The Experts below are selected from a list of 102 Experts worldwide ranked by ideXlab platform
Nirupama Mallick - One of the best experts on this subject based on the ideXlab platform.
-
role of cultural variables in tailoring poly 3 hydroxybutyrate co 3 hydroxyvalerate copolymer synthesis in the diazotrophic cyanobacterium Aulosira fertilissima ccc 444
Journal of Applied Phycology, 2015Co-Authors: Shilalipi Samantaray, Nirupama MallickAbstract:An important objective in the field of biopolymer research is to study the broad range of cultural conditions; by suitable choice of composition and processing conditions, polymer can often be tailor-made to have specific and desirable properties. Aulosira fertilissima CCC 444 when cultivated in a mixture of fructose and valerate produced poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] copolymer up to 537.5 mg L−1 containing 25 mol% 3HV monomers. Manipulation of the culture conditions such as varying pH, temperature, initial cell concentrations and dark incubation significantly affected the accumulation as well as composition of P(3HB-co-3HV) copolymer; therefore, the polymer finds a wider application. The molar fraction of 3HV tended to increase up to 35 mol% in the early phase of A. fertlissima cultivation, i.e. on the 7th day. An initial inoculum size of 80 mg dcw L−1 was found optimum for P(3HB-co-3HV) copolymer accumulation. Lower temperature conditions favoured the accumulation of copolymers containing higher molar fractions of 3HV monomers as compared to high temperature conditions. It was also observed that 3HV molar fractions in the copolymer can tailor up to 50 mol% by maintaining the pH of culture medium at 9.5, without significantly affecting the copolymer content (72 % dry cell weight). This opens up new possibilities of using A. fertilissima CCC 444 as a suitable feedstock for production of P(3HB-co-3HV) copolymer with varied 3HB and 3HV fractions for various industrial and pharmaceutical applications.
-
production of poly 3 hydroxybutyrate co 3 hydroxyvalerate co polymer by the diazotrophic cyanobacterium Aulosira fertilissima ccc 444
Journal of Applied Phycology, 2014Co-Authors: Shilalipi Samantaray, Nirupama MallickAbstract:Accumulation of poly(3-hydroxybutyrate-co-3-hydroxyvalerate), P(3HB-co-3HV), a well-known co-polymer of polyhydroxyalkanoates family, was investigated in a N2-fixing cyanobacterium, Aulosira fertilissima CCC 444, in presence of propionate and valerate in the culture medium. The most significant rise in P(3HB-co-3HV) co-polymer content up to 77 % of dry cell weight was recorded under 0.5 % fructose + 0.4 % valerate supplementation depicting a productivity of 38 mg L−1 day−1, which was further increased by 2.5-fold, i.e., up to 95 mg L−1 day−1 under P deficiency. Surface analysis revealed a regular and smooth surface for P(3HB-co-3HV) co-polymer, against rugged and porous surface of the homopolymer of poly-β-hydroxybutyrate. X-ray diffraction showed semi-crystalline nature of the P(3HB-co-3HV) co-polymer. The thermal and mechanical properties of the co-polymer are comparable with the chemoheterotrophic bacterial polymers, thus opens up possibilities of using cyanobacterial PHAs in various fields.
