Abstract: The isolated cyanobacterium containing biopigments like chlorophyll-a, phycoerythrin, phycocyanin, and carotenoid was cultured under different quality of light modes to ascertain biomass and pigment productivity. On the basis of 16S rRNA gene sequence, the isolate was identified as Pseudanabaena sp. Maximum biomass concentration obtained in white-, blue-, and green-light was 0.82, 0.94, and 0.89 g/L, respectively. It was observed that maximum phycoerythrin production was in green light (39.2 mg/L), ensued by blue light (32.2 mg/L), while phycocyanin production was maximum in red light (10.9 mg/L). In yellow light, pigment production as well as the growth rate gradually declined after 12 days. Carotenoid production decreased in blue-, white-, and red-light after 15 days, while in green light it had increased gradually. The present communication suggests that Pseudanabaena sp. can be used for commercial production of phycoerythrin when grown under green light.
Abstract: C-phycoerythrin was isolated and purified from marine Pseudanabaena sp. using two step chromatographic methods. Phycobiliproteins in the marine Pseudanabaena was extracted in 100 mM phosphate buffer (pH 7.2) and precipitated by salting out. The precipitated C-phycoerythrin was purified by gel filtration with Sephadex G-150, and then it was purified by ion exchange chromatography on DEAE cellulose, which was developed by linear ionic strength gradients. Purified phycoerythrin showed absorption maxima at 568 and 541 nm, and displayed a fluorescence maximum at 578 nm. The absorbance ratio A₅₆₈/A₂₈₀, a criterion for purity (purity ratio) achieved was 6.86. It showed a single band on examination by polyacrylamide gel electrophoresis (PAGE). The polypeptide analysis of the purified C-phycoerythrin by SDS-PAGE demonstrated that it contained two chromophore-carrying subunits. The yield of purified C-phycoerythrin obtained was 13.6 mg/g of the cell dry weight with 47% of yield. Obtaining highly pure C-phycoerythrin allows one to evaluate its fluorescence properties for future applications in biochemical and biomedical research.
Abstract: Two chromogenic complexes, L.Zn (where L is (E)-4-((4-(1,4,8,11-tetraazacyclotetradecan-1-ylsulfonyl)phenyl)diazenyl)-N,N-dimethylaniline) and its [2]pseudorotaxane form (α-CD.L.Zn), were found to bind preferentially to adenosine triphosphate (ATP), among all other common anions and biologically important phosphate (AMP, ADP, pyrophosphate, and phosphate) ions in aqueous HEPES buffer medium of pH 7.2. Studies with live cell cultures of prokaryotic microbes revealed that binding of these two reagents to intercellular ATP, produced in situ, could be used in delineating the gram-positive and the gram-negative bacteria. More importantly, these dyes were found to be nontoxic to living microbes (eukaryotes and prokaryotes) and could be used for studying the cell growth dynamics. Binding to these two viable staining agents to intercellular ATP was also confirmed by spectroscopic studies on cell growth in the presence of different respiratory inhibitors that influence the intercellular ATP generation.
Abstract: PHAs are biodegradable and environmentally friendly thermoplastics. The major contributor to PHA production cost is carbon substrate cost, therefore it is desirable to produce PHA from waste/byproducts like Jatropha biodiesel byproducts. This study was done using Jatropha biodiesel byproduct as carbon source, to decrease production cost for PHAs. Total 41 isolates from soil and marine source were able to utilize Jatropha biodiesel byproduct. Nine bacteria were selected for further studies, which were found positive for Nile red viable colony screening. Two bacterial isolates SM-P-1S and SM-P-3M isolated from soil and marine environment respectively, were found promising for PHA production. PHA accumulation for SM-P-1S and SM-P-3M was 71.8% and 75% PHA/CDW respectively and identified as Bacillus sonorensis and Halomonas hydrothermalis by MTCC. The PHA obtained from SM-P-1S and SM-P-3M was analyzed by FTIR and NMR as polyhydroxybutyrate (PHB).
Abstract: Amylases are the most important hydrolytic enzymes for starch-based industries. It is desirable that alpha-amylases should be active at high temperature of gelatinization (100-110 degrees C) and liquefaction (80-90 degrees C) to economize processes. Therefore, thermostable and thermoactive enzyme from natural bacterial strain would have wide industrial importance. In the present study a highly thermoactive and thermostable amylase producing Bacillus sp. was isolated from experimental salt farm of Central Salt and Marine Chemicals Research Institute, yielding 452Uml(-1) amylase in medium containing (%) NaCl 0.5, peptone 0.5, beef extract 0.3, starch 1.0 at 37 degrees C, pH 7.0 after 48h of incubation. Maximum activity of amylase was observed at pH 8.0 and 110 degrees C temperature. The crude enzyme was highly active between pH 6.0 and 11.0 and observed to be active and thermostable after 30min of incubation at 60 degrees C. These properties indicated that the isolated alpha-amylase enzyme is suitable for starch liquefaction and other food processing.
Abstract: Specific recognition of CN(-) in sodium cyanide solution was achieved using two imidazole-based receptors (A and B). Visually detectable color changes were associated with the formation of hydrogen bonded adducts, A.CN(-) and B.CN(-). Ratiometric fluorescence response was achieved for receptor A on binding to CN(-), and this reagent was used for imaging bacterial cells pre-exposed to 1.42 microM CN(-) solution.
