Green Alga Selenastrum Capricornutum Research Articles

Phosphorus removal from swine manure supernatant: Precipitant efficiency

In the absence of long term solutions for the management of swine manure, the present study proposes an emergency remedial measure aimed at reducing the eutrophic load of the supernatant of swine manure when discharge in the aquatic environment is unavoidable. Phosphate removal appears to be a temporary solution to the reduction of manure fertility for the aquatic environment. The efficiency of three phosphate precipitants, namely, alum (Al2(SO4)3), lime (Ca(OH)2), and zirconium tetrachloride (ZrCl4) was evaluated in 60 L experimental tanks. Alum yielded the best efficiency, both for the chemical precipitation of P and for algal growth potential reduction determined with the green alga Selenastrum capricornutum. Zirconium tetrachloride was also very active, but for a shorter period of time. Finally, lime was relatively less efficient.

Metabolism of benzo(A)pyrene by a dioxygenase enzyme system of the freshwater green alga selenastrumcapricornutum

The green alga Selenastrum capricornutum was incubated with benzo(a)-pyrene under an atmosphere of 20% (18)O2: 80% N2. The cis-11,12-dihydro-11,12-dihydroxybenzo(a)pyrene, cis-7,8-dihydro-7,8-dihydroxybenzo(a)pyrene and cis-4,5-dihydro-4,5-dihydroxybenzo(a)pyrene, were isolated by HPLC and analyzed by mass spectrometry. The metabolites produced molecular ions at m/z 290 and 286. Elemental analysis of the ion at m/z 290 gave an elemental composition of C20H14(18)O2 with 13% (18)O2 incorporation. The results indicate that S. capricornutum produces cis vicinal dihydrodiols from molecular oxygen via a dioxygenase enzyme pathway. The dioxygenase enzymes are characteristic of the bacterial metabolic pathway and unlike those of eukaryotic organisms which involve monooxygenase enzymes.

Growth of selenastrum capricornutum in the presence of synthetic surfactants

The green alga Selenastrum capricornutum Printz was cultured in a synthetic liquid medium and its yield was studied in the presence of 28 different synthetic surfactants. The surfactants were used in different concentrations depending on their inhibitory effects. It seemed that the tested compounds could be grouped into three types according to their effect on growth: “mild”, “hard” and “very hard” surfactants. The concentrations used were 0–500 ppm for “mild”, 0–50 (−100) ppm for “hard” and 0–10 ppm for “very hard” surfactants. Chemically, the surfactants belonged to several common types. Electrically, they were nonionic (13 compounds), anionic (9), cationic (3) and amphoteric (3). The cationics and amphoterics were very growth-inhibiting, as were some anionics and nonionics. Most of the tested surfactants were somewhat inhibitory, but some nonionics increased the growth of S. capricornutum at the concentrations tested. The relationships between the effects on growth and the chemical structure and behaviour of the surfactants are discussed.

Method for determining the temporal response of microbial phosphate transport affinity.

Nutrient transport affinities of nutrient-starved microbial populations were measured as initial slopes of plots of limiting-nutrient transport rates versus extracellular limiting-nutrient concentrations. A method was devised for the determination of soluble reactive phosphate (Pi) affinity in Pi-limited continuous culture (aT), which was then used as an indicator of the effects of light/dark cycle (LD) perturbations on the temporal Pi transport abilities of three species of freshwater algae. Cell division was asynchronous for the green alga Selenastrum capricornutum grown in continuous cultures exposed to LD cycles. An apparent rhythm in aT for Pi was greatly affected by the population size parameter. Cell division was phased for the green alga Scenedesmus quadricauda grown in LD continuous culture. A rhythm in aT for Pi was not greatly affected by the biomass parameter. Cell division was also phased in LD continuous culture for the blue-green alga (cyanobacterium) Synechococcus Nägeli, but rhythms in other parameters could not be detected. Synechococcus Nägeli was an extremely efficient Pi transporter at low Pi concentrations in LD continuous culture, and so aT could not be calculated. The results demonstrate that aT is well suited to describing the temporal response of Pi transport in LD-perturbed, Pi-limited continuous culture.

Determination of biologically available phosphorus using a radiobioassay technique

SUMMARY. A kinetic approach in which the uptake rate of simultaneous additions of orthophosphate and carrier‐free phosphorus‐ 32 by a standard culture of the green alga Selenastrum capricornutum under near neutral conditions was used to obtain an estimate of the readily available components of the total phosphorus pool in natural freshwater samples. A comparison was made between the values of the biologically available phosphorus obtained using this radiobioassay technique and those obtained by the soluble reactive phosphorus procedure for thirty‐one freshwater samples. Only about three‐quarters of the phosphorus measured as soluble reactive phosphorus was readily available to algae. The results agreed with those obtained in an earlier study in which an enzymatic procedure was used to determine orthophosphate. The results of tests carried out on the water samples used in this study were consistent with the conclusion that the presence of a hydrous ferric oxide‐orthophosphale complex in the samples caused the soluble reactive phosphorus value to be greater than the corresponding biologically available phosphorus value.