-
production and characterization of poly β hydroxybutyrate phb polymer from Aulosira fertilissima
Journal of Applied Phycology, 2012Co-Authors: Shilalipi Samantaray, Nirupama MallickAbstract:Biopolymers such as polyhydroxyalkanoates (PHAs) are a class of secondary metabolites with promising importance in the field of environmental, agricultural, and biomedical sciences. To date, high-cost commercial production of PHAs is being carried out with heterotrophic bacterial species. In this study, a photoautotrophic N2-fixing cyanobacterium, Aulosira fertilissima, has been identified as a potential source for the production of poly-β-hydroxybutyrate (PHB). An accumulation up to 66% dry cell weight (dcw) was recorded when the cyanobacterium was cultured in acetate (0.3%) + citrate (0.3%)-supplemented medium against 6% control. Aulosira culture supplemented with 0.5% citrate under P deficiency followed by 5 days of dark incubation also depicted a PHB accumulation of 51% (dcw). PHB content of A. fertilissima reached up to 77% (dcw) under P deficiency with 0.5% acetate supplementation. Optimization of process parameters by response surface methodology resulted into polymer accumulation up to 85% (dcw) at 0.26% citrate, 0.28% acetate, and 5.58 mg L−1 K2HPO4 for an incubation period of 5 days. In the A. fertilissima cultures pre-grown in fructose (1.0%)-supplemented BG 11 medium, when subjected to the optimized condition, the PHB pool boosted up to 1.59 g L−1, a value ∼50-fold higher than the control. A. fertilissima is the first cyanobacterium where PHB accumulation reached up to 85% (dcw) by manipulating the nutrient status of the culture medium. The polymer extracted from A. fertilissima exhibited comparable material properties with the commercial polymer. As compared with heterotrophic bacteria, carbon requirement in A. fertilissima for PHB production is lower by one order magnitude; thus, low-cost PHB production can be envisaged.
-
wastewater utilization for poly β hydroxybutyrate production by the cyanobacterium Aulosira fertilissima in a recirculatory aquaculture system
Applied and Environmental Microbiology, 2011Co-Authors: Shilalipi Samantaray, Jitendra Kumar Nayak, Nirupama MallickAbstract:Intensive aquaculture releases large quantities of nutrients into aquatic bodies, which can lead to eutrophication. The objective of this study was the development of a biological recirculatory wastewater treatment system with a diazotrophic cyanobacterium, Aulosira fertilissima, and simultaneous production of valuable product in the form of poly-β-hydroxybutyrate (PHB). To investigate this possible synergy, batch scale tests were conducted under a recirculatory aquaculture system in fiber-reinforced plastic tanks enhanced by several manageable parameters (e.g., sedimentation, inoculum size, depth, turbulence, and light intensity), an adequate combination of which showed better productivity. The dissolved-oxygen level increased in the range of 3.2 to 6.9 mg liter⁻¹ during the culture period. Nutrients such as ammonia, nitrite, and phosphate decreased to as low as zero within 15 days of incubation, indicating the system's bioremediation capability while yielding valuable cyanobacterial biomass for PHB production. Maximum PHB accumulation in A. fertilissima was found in sedimented fish pond discharge at 20-cm culture depth with stirring and an initial inoculum size of 80 mg dry cell weight (dcw) liter⁻¹. Under optimized conditions, the PHB yield was boosted to 92, 89, and 80 g m⁻², respectively for the summer, rainy, and winter seasons. Extrapolation of the result showed that a hectare of A. fertilissima cultivation in fish pond discharge would give an annual harvest of ∼17 tons dry biomass, consisting of 14 tons of PHB with material properties comparable to those of the bacterial polymer, with simultaneous treatment of 32,640 m³ water discharge.
Shilalipi Samantaray - One of the best experts on this subject based on the ideXlab platform.
-
role of cultural variables in tailoring poly 3 hydroxybutyrate co 3 hydroxyvalerate copolymer synthesis in the diazotrophic cyanobacterium Aulosira fertilissima ccc 444
Journal of Applied Phycology, 2015Co-Authors: Shilalipi Samantaray, Nirupama MallickAbstract:An important objective in the field of biopolymer research is to study the broad range of cultural conditions; by suitable choice of composition and processing conditions, polymer can often be tailor-made to have specific and desirable properties. Aulosira fertilissima CCC 444 when cultivated in a mixture of fructose and valerate produced poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] copolymer up to 537.5 mg L−1 containing 25 mol% 3HV monomers. Manipulation of the culture conditions such as varying pH, temperature, initial cell concentrations and dark incubation significantly affected the accumulation as well as composition of P(3HB-co-3HV) copolymer; therefore, the polymer finds a wider application. The molar fraction of 3HV tended to increase up to 35 mol% in the early phase of A. fertlissima cultivation, i.e. on the 7th day. An initial inoculum size of 80 mg dcw L−1 was found optimum for P(3HB-co-3HV) copolymer accumulation. Lower temperature conditions favoured the accumulation of copolymers containing higher molar fractions of 3HV monomers as compared to high temperature conditions. It was also observed that 3HV molar fractions in the copolymer can tailor up to 50 mol% by maintaining the pH of culture medium at 9.5, without significantly affecting the copolymer content (72 % dry cell weight). This opens up new possibilities of using A. fertilissima CCC 444 as a suitable feedstock for production of P(3HB-co-3HV) copolymer with varied 3HB and 3HV fractions for various industrial and pharmaceutical applications.