Abstract: Cyanobacteria have many unexploited potential for natural products with a huge variability in structure and biological activity. Their products are species specific and substrate+growth condition specific. Under stress conditions they are reported to produce biopolymers like EPS and PHA, which can be produced extracellularly and intracellularly, respectively. Polyhydroxyalkanoates are polymers of biological origin, they are also capable of being completely broken down to water and carbon dioxide by microorganisms found in a wide range of environments, such as soil, water, and sewage. We have studied marine cyanobacteria Spirulina subsalsa from Veraval coast, Gujarat, India, producing PHA under increased sodium chloride (NaCl) concentration (5% enhancement to the ASNIII medium), The biopolymer was chemically characterized through FTIR, NMR, TGA, and DSC. The present study shows increased PHA accumulation in S. subsalsa by twofold increased NaCl concentration in the growth media.
Abstract: C-Phycoerythrin is water soluble red color chromo-protein, which is used as a natural food colorant. The effect of selected edible preservatives like citric acid, sodium chloride, sucrose and calcium chloride on the stability of C-Phycoerythrin at 0±5°C and 35±5°C was studied in aqueous solution. Experiment was carried out to select a stabilizing agent having Hofmeister series behavior acting on hydrophobic interactions. The denaturation of phycoerythrin with urea as denaturant and effect of different pH on C-Phycoerythrin was studied. Citric acid (4 mg/ml) was observed to be one of the best preservative for C-Phycoerythrin at 35±5°C and 0±5°C in aqueous solution for 45 days. Citric acid was able to maintain the stability of C-Phycoerythrin in the solution. The amount of C-Phycoerythrin left in the solution containing citric acid after 30 and 45 days was 46 and 37.8% respectively at higher temperature.
Abstract: Selective colorimetric detection of ATP in physiological conditions by a Zn(II)-based receptor is reported. This reagent was found to be non-toxic to the living cells and could be used for studying the growth of the yeast cells.
Abstract: A newly synthesized 1,4,8,11-tetraazacyclotetradecane derivative (L), functionalized with a diazo moiety as the reporter functionality, is found to bind specifically to Hg(2+) with an associated change in color that could be visually detected. With biologically benign β-CD, it forms an inclusion complex (L·2β-CD), which shows a much higher solubility in water, and this helps in developing a more intense color on binding to Hg(2+) in a CH(3)CN-HEPES buffer medium. The nontoxic nature of L was checked with the living cells of a Gram negative bacterium, Pseudomonas putida . Further, experiments revealed that these two reagents could be used as staining agents for the detection of Hg(2+) present in this microorganism.
Abstract: A tetrapyrrole-based chromophore was obtained through the methanolysis of C-phycocyanin extracted from Spirulina platensis, and was found to act as a selective receptor for Hg2+ at physiological pH conditions.
Abstract: The effect of selected edible preservatives, citric acid, sucrose and calcium chloride on the stability of C-phycocyanin (C-PC) at 0 ± 5 °C and 35 ± 5 °C was studied in aqueous solution. While screening the edible preservatives for a protein like C-phycocyanin, the denaturation of C-PC with urea as a denaturant and thermal unfolding studies through differential scanning calorimetry (DSC) was carried out to select a stabilizing agent having Hofmeister series behaviour acting on hydrophobic interactions. While studying the efficacy of edible preservatives, citric acid (4 mg/ml) was observed to be one of the best preservative for phycocyanin at 35 ± 5 °C in aqueous solution for 45 days with negligible loss which is comparable to the stability of C-PC at 0 ± 5 °C.
Calcium chloride and sucrose were also found to be effective in maintaining the stability of C-PC in aqueous phase, but at lower temperature. Citric acid was able to maintain the stability even at higher temperature lasting for more than 1 month in aqueous solution.
Abstract: The chromogenic complex 1 x Zn (where 1 is (E)-4-(4-dimethylamino-phenylazo)-N,N-bispyridin-2-ylmethyl-benzenesulfonamide) showed high affinity toward the phosphate ion in tetrabutylammonium phosphate in acetonitrile solution and could preferentially bind to adenosine triphosphate (ATP) in aqueous solution at physiological pH. This binding caused a visual change in color, whereas no such change was noticed with other related anions (adenosine monophosphate, adenosine diphosphate, pyrophosphate, and phosphate) of biological significance. Thus, 1 x Zn could be used as a staining agent for different biological cells through binding to the ATP, generated in situ by the mitochondria (in eukaryotes). For prokaryotes (bacteria) the cell membrane takes care of the cells' energy conversion, since they lack mitochondria. ATP is produced in their unique cell structure on the cell membrane, which is not found in any eukaryotes. These stained cells could be viewed with normal light microscopy. This reagent could even be used for distinguishing the gram-positive and the gram-negative bacteria (prokaryotes). This dye was found to be nonlipophilic in nature and nontoxic to living microbes (eukaryotes and prokaryotes). Further, stained cells were found to grow in their respective media, and this confirmed the maintenance of viability of the microbes even after staining, unlike with many other dyes available commercially.
Abstract: A new chromogenic complex 1.Zn has been synthesized, and its interactions with different biologically important phosphates have been investigated in aqueous solution (pH approximately 7.2). A visual color change can be detected on binding of ATP to 1.Zn, whereas no such change is observed when other biologically related anions (AMP, ADP, PPi, or Phosphate) are used. Complex 1.Zn can also be used as a staining agent for yeast cells allowing detection under normal light microscopy.