Stereospecificity in algal oxidation of the carcinogen benzo(a)pyrene

The green algaSelenastrum capricornutum Printz metabolizes benzo(a)pyrene to vicinal dihydrodiols. Two metabolites isolated from algal medium extracts have been identified ascis-4,5-dihydroxy-4,5-dihydrobenzo(a)pyrene andcis-7,8-dihydroxy-7,8-dihydro-benzo(a)pyrene. Notrans-dihydrodiols have been found. This stereospecificity is unlike that seen in fungal and mammalian systems, in which polycyclic aromatic compounds are metabolized totrans-dihydrodiols.

A rapid quantitative bioassay for the determination of biologically available bromacil in soils

AbstractA simple rapid bioassay is described for the determination of biologically available bromacil residues in soils. A clear aqueous extract was made from a soil fortified with a known amount of the herbicide, and similar extracts were made from samples of soil taken from plots that had been sprayed with a bromacil formulation at a rate of 4 kg ha−1. Samples of these extracts were added to a suspension of the unicellular green alga Selenastrum capricornutum. The net photosynthetic oxygen production by the alga was then measured using an oxygen electrode. The results were expressed as a percentage of the oxygen production by a control suspension. The concentration of biologically available bromacil was determined by reference to a previously established dose‐response curve of the percentage reduction in oxygen production against bromacil concentration. The accuracy of this bioassay was determined by comparing the results with those obtained using capillary gas‐liquid chromatography. The results obtained by the two different methods showed good agreement.

The phototoxicity of benzo[ a]pyrene in the green alga Selenastrum capricornutum

The effects of selected polycyclic aromatic hydrocarbons (PAHs) on the growth of the green alga Selenastrum capricornutum in three light regimens were examined. In gold fluorescent light, benzo[ a]pyrene (BaP) at 12 mg/liter (48 μmole/liter), benz[ a]anthracene (BaA) at 40 mg/liter (175 μmole/liter), anthracene (A) at 40 mg/liter (224 μmole/liter), and 13 metabolites of BaP each at 40 μg/liter had no effect on algal growth. In cool-white fluorescent light, 30% inhibition of algal growth occurred with 0.1 μmole/liter BaP, 8.0 μmole/liter BaA, and 40 μmole/liter A. BaP at 0.16 mg/liter (0.64 μmole/liter) totally inhibited growth. BaP concentrations an order of magnitude lower inhibited algal growth in fluorescent blacklight. In cool-white light, 5 of 13 metabolites of BaP (each 40 μg/liter) inhibited algal growth: 3,6-quinone; 6-hydroxy; 9-hydroxy; 3-hydroxy; and 1,6-quinone. Based on these results, PAHs and metabolites of BaP are selectively phototoxic to S. capricornutum due to the incident light intensity below 550 nm.

Comparative Acute Toxicity to Aquatic Organisms of Components of Coal-Derived Synthetic Fuels

Abstract In acute toxicity tests, green algae Selenastrum capricornutum, diatoms Nitzschia palea, adult snails Physa gyrina, juvenile cladocerans Daphnia magna, larval midges Chironomus tentans, adult amphipods Gammarus minus, juvenile fathead minnows Pimephales promelas, and embryo-larva stages of rainbow trout Salmo gairdneri and largemouth bass Micropterus salmoides were exposed for 4 hours (algae), 48 hours (arthropods and snails), 96 hours (fathead minnows), 7 days (largemouth bass), and 27 days (rainbow trout) to two phenols (phenol and β-naphthol), two azaarenes (quinoline and acridine), and two polycyclic aromatic hydrocarbons (naphthalene and phenanthrene) present in coal-derived oils. Median lethal or median effective concentrations (LC50s or EC50s) ranged from 0.03 mg/liter for phenanthrene and rainbow trout to 286.54 mg/liter for phenol and the green alga. The rainbow trout embryo-larva assay was the most sensitive of the test systems to all the chemicals except quinoline. For this last compou...

Evaluation de la bioaccumulation a l'aide d'un test biologique combine algue‐bacterie

Abstract This test attempts to demonstrate bioaccumulation by a simple, fast and standardized biological methodology. A culture of the green alga Selenastrum capricornutum is incubated in presence of mercury (HgCl2), PCB and/or industrial effluents. A culture lysate is prepared and analysed with a Microtox apparatus which uses the bioluminescent property of the bacteria Photobacterium phosphoreum. The biolumines‐cent reaction is affected proportionally to the toxicity of the lysate. A bioaccumulation potential index is then calculated by comparing the results of this test with those obtained with a lysate from a control culture. For each type of toxic substance tested, the bioaccumulation was also observed using analytical chemistry procedures. Certains masking problems were experimented with mercury. However with PCB and industrial effluents promising results were obtained.