-
production of poly 3 hydroxybutyrate co 3 hydroxyvalerate co polymer by the diazotrophic cyanobacterium Aulosira fertilissima ccc 444
Journal of Applied Phycology, 2014Co-Authors: Shilalipi Samantaray, Nirupama MallickAbstract:Accumulation of poly(3-hydroxybutyrate-co-3-hydroxyvalerate), P(3HB-co-3HV), a well-known co-polymer of polyhydroxyalkanoates family, was investigated in a N2-fixing cyanobacterium, Aulosira fertilissima CCC 444, in presence of propionate and valerate in the culture medium. The most significant rise in P(3HB-co-3HV) co-polymer content up to 77 % of dry cell weight was recorded under 0.5 % fructose + 0.4 % valerate supplementation depicting a productivity of 38 mg L−1 day−1, which was further increased by 2.5-fold, i.e., up to 95 mg L−1 day−1 under P deficiency. Surface analysis revealed a regular and smooth surface for P(3HB-co-3HV) co-polymer, against rugged and porous surface of the homopolymer of poly-β-hydroxybutyrate. X-ray diffraction showed semi-crystalline nature of the P(3HB-co-3HV) co-polymer. The thermal and mechanical properties of the co-polymer are comparable with the chemoheterotrophic bacterial polymers, thus opens up possibilities of using cyanobacterial PHAs in various fields.
-
production and characterization of poly β hydroxybutyrate phb polymer from Aulosira fertilissima
Journal of Applied Phycology, 2012Co-Authors: Shilalipi Samantaray, Nirupama MallickAbstract:Biopolymers such as polyhydroxyalkanoates (PHAs) are a class of secondary metabolites with promising importance in the field of environmental, agricultural, and biomedical sciences. To date, high-cost commercial production of PHAs is being carried out with heterotrophic bacterial species. In this study, a photoautotrophic N2-fixing cyanobacterium, Aulosira fertilissima, has been identified as a potential source for the production of poly-β-hydroxybutyrate (PHB). An accumulation up to 66% dry cell weight (dcw) was recorded when the cyanobacterium was cultured in acetate (0.3%) + citrate (0.3%)-supplemented medium against 6% control. Aulosira culture supplemented with 0.5% citrate under P deficiency followed by 5 days of dark incubation also depicted a PHB accumulation of 51% (dcw). PHB content of A. fertilissima reached up to 77% (dcw) under P deficiency with 0.5% acetate supplementation. Optimization of process parameters by response surface methodology resulted into polymer accumulation up to 85% (dcw) at 0.26% citrate, 0.28% acetate, and 5.58 mg L−1 K2HPO4 for an incubation period of 5 days. In the A. fertilissima cultures pre-grown in fructose (1.0%)-supplemented BG 11 medium, when subjected to the optimized condition, the PHB pool boosted up to 1.59 g L−1, a value ∼50-fold higher than the control. A. fertilissima is the first cyanobacterium where PHB accumulation reached up to 85% (dcw) by manipulating the nutrient status of the culture medium. The polymer extracted from A. fertilissima exhibited comparable material properties with the commercial polymer. As compared with heterotrophic bacteria, carbon requirement in A. fertilissima for PHB production is lower by one order magnitude; thus, low-cost PHB production can be envisaged.
