). The isolate showed maximum similarity with Exiguobacterium marinum TF-80T based on 16S rRNA analysis. It solubilized tricalcium phosphate under in vitro conditions. The phosphate solubilization was
estimated along a temperature range (5–40°C), and maximum activity (84.7 μg mL−1 day−1) was recorded at 30°C after 10 days of incubation. The phosphate solubilizing activity coincided with a concomitant decrease
in pH of the medium. The isolate also exhibited antifungal activity against phytopathogenic fungi in Petri dish assays and
produced siderophore and hydrogen cyanide. The strain’s plant growth promotion properties were demonstrated through a cowpea-based
bioassay under greenhouse conditions. The bacterial inoculation resulted in significant increment in plant root, stem and
as well as in plant biomass. Further, scanning electron microscopic study revealed the root colonization in cowpea. These
results could offer potential perspective for the strain to be used as plant growth-promoting rhizobacteria, which could be
used as an inoculant for regional crops.
Key words
Exiguobacterium species-plant growth promoting attributes-antagonistic activity
Biologia 04/2012; 65(2):197-203. · 0.56 Impact Factor
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ABSTRACT: A Gram positive, rod-shaped potential strain was selected from the pool of bacterial isolates obtained from the Western Ghats
forest (India) on the basis of zone of P-solubilization activity. Identification based on 16S rRNA gene sequence revealed
that the strain is of Bacillus species, sharing highest sequence similarity to Bacillus tequilensis NRRL B-41771T (99.5%). Strain NII-0943 was able to produce good amount of indole acetic acid (IAA) and was positive for siderophore production.
In addition to IAA and siderophore attributes, strain NII-0943 also possessed the characteristics like Ca3(PO4)2 solubilization and growth in nitrogen-free medium. Seed inoculation with the strain NII-0943 resulted in significantly higher
root initiation in black pepper cuttings grown under pots. The contents of nitrogen and phosphorus in both soil and plant
were also enhanced significantly in treatments inoculated with these bacterial inocula. Hence, based on this evidence it is
proposed that strain NII-0943 could be deployed as a plant growth-promoting inoculant to attain the desired results of bacterization.
Key words
Bacillus tequilensis
–plant growth activity–black pepper–16S rRNA gene
Biologia 04/2012; 66(5):801-806. · 0.56 Impact Factor
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ABSTRACT: Laccases are oxidative enzymes linked to biological degradation of lignin. The aim of this work was to evaluate the effect of inducers and different concentrations of nitrogen on production level of total laccase activity and pattern of laccase isoforms, produced in solid state fermentation of sugarcane bagasse by a selected strain of Pleurotus ostreatus. The addition of yeast extract 5 g/L, copper sulfate 150 μM and ferulic acid 2 mM provided highest enzymatic activity (167 U/g) and zymograms indicated the presence of six laccase isoforms (POXA1b, POXA3, POXC and three other isoforms). Results of protein identification by mass spectrometry confirmed the presence of POXC and POXA3 as the main isoenzymes, and also identified a glyoxal oxidase and three galactose oxidases. The fact that the isoenzyme POXA1b was not identified in the analyzed samples can be possibly explained by its sensitivity to protease degradation.
Bioresource technology 03/2012; 114:735-9. · 4.25 Impact Factor
