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CULTURE OF ALGAE FOR FOOD AND OTHER ORGANIC COMPOUNDS
Mass culture of algae for food and other organic compounds
TIME COURSE OF PHOTOSYNTHESIS IN BICARBONATE BUFFER IN SYNCHRONIZED CULTURES OF ALGAE
Time course of photosynthesis in bicarbonate buffer in synchronized cultures of algae
EFFECTS OF ILLUMINANCE NEAR AND BELOW LIGHT SATURATION ON THE TIME COURSE OF PHOTOSYNTHESIS IN SNYCHRONIZED CULTURES OF ALGAE
Effects of illuminance near and below light saturation on the time course of photosynthesis in synchronized cultures of algae
Algae as Food for Space Travel: A Review
Algae, other plants, and animals as food for space travel
Desert algae - Soil crusts and diaphanous substrata as algal habitats
Desert algae development in soil crusts and diaphanous substrata as algal habitats
Biosynthesis of extracellular polysaccharides by the blue-green alga Anabaena flos-aquae.
Extracellular polysaccharides biosynthesis by blue-green alga Anabaena flos-aquae
Soil Studies - Desert Microflora. XIII - Identification of Some Algae from Antarctica
Microscopic identification of Antarctic algae
Fasciculochloris, a new Chlorosphaeracean alga from a Connecticut soil
Chlorosphaeracean algae from Connecticut soil
Ecologic Relationships Between Bacteria and Algae in Mass Culture
Ecological relationships between bacteria and algae in mass culture
Survival of desert soil algae at extremely low temperatures.
Survival of desert algae at extremely low temperatures and diurnal freeze thaw cycles
Preliminary development and evaluation of an algae-based air regeneration system
The potential of air regeneration system based on the growth of microalgae on the surface of porous ceramic tubes is evaluated. The algae have been maintained in the system for extended periods, up to 360 days. Preliminary measurements of the photosynthetic capacity have been made for Chlorella vulgaris (UTEX 259), Neospongiococcum punctatum (UTEX 786), Stichococcus sp., and Gloeocapsa sp. Under standard test conditions (photosynthetic photon flux approximately 66 micromoles m-2 s-1, initial CO2 concentration approximately 450 micromoles mol-1), mature tubes remove up to 0.2 micromoles of CO2 per tube per minute. The rate of removal increases with photon flux up to at least 225 micromoles m-2 s-1 (PPF); peak rates of 0.35 micromoles of CO2 per tube per minute have been achieved with Chlorella vulgaris. These rates correspond to between 120 and 210 micromoles of CO2 removed per square meter of projected area per minute.
Lipid content and fatty acid composition of green algae Scenedesmus obliquus grown in a constant cell density apparatus
The lipids of alga Scenedesmus obliquus grown under controlled conditions were separated and fractionated by column and thin-layer chromatography, and fatty acid composition of each lipid component was studied by gas-liquid chromatography (GLC). Total lipids were 11.17%, and neutral lipid, glycolipid and phospholipid fractions were 7.24%, 2.45% and 1.48% on a dry weight basis, respectively. The major neutral lipids were diglycerides, triglycerides, free sterols, hydrocarbons and sterol esters. The glycolipids were: monogalactosyl diglyceride, digalactosyl diglyceride, esterified sterol glycoside, and sterol glycoside. The phospholipids included: phosphatidyl choline, phosphatidyl glycerol and phosphatidyl ethanolamine. Fourteen fatty acids were identified in the four lipid fractions by GLC. The main fatty acids were C18:2, C16:0, C18:3(alpha), C18:1, C16:3, C16:1, and C16:4. Total unsaturated fatty acid and essential fatty acid compositions of the total algal lipids were 80% and 38%, respectively.