-
wastewater utilization for poly β hydroxybutyrate production by the cyanobacterium Aulosira fertilissima in a recirculatory aquaculture system
Applied and Environmental Microbiology, 2011Co-Authors: Shilalipi Samantaray, Jitendra Kumar Nayak, Nirupama MallickAbstract:Intensive aquaculture releases large quantities of nutrients into aquatic bodies, which can lead to eutrophication. The objective of this study was the development of a biological recirculatory wastewater treatment system with a diazotrophic cyanobacterium, Aulosira fertilissima, and simultaneous production of valuable product in the form of poly-β-hydroxybutyrate (PHB). To investigate this possible synergy, batch scale tests were conducted under a recirculatory aquaculture system in fiber-reinforced plastic tanks enhanced by several manageable parameters (e.g., sedimentation, inoculum size, depth, turbulence, and light intensity), an adequate combination of which showed better productivity. The dissolved-oxygen level increased in the range of 3.2 to 6.9 mg liter⁻¹ during the culture period. Nutrients such as ammonia, nitrite, and phosphate decreased to as low as zero within 15 days of incubation, indicating the system's bioremediation capability while yielding valuable cyanobacterial biomass for PHB production. Maximum PHB accumulation in A. fertilissima was found in sedimented fish pond discharge at 20-cm culture depth with stirring and an initial inoculum size of 80 mg dry cell weight (dcw) liter⁻¹. Under optimized conditions, the PHB yield was boosted to 92, 89, and 80 g m⁻², respectively for the summer, rainy, and winter seasons. Extrapolation of the result showed that a hectare of A. fertilissima cultivation in fish pond discharge would give an annual harvest of ∼17 tons dry biomass, consisting of 14 tons of PHB with material properties comparable to those of the bacterial polymer, with simultaneous treatment of 32,640 m³ water discharge.
Tasneem Fatma - One of the best experts on this subject based on the ideXlab platform.
-
Screening of cyanobacterial strains for UV screening compound Scytonemin - Environmental Perspectives
2020Co-Authors: Saman Mushir, Satyanarayan Deep, Tasneem FatmaAbstract:Abstract: Cyanobacteria has evolved the capacity to synthesize, mount up and metabolize scytonemin a photoprotective pigment as a part of an overall tactic to taper the unswerving and oblique destructive effects of environmental ultraviolet radiation (UVR) due to the deterioration of ozone layer attributable to the release of pollution containing the chemicals chlorine and bromine. Scytonemin is an indole phenolic pigment found in the sheath of many cyanobacteria having a unique dimeric structure, ecological importance and novel pharmaceutical activity have enthused substantial pursuit in its biosynthesis. This study includes the screening of scytonemin from 46 studied cyanobacterial strains out of which 23 showed the presence of scytonemin. Aulosira fertilissima showed the maximum scytonemin. The effect of environmental factors, including Light intensity, photoperiod, UV-light was studied on scytonemin synthesis of A. fertilissima. A remarkable change in scytonemin synthesis was observed under UV-light stress. Scytonemin increased under all stress conditions but it increased maximally under UV-light stress
-
screening of cyanobacterial strains for uvscreening compound scytonemin environmental perspectives
International Journal of Innovative Research in Science Engineering and Technology, 2014Co-Authors: Saman Mushir, Satyanarayan Deep, Tasneem FatmaAbstract:Cyanobacteria has evolved the capacity to synthesize, mount up and metabolize scytonemin a photoprotective pigment as a part of an overall tactic to taper the unswerving and oblique destructive effects of environmental ultraviolet radiation (UVR) due to the deterioration of ozone layer attributable to the release of pollution containing the chemicals chlorine and bromine. Scytonemin is an indole phenolic pigment found in the sheath of many cyanobacteria having a unique dimeric structure, ecological importance and novel pharmaceutical activity have enthused substantial pursuit in its biosynthesis. This study includes the screening of scytonemin from 46 studied cyanobacterial strains out of which 23 showed the presence of scytonemin. Aulosira fertilissima showed the maximum scytonemin. The effect of environmental factors, including Light intensity, photoperiod, UV-light was studied on scytonemin synthesis of A. fertilissima. A remarkable change in scytonemin synthesis was observed under UV-light stress. Scytonemin increased under all stress conditions but it increased maximally under UV-light stress
-
monitoring stress responses in cyanobacterial scytonemin screening and characterization
Environmental Technology, 2012Co-Authors: Saman Mushir, Tasneem FatmaAbstract:Scytonemin is believed to protect a variety of organisms against the negative effects of ultraviolet radiation. Cyanobacteria have evolved different strategies to minimize the potential damage caused by solar ultraviolet radiation. This includes the synthesis of the UV-absorbing compound scytonemin, which acts as a sunscreen During the present study scytonemin was found in 9 out of 19 studied cyanobacterial strains. Aulosira fertilissima showed the maximum amount of scytonemin. The effect of environmental factors, including temperature, light intensity, UV-light and salt was studied on scytonemin synthesis of A. fertilissima. A remarkable change in scytonemin synthesis was observed under salt stress and UV-light stress. Scytonemin increased under all stress conditions but it increased maximally under yellow-light stress.
