Iracema Andrade Nascimento

Comparing the use of different domestic wastewaters for coupling microalgal production and nutrient removal.

The streams from municipal wastewater treatment plants (WWTP) have been considered a valuable medium for mass cultivation of algal biomass. The aim of this work is to test and compare the performance of Chlorella vulgaris on several streams from five stages, from two different WWTP. The results showed biomass yields ranging from 39 to 195mg dry-weightl(-1)days(-1). The best performance as biomass production was obtained with the centrate (effluent from drying the anaerobic sludge). After testing a wide range of N/P ratios with centrate, the highest productivity and growth rates were obtained with the original N/P ratio (2.0) of this stream. The highest removal rates were of 9.8 (N) and 3.0 (P) mgl(-1)days(-1), in the centrate. Finally, this research also suggests that microalgal production seems to be a promising process when coupled to wastewater treatment.

Influence of gamete density, salinity and temperature on the normal embryonic development of the mangrove oyster Crassostrea rhizophorae Guilding, 1828

Abstract Laboratory experiments were undertaken to determine the optimal environmental conditions and some of the other factors concerned in the development of Crassostrea rhizophorae embryos. Critical variables such as the number of spermatozoa per ovocyte during fertilization, the time of fertilization after gamete liberation, egg density, temperature and salinity were related to the proportion of normal D-larvae of C. rhizophorae in the resulting broods. The highest proportion of normal D-larvae was obtained at concentrations of 500–5000 spermatozoa/ovocyte, under conditions of 25‰ salinity at 25 ± 1°C. The optimal density of eggs, for the production of normal D-larvae, was 10 4 −4 × 10 4 ovocytes/l. If fertilization was delayed for more than 45 min after liberation of spermatozoa the proportion of normal D-larvae was greatly reduced. The experiments demonstrated that the temperature for developing embryos should be below 30°C. At 20 and 25°C there was a high proportion of normal D-larvae 24 h after fertilization. The ideal salinity for embryonic development in C. rhizophorae was 25–37‰. Below a salinity of 16‰, less than 2.5% of the D-larvae were normal.

Reproduction of ablated and unablated Penaeus schmitti in captivity using diets consisting of fresh-frozen natural and dried formulated feeds

Abstract Reproduction of Penaeus schmitti was achieved in a recirculating seawater system using three different diets: 100% fresh-frozen,50/50% fresh-frozen/dried and 100% dried formulated feeds. Shrimp fed the50/50% fresh-frozen/dried and 100% dried diets had significantly higher ( P P. schmitti reproductive processes which were monitored during the study. One hundred percent dried formulated feed induced the best maturation, spawning and fecundity. Results using the mixed diet were slightly lower, but did not differ significantly ( P > 0.05). The mixed and 100% fresh-frozen diets induced significantly higher ( P

Pathological findings in Crassostrea rhizophorae from Todos os Santos Bay, Bahia, Brazil

Abstract Types and frequencies of pathologies were investigated in Crassostrea rhizophorae before and following heavy oyster mortality in Todos os Santos Bay, Bahia, Brazil. The sporozoan Nematopsis sp. was the only parasite present in sufficient numbers to be an important mortality factor, but the intensity of Nematopsis infections remained low until after the major die-off. Pathologies such as ceroidosis, reduction or loss of stored glycogen, decreased gametogenesis, edema, and metaplasia of the digestive diverticula were consistent with the hypothesis of an external environmental stress factor that may have caused feeding to cease, the resultant weakness contributing to high mortalities.

Toxicity of water‐soluble fractions of biodiesel fuels derived from castor oil, palm oil, and waste cooking oil

Concerns over the sustained availability of fossil fuels and their impact on global warming and pollution have led to the search for fuels from renewable sources to address worldwide rising energy demands. Biodiesel is emerging as one of the possible solutions for the transport sector. It shows comparable engine performance to that of conventional diesel fuel, while reducing greenhouse gas emissions. However, the toxicity of products and effluents from the biodiesel industry has not yet been sufficiently investigated. Brazil has a very high potential as a biodiesel producer, in view of its climatic conditions and vast areas for cropland, with consequent environmental risks because of possible accidental biodiesel spillages into water bodies and runoff to coastal areas. This research determined the toxicity to two marine organisms of the water-soluble fractions (WSF) of three different biodiesel fuels obtained by methanol transesterification of castor oil (CO), palm oil (PO), and waste cooking oil (WCO). Microalgae and sea urchins were used as the test organisms, respectively, for culture-growth-inhibition and early-life-stage-toxicity tests. The toxicity levels of the analyzed biodiesel WSF showed the highest toxicity for the CO, followed by WCO and the PO. Methanol was the most prominent contaminant; concentrations increased over time in WSF samples stored up to 120 d.