The effect of low temperature on Antarctic endolithic green algae
Laboratory experiments show that undercooling to about -5 degrees C occurs in colonized Beacon sandstones of the Ross Desert, Antarctica. High-frequency temperature oscillations between 5 degrees C and -5 degrees C or -10 degrees C (which occur in nature on the rock surface) did not damage Hemichloris antarctica. In a cryomicroscope, H. antarctica appeared to be undamaged after slow or rapid cooling to -50 degrees C. 14CO2 incorporation after freezing to -20 degrees C was unaffected in H. antarctica or in Trebouxia sp. but slightly depressed in Stichococcus sp. (isolated from a less extreme Antarctic habitat). These results suggest that the freezing regime in the Antarctic desert is not injurious to endolithic algae. It is likely that the freezing-point depression inside the rock makes available liquid water for metabolic activity at subzero temperatures. Freezing may occur more frequently on the rock surface and contribute to the abiotic nature of the surface.
Partial purification and characterization of a Ca(2+)-dependent protein kinase from the green alga, Dunaliella salina
A calcium-dependent protein kinase was partially purified and characterized from the green alga Dunaliella salina. The enzyme was activated at free Ca2+ concentrations above 10(-7) molar. and half-maximal activation was at about 3 x 10(-7) molar. The optimum pH for its Ca(2+)-dependent activity was 7.5. The addition of various phospholipids and diolein had no effects on enzyme activity and did not alter the sensitivity of the enzyme toward Ca2+. The enzyme was inhibited by calmodulin antagonists, N-(6-aminohexyl)-1-naphthalene sulfonamide and N-(6-aminohexyl)-5-chloro-1-naphthalene sulfonamide in a dose-dependent manner while the protein kinase C inhibitor, sphingosine, had little effect on enzyme activity up to 800 micromolar. Immunoassay showed some calmodulin was present in the kinase preparations. However, it is unlikely the kinase was calmodulin regulated, since it still showed stimulation by Ca2+ in gel assays after being electrophoretically separated from calmodulin by two different methods. This gel method of detection of the enzyme indicated that a protein band with an apparent molecular weight of 40,000 showed protein kinase activity at each one of the several steps in the purification procedure. Gel assay analysis also showed that after native gel isoelectric focusing the partially purified kinase preparations had two bands with calcium-dependent activity, at isoelectric points 6.7 and 7.1. By molecular weight, by isoelectric point, and by a comparative immunoassay, the Dunaliella kinase appears to differ from at least some of the calcium-dependent, but calmodulin and phospholipid independent kinases described from higher plants.
Algae to Enhance Water Recovery for Future Space Habitats
Bioregenerative technologies have been suggested for human life support in space for decades. Such technologies have not yet been incorporated due to 1) assumed unreliability and 2) bioregeneration rates for given processes are slower when compared to equivalent physical/chemical treatment technologies. Slower treatment capacity for biological system result in larger technology infrastructure (i.e., higher mass, power, and volume requirements), and thus less attractive. Current ISS (International Space Station) life support systems are strictly physical/chemical. However, bioregenerative systems are being suggested for future surface systems (on the Moon or Mars) due to the limited access to resupplied materials and continued need for resiliency and sustainability. In the realm of water reclamation, the ISS system processes only urine, metabolic condensates, and hygiene (i.e., handwash and oral, no shower or laundry) waters with 75 percent closure. For future surface habitats with 4 crew members, approximately 30 liters per day of wastewater will be generated, containing estimated 850 milligrams per liter NH4-N. Conventional algae PBRs (photobioreactors) require dilution to accommodate such high concentrations of ammonium. If dilution is required, resulting technology hardware will increase dramatically in mass. A new approach was explored, whereby high carbon dioxide (1200-2000 parts per million) and light (400-600 micromoles per square meter per second) conditions were provided to treat the undiluted wastewater stream. Daily treatment capacity for Chlorella sorokiniana and Chlorella vulgaris was observed to be 85 and 107 milligrams NH4-N per gram of biomass, respectively. This preliminary study shows that there is capacity to increase ammonium removal rates by algal species, and thus reactor size (mass and volume) for future surface systems. Smaller reactor volumes will help bioregenerative treatment technologies compete with the presently accepted physical/chemical treatment technologies.