-
ultraviolet radiation absorbing mycosporine like amino acids in cyanobacterium Aulosira fertilissima environmental perspective and characterization
2011Co-Authors: Saman Mushir, Tasneem FatmaAbstract:The aim of this study is to screen cyanobacterial strains for the high yield of Mycosporine-like amino acids and further the effect of various physicochemical conditions were also observed for its highest yield. Cyanobacteria are one of the most primitive organisms capable of MAAs synthesis. The UV screening compounds MAAs are usually accumulated intracellularly in cyanobacteria. Among the 18 strains, Aulosira fertilissima, showed the presence of highest amount of MAAs hence selected for the exposure of various physicochemical conditions (pH, light quality, UV-light, photoperiod and temperature). MAAs content was highly increased by UV exposure. 20 min exposure of UV-light induces three times highest amount of MAAs as compared to control. In the presence of pH stress also the content of MAAs was approximately three times higher than control while light quality and temperature had very little effect on MAA concentration. The high- performance liquid chromatographic analysis of water-soluble compounds reveals the biosynthesis of two MAAs, porphyra-334 (8_max = 334 nm) and shinorine (8_max = 334 nm), with retention times of 3.5 and 2.3 min, respectively. Spectrophotometric analysis also showed absorption maxima at 334 nm.
Meenakshi Banerjee - One of the best experts on this subject based on the ideXlab platform.
-
algal filtrate a low cost substitute to synthetic growth regulators for direct organogenesis of embryo culture in jatropha curcas ratanjyot
Acta Physiologiae Plantarum, 2009Co-Authors: Sarika Shrivastava, Meenakshi BanerjeeAbstract:Jatropha curcas, the energy plant has attained great attention in recent years because of its biodiesel production potential and medicinal value. This makes it imperative to search for techniques for its rapid propagation. Our research communication has shown for the first time direct organogenesis without callus formation from embryo culture of Jatropha. All previous reports embody callusing before further propagation and use of whole seeds. We also report the very economical protocol for J. curcas using cyanobacterial culture filtrate (Aulosira fertilissima) in place of chemical hormones giving this paper a cutting edge to in vitro propagation of J. curcas. The result showed that the number of days taken for shoots and root induction was quicker by adding the cyanobacterial filtrate and shoot and root length was comparatively higher than the other treatment with synthetic plant growth regulator. The same trend was found for chlorophyll a and b. No such report previously has ever focused on the use of cyanobacterial filtrate on in vitro germination of J. curcas embryo to regenerate plants at a faster rate. Ex vitro rooting is a new approach, which will reduce the time for regeneration still further, is an area that is being presently tried out.
