Random amplification of polymorphic DNA (RAPD) analysis using the polymerase chain reaction prove... more Random amplification of polymorphic DNA (RAPD) analysis using the polymerase chain reaction proved a useful technique in the biodiversity analysis of microorganisms but may lack reproducibility in the poorly standardized methodology. In the present investigation, the RAPD technique was optimized for characterizing cyanobacterial isolates in order to ensure its reproducibility and discriminatory power. Cyanobacterial isolates from the three genera, Anabaena , Nostoc and Calothrix were examined for the fragment patterns produced using different 10-mer RAPD primers and concentrations of different components (DNA template, primer and Taq polymerase) at two different annealing temperatures. It was observed that variations associated with all the parameters tested modified the fingerprinting pattern. For conditions not optimized, RAPD bands were faint and difficult to score. Therefore, a set of conditions for RAPD-PCR reaction has been defined, to ensure simple and fast reproducibility.
Grain legumes are an important component of sustainable agri-food systems. They establish symbiot... more Grain legumes are an important component of sustainable agri-food systems. They establish symbiotic association with rhizobia and arbuscular mycorrhizal fungi, thus reducing the use of chemical fertilizers. Several other free-living microbial communities (PGPR—plant growth promoting rhizobacteria) residing in the soil-root interface are also known to influence biogeochemical cycles and improve legume productivity. The growth and function of these microorganisms are affected by root exudate molecules secreted in the rhizosphere region. PGPRs produce the chemicals which stimulate growth and functions of leguminous crops at different growth stages. They promote plant growth by nitrogen fixation, solubilization as well as mineralization of phosphorus, and production of phytohormone(s). The co-inoculation of PGPRs along with rhizobia has shown to enhance nodulation and symbiotic interaction. The recent molecular tools are helpful to understand and predict the establishment and function o...
Effects of the environmental variables such as light intensity (Vmol photons m⁻² S⁻¹), temperatur... more Effects of the environmental variables such as light intensity (Vmol photons m⁻² S⁻¹), temperature (*C) and CO₂ concentration (ppm) on chlorophyll, total soluble proteins and lipids were studied in selected microalgal strains from Chlorophyceae (Chlamydomonas sp., Scenedesmus sp., Chlorella sp., Kirchneriella sp.) and cyanobacteria (Nostoc sp.1, Anabaena sp., Nostoc sp. 2, Cylindrospermum sp.). Cultures were grown under controlled conditions at the National Phytotron Facility, Indian Agricultural Research Institute (IARI), New Delhi. Our results showed that chlorophyll concentration enhanced with increased C0₂. Chlorella exhibited the highest chlorophyll at 850 ppm CO₂ and 28*C; for Chlamydomonas it was at 78 μmol photons m⁻² S⁻¹ light intensity. In Cylindrospernum, total soluble proteins decreased with enhanced C0₂, and were highest at 18*C. In Anabaena, a light intensity of 65 μmol photons m⁻² S⁻¹ was best for maximum total soluble proteins. In Chlorella, CO₂ @ 850 ppm was most su...
Microalgae are reported as the efficient source of renewable biodiesel which should be able to me... more Microalgae are reported as the efficient source of renewable biodiesel which should be able to meet the global demand of transport fuels. Present study is focused on assessment of wastewater grown indigenous microalga Chlorella sp. for fuel quality parameters. This was successfully grown in secondary treated waste water diluted with tap water (25% dilution) in glass house. The microalga showed a dry weight of 0.849 g L−1 with lipid content of 27.1% on dry weight basis on 21st day of incubation. After transesterification, the yield of fatty acid methyl ester was 80.64% with major fatty acids as palmitic, linoleic, oleic and linolenic. The physical parameters predicted from empirical equations in the biodiesel showed cetane number as 56.5, iodine value of 75.5 g I2 100 g−1, high heating value 40.1 MJ kg−1, flash point 135 °C, kinematic viscosity 4.05 mm2 s−1 with density of 0.86 g cm3 and cold filter plugging point as 0.7 °C. Fourier transform infra-red (FTIR), 1H, 13C NMR spectrum co...