Lipid profiling and corresponding biodiesel quality of Mortierella isabellina using different drying and extraction methods

Four lipid extraction methods (Bligh & Dyer, hexane & isopropanol, dichloromethane & methanol, and hexane) were evaluated to extract lipid from freeze- and oven-dried fungus Mortierella isabellina ATCC42613. The highest lipid yield (41.8%) was obtained from Bligh & Dyer extraction on the oven-dried fungal biomass with a methanol:chloroform:water ratio of 2:1:0.8. Other lipid extraction methods on both freeze- and oven-dried samples had lipid yields ranging from 20.7% to 35.9%. Non-polar lipid was the main lipid class (more than 90% of total lipid) in M. isabellina. Regarding fatty acid profile, there was no significant difference on fatty acid concentration between different drying and extraction methods. Estimation of biodiesel fuel properties using correlative models further demonstrated that the fungal biodiesel is a good alternative to fossil diesel.

Stress protein accumulation as an indicator of impact by the petroleum industry in Todos os Santos Bay, Brazil

The relative concentrations of stress proteins in juvenile mangrove oysters (Crassostrea rhizophorae), from six study sites in Todos os Santos Bay, Bahia, Brazil, were used to evaluate the possibility of chronic environmental impact induced by 40 years of exposure to the local petroleum industry. Replicated tissue samples from oysters at four sites associated with the extraction, transport and refinement of petroleum, and from two control sites, were used for stress protein (60 kDa) determination. The relative levels of stress proteins were statistically compared by standard methods. Friedman nonparametric analysis of variance, followed by multiple comparisons among samples, revealed significant differences in stress protein levels. Oysters from sites associated with the extraction and transport of petroleum had the highest relative concentrations of stress proteins, while the control areas revealed minimum concentrations. Samples from the refinery site, where oyster populations were severely reduced, did not differ from the control sites. Comparisons with parallel studies on the toxicity of aquatic substrates at the same sites revealed that stress protein analyses were useful in evaluating chronic environmental impact, within the tolerance limits of C. rhizophorae, but that the stress response diminished significantly when conditions approached the lethal limits for this species. The stress protein response appears to serve as a valid biomonitoring method under chronic, sublethal exposures, before biological responses become evident at the organismic or population levels, but may not serve well when the stressor intensity is at or near the lethal tolerance level.

Reducing the life cycle GHG emissions of microalgal biodiesel through integration with ethanol production system.

Despite environmental benefits of algal-biofuels, the energy-intensive systems for producing microalgae-feedstock may result in high GHG emissions. Trying to overcome energy-costs, this research analyzed the biodiesel production system via dry-route, based on Chlorella vulgaris cultivated in raceways, by comparing the GHG-footprints of diverse microalgae-biodiesel scenarios. These involved: the single system of biomass production (C0); the application of pyrolysis on the residual microalgal biomass (cake) from the oil extraction process (C1); the same as C0, with anaerobic cake co-digested with cattle manure (C2); the same conditions as in C1 and C2, by integrating in both cases (respectively C3 and C4), the microalgae cultivation with an autonomous ethanol distillery. The reduction of GHG emissions in scenarios with no such integration (C1 and C2), compared to CO, was insignificant (0.53% and 4.67%, respectively), whereas in the scenarios with integration with ethanol production system, the improvements were 53.57% for C3 and 63.84% for C4.

Changes in the condition index for mangrove oysters (Crassostrea rhizophorae) from Todos os Santos Bay, Salvador, Brazil

Abstract The condition index was calculated for two samples of 600 C. rhizophorae taken from Jacuruna farm in September–October 1977 (spawning period) and December 1977–January 1978 (post-spawning period). There was a significant difference ( P ≤ 0.05). Over the size range 2.1 to 10.0 cm (height) the condition index ranged from 59.0 ± 16.2 to 71.8 ± 30.5 for the spawning period, but was only 27.1 ± 10.2 to 43.9 ± 33.0 for the post-spawning period. The size class 4.1 to 6.0 cm gave the best commercial yields and was considered more suitable for the shucked oyster than the fresh oyster market.

Determination of the optimum commercial size for the mangrove oyster (Crassostrea rhizophorae) in Todos os Santos Bay, Brazil

Abstract Pilot studies were conducted in 1977–1978 on the cultivation of mangrove oysters in the Jacuruna River estuary at Todos os Santos Bay, Salvador, Brazil. Growth characteristics were studied by comparing the relationships between total live weight, volume of the shell cavity fluid and yield of meat, and dry body weight to size (height). The most economically feasible proposition was production of approximately 7 cm high oysters for the shucked oyster market rather than for the fresh oyster market. The harvesting of oysters less than 4 cm high was not considered desirable because it might reduce reproductive capacity. In oysters higher than 7 cm, growth rate and meat production decreased and did not warrant further cultivation.