-
scavenging of nickel and chromium toxicity in Aulosira fertilissima by immobilization effect on nitrogen assimilating enzymes
Electronic Journal of Biotechnology, 2004Co-Authors: Meenakshi Banerjee, Shanoo Mishra, Jhuma ChatterjeeAbstract:*The ubiquity of heavy metals in the biosphere results in the introduction of high amounts of toxic metals into the food chain from various sources. In the present study, one of the strongest nitrogen fixing cyanobacterium of the rice fields, Aulosira fertilissima, was subjected to nickel and chromium stress and the ameliorating effect of immobilization was investigated. Cell immobilization could protect the organism’s growth against the toxicity of both heavy metals at LC50 as compared to lethal concentrations. The nitrate reductase activity in free cells treated with the metals was substantially inhibited but immobilized cells treated with 0.1 ppm nickel was not affected by the metal treatment. Cell immobilization also resulted in a significant protection against sublethal concentration of chromium but to a lesser degree than it did with sub- lethal levels of nickel. Control immobilized cells also had higher Nitrogenase activity than control free cells. Nickel and chromium addition markedly decreased the enzyme activity in free cells but immobilized cells exposed to sublethal concentrations of both metals could overcome this decrease. Glutamine synthetase showed similar response under immobilized conditions compared to free cells with both metals. The addition of algal filtrate in 3:1 ratio further increased the nitrogenase activity compared with immobilized cells treated with sublethal doses of both metals. Immobilization facilitated higher uptake of nickel as compared to chromium. The observations of the present study clearly demonstrate the protective effect of immobilization on Aulosira fertilissima against Nickel and chromium toxicity. Rice field ecosystem thus possess a bidirectional natural metal ameliorating system where Aulosira mats act as a naturally immobilized system and the decay of Aulosira along with other cyanobacteria act as natural chelators protecting the rice plants from deleterious effects of the heavy metals. Most importantly is that the immobilization process protects the cyanobacterial nitrogen fixing process allowing it to maintain nitrogen economy of the fields in spite of the presence of heavy metals.
-
effects of uv radiation on the rice field cyanobacterium Aulosira fertilissima
Environmental and Experimental Botany, 1996Co-Authors: Meenakshi Banerjee, Donatp HaderAbstract:Abstract The effects of UV radiation (5 W m −2 ) were studied in the cyanobacterium, Aulosira fertilissima . The organism was found to be sensitive to UV-B and, to a lesser extent, UV-A. Absorption spectra showed that the pigment content, particularly phycocyanin, severely decreased following UV exposures; the effect was more pronounced with UV-B than with UV-A. The organism was also very sensitive to solar radiation, and complete bleaching of the cells occurred following exposure of 2–3 hr. The absorption and fluorescence emission spectra of crude pigments after 3 hr of UV-B exposure (5 W m −2 ) decreased significantly, suggesting the loss of effective energy transfer from the accessory pigments to PS-II. SDS-PAGE analysis of the total protein profile of cells treated with UV-B showed a decrease in the protein content with increasing exposure time. Substantial decrease in the protein bands occurred after 3 hr of UV-B exposure (5 W m −2 ), particularly of those between 14.2 and 45 kDa.
Donatp Hader - One of the best experts on this subject based on the ideXlab platform.
-
effects of uv radiation on the rice field cyanobacterium Aulosira fertilissima
Environmental and Experimental Botany, 1996Co-Authors: Meenakshi Banerjee, Donatp HaderAbstract:Abstract The effects of UV radiation (5 W m −2 ) were studied in the cyanobacterium, Aulosira fertilissima . The organism was found to be sensitive to UV-B and, to a lesser extent, UV-A. Absorption spectra showed that the pigment content, particularly phycocyanin, severely decreased following UV exposures; the effect was more pronounced with UV-B than with UV-A. The organism was also very sensitive to solar radiation, and complete bleaching of the cells occurred following exposure of 2–3 hr. The absorption and fluorescence emission spectra of crude pigments after 3 hr of UV-B exposure (5 W m −2 ) decreased significantly, suggesting the loss of effective energy transfer from the accessory pigments to PS-II. SDS-PAGE analysis of the total protein profile of cells treated with UV-B showed a decrease in the protein content with increasing exposure time. Substantial decrease in the protein bands occurred after 3 hr of UV-B exposure (5 W m −2 ), particularly of those between 14.2 and 45 kDa.