... 12, No. 2, (NS) pp. 181-185 (April-June, 2007) SHORT COMMUNICATION PHYSIOLOGICAL CHARACTERIZA... more ... 12, No. 2, (NS) pp. 181-185 (April-June, 2007) SHORT COMMUNICATION PHYSIOLOGICAL CHARACTERIZATION OF CYANOBACTERIAL ISOLATES FROM ORISSA AND WEST BENGAL SUDHIR SAXENA, BV SINGH, SAURABH TIWARI AND DOLLY WATTAL DHAR* ...
ABSTRACT Cost-efficient harvesting of microalgae is a major challenge due to their small size and... more ABSTRACT Cost-efficient harvesting of microalgae is a major challenge due to their small size and often low concentration in the culture medium. The flocculation efficacy of different inorganic and organic amendments was evaluated on various microalgae genera—one strain each belonging to Chlamydomonas, Chlorococcum, two of Botryococcus, and of Chlorella. An improvised medium comprising of commercial grade urea, single super phosphate, and muriate of potash was used to grow the microalgae for flocculation experiments. High pH induced increased flocculation efficiency (72–76 %) in selected microalgal strains. Ferric chloride was found to be the most efficient for most of the microalgal strains, while maize starch and rice starch proved superior for Chlorella sp. MCC6 and Botryococcus sp. MCC32. Although the highest flocculation efficiency was obtained with inorganic flocculant, i.e., ferric chloride (87.3 %) with Botryococcus MCC31, this was comparable with rice starch (86.8 %) for Botryococcus MCC32. This study showed that widely available cheaper biopolymers such as rice starch, maize, and potato starch can be promising flocculants due to their better harvesting efficiency (>80 %) and low price, thereby contributing to economical production of biodiesel from algae.
Random amplification of polymorphic DNA (RAPD) analysis using the polymerase chain reaction prove... more Random amplification of polymorphic DNA (RAPD) analysis using the polymerase chain reaction proved a useful technique in the biodiversity analysis of microorganisms but may lack reproducibility in the poorly standardized methodology. In the present investigation, the RAPD technique was optimized for characterizing cyanobacterial isolates in order to ensure its reproducibility and discriminatory power. Cyanobacterial isolates from the three genera, Anabaena , Nostoc and Calothrix were examined for the fragment patterns produced using different 10-mer RAPD primers and concentrations of different components (DNA template, primer and Taq polymerase) at two different annealing temperatures. It was observed that variations associated with all the parameters tested modified the fingerprinting pattern. For conditions not optimized, RAPD bands were faint and difficult to score. Therefore, a set of conditions for RAPD-PCR reaction has been defined, to ensure simple and fast reproducibility.
Grain legumes are an important component of sustainable agri-food systems. They establish symbiot... more Grain legumes are an important component of sustainable agri-food systems. They establish symbiotic association with rhizobia and arbuscular mycorrhizal fungi, thus reducing the use of chemical fertilizers. Several other free-living microbial communities (PGPR—plant growth promoting rhizobacteria) residing in the soil-root interface are also known to influence biogeochemical cycles and improve legume productivity. The growth and function of these microorganisms are affected by root exudate molecules secreted in the rhizosphere region. PGPRs produce the chemicals which stimulate growth and functions of leguminous crops at different growth stages. They promote plant growth by nitrogen fixation, solubilization as well as mineralization of phosphorus, and production of phytohormone(s). The co-inoculation of PGPRs along with rhizobia has shown to enhance nodulation and symbiotic interaction. The recent molecular tools are helpful to understand and predict the establishment and function o...