The effect of bromacil of the net photosynthetic oxygen production of [formula omitted

The influence of bromacil on net photosynthetic oxygen production of a unicellular green alga Selenastrumcapricornutum was investigated with a view to developing a rapid quantitative bioassay to determine herbicide residues. Oxygen production was measured using a biological oxygen demand electrode and concentrations of bromacil as low as 10 μ1/1 were detected.

Toxicite des eaux de ruissellement de la fonte de neige en milieu urbain

There is a current paucity of information on the characteristics of water originating from melting snow in urbanized areas. In fact no data exist on the potential chronic toxicity of waters originating from melting snow combined with sewage waters of industrial and domestic activities. Bioassays were conducted on the green alga Selenastrum capricornutum to evaluate the composite effect of all pollutants occurring in waters originated from melting snow in urbanized areas and also to determine the long-term bioavailability of selected toxicants in these waters. The publication resumes a sampling study of two outfalls (Curotte-Papineau and Meilleur-Atlantique) from collector systems on the island of Montréal, Québec, Canada (see Fig. 1). Both sewer systems are of the combined surface runoff-wastewater type, are self contained and drain watersheds of 11.7 and 22.2 km 2 area respectively (see Table 1). The sampling program carried out in spring (March–May) 1978, was oriented towards the analysis of flow-quality relationships during two dry and three snowmelt periods. The flow from the intrusion of snowmelt into the sewage networks were due not only to high air temperature and solar radiation conditions but also to a heavy rainfall (9.67 mm; maximum intensity of 4.6 mm h −1. The principal water quality parameters studied were BOD 5, COD, Cl −, N in, P i, Pb, Cr, Zn, Cn − and SS (see Table 2). In addition a bioassay based on the fertility potential [the Selenastrum capricornutum Printz algal assay bottle test; U.S.E.P.A. (1978)] on filtered samples (1.2 μm GF/C) of waste water was used to detect any toxological qualities of the outfalls during both dry and snowmelt periods. An analysis of the relationship between chemical quality and the toxological properties of the samples from both sewage networks showed that water collected during a period of snowmelt without rain had a greater potential chronic toxicity and greater mean ratios of B EDTA/B than combined water collected during a dry climatic period (see Table 3). This toxicity is due mainly to inorganic compounds. However, the increase in water discharge rate during periods of snowmelt accompanied by rain results in an apparent dilution of the aquatic toxicants. The potential chronic toxicity of water during the latter periods is consequently reduced compared with combined waters during dry periods. Knowledge of relationships between water flow and the chronic toxicity characteristics of waste water from urban snowmelt is necessary in the planning of any future combined water treatment system.

Un test biologique pour caracteriser la toxicite des eaux usees

Bioassays using the green algae Selenastrum capricornutum Printz were conducted on wastewaters from two drainage basins on the Island of Montréal, Québec, Canada. Metal concentrations present in the wastewaters produced toxicity to the algal cultures, demonstrating that such a procedure is useful in determining the toxic activity of wastewaters.

Variation in cell composition and utilization of N and P for growth of Selenastrum capricornutum

AbstractCell material from different phases of growth for the green alga Selenastrum capricornutum Printz was analysed for major elements and chlorophyll a content. The ranges in percentage of the dry weight were 50–80%, 4.4–8.8%, 0.24–3.0%, and 0.20–3.23% for C, N, P and chlorophyll a, respectively. The dry weight per cell varied 2.3 times between different growth phases. A N/P‐quotient of about 10 (by weight) was found to be a critical level for Selenastrum when these elements were the most limiting nutrients for growth. 31 different organic N‐compounds were tested as single N sources in growth experiments with Selenastrum. At least 19 of them could be utilized to varying extent for algal growth. Three organic P‐compounds of six tested, were utilized for algal growth.Yield coefficients (mm3 cell volume/mg limiting nutrient element) for Selenastrum were determined with NO3, ‐N (yN= 134). NH4‐N (YN= 111) and PO4‐P (YP= 2580).

Mercury accumulation by the fresh water alga [formula omitted][formula omitted

The deposition of mercury in the environment continued unchecked until recently when accumulations of this toxicant were found to be potentially dangerous to man. Since outbreaks of mercury poisoning among people were first positively diagnosed in the early 1960s, Japan, Canada, Sweden and the US have actively engaged in research and established regulations to prevent further human poisoning. Much research has been devoted to assessment of the accumulation of mercury in fish and aquatic birds which may be consumed directly by man. Yet relatively little work has been directed at mercury uptake by lower aquatic organisms. At the base of the aquatic food web are the algae from which the majority of non-photosynthetic aquatic organisms derive most of their energy. It is therefore important to explore the pathways by which mercury may enter the food web at this lower trophic level. In the present study, laboratory cultures of the unicellular, fresh-water, green alga Selenastrum capricornutum were utilized to examine uptake of inorganic mercury. Selenastrum was chosen as the test organism due to its wide natural distribution and because it has previously received intensive use as a bioassay organism in limnological and ecological studies. 3 references, 2 figures.