Effects of the environmental variables such as light intensity (Vmol photons m⁻² S⁻¹), temperatur... more Effects of the environmental variables such as light intensity (Vmol photons m⁻² S⁻¹), temperature (*C) and CO₂ concentration (ppm) on chlorophyll, total soluble proteins and lipids were studied in selected microalgal strains from Chlorophyceae (Chlamydomonas sp., Scenedesmus sp., Chlorella sp., Kirchneriella sp.) and cyanobacteria (Nostoc sp.1, Anabaena sp., Nostoc sp. 2, Cylindrospermum sp.). Cultures were grown under controlled conditions at the National Phytotron Facility, Indian Agricultural Research Institute (IARI), New Delhi. Our results showed that chlorophyll concentration enhanced with increased C0₂. Chlorella exhibited the highest chlorophyll at 850 ppm CO₂ and 28*C; for Chlamydomonas it was at 78 μmol photons m⁻² S⁻¹ light intensity. In Cylindrospernum, total soluble proteins decreased with enhanced C0₂, and were highest at 18*C. In Anabaena, a light intensity of 65 μmol photons m⁻² S⁻¹ was best for maximum total soluble proteins. In Chlorella, CO₂ @ 850 ppm was most su...
Microalgae are reported as the efficient source of renewable biodiesel which should be able to me... more Microalgae are reported as the efficient source of renewable biodiesel which should be able to meet the global demand of transport fuels. Present study is focused on assessment of wastewater grown indigenous microalga Chlorella sp. for fuel quality parameters. This was successfully grown in secondary treated waste water diluted with tap water (25% dilution) in glass house. The microalga showed a dry weight of 0.849 g L−1 with lipid content of 27.1% on dry weight basis on 21st day of incubation. After transesterification, the yield of fatty acid methyl ester was 80.64% with major fatty acids as palmitic, linoleic, oleic and linolenic. The physical parameters predicted from empirical equations in the biodiesel showed cetane number as 56.5, iodine value of 75.5 g I2 100 g−1, high heating value 40.1 MJ kg−1, flash point 135 °C, kinematic viscosity 4.05 mm2 s−1 with density of 0.86 g cm3 and cold filter plugging point as 0.7 °C. Fourier transform infra-red (FTIR), 1H, 13C NMR spectrum co...
... 12, No. 2, (NS) pp. 181-185 (April-June, 2007) SHORT COMMUNICATION PHYSIOLOGICAL CHARACTERIZA... more ... 12, No. 2, (NS) pp. 181-185 (April-June, 2007) SHORT COMMUNICATION PHYSIOLOGICAL CHARACTERIZATION OF CYANOBACTERIAL ISOLATES FROM ORISSA AND WEST BENGAL SUDHIR SAXENA, BV SINGH, SAURABH TIWARI AND DOLLY WATTAL DHAR* ...
ABSTRACT Cost-efficient harvesting of microalgae is a major challenge due to their small size and... more ABSTRACT Cost-efficient harvesting of microalgae is a major challenge due to their small size and often low concentration in the culture medium. The flocculation efficacy of different inorganic and organic amendments was evaluated on various microalgae genera—one strain each belonging to Chlamydomonas, Chlorococcum, two of Botryococcus, and of Chlorella. An improvised medium comprising of commercial grade urea, single super phosphate, and muriate of potash was used to grow the microalgae for flocculation experiments. High pH induced increased flocculation efficiency (72–76 %) in selected microalgal strains. Ferric chloride was found to be the most efficient for most of the microalgal strains, while maize starch and rice starch proved superior for Chlorella sp. MCC6 and Botryococcus sp. MCC32. Although the highest flocculation efficiency was obtained with inorganic flocculant, i.e., ferric chloride (87.3 %) with Botryococcus MCC31, this was comparable with rice starch (86.8 %) for Botryococcus MCC32. This study showed that widely available cheaper biopolymers such as rice starch, maize, and potato starch can be promising flocculants due to their better harvesting efficiency (>80 %) and low price, thereby contributing to economical production of biodiesel from algae